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Yoonki’s Ultimate Guide to Biohackers     

Art credits go to: Paizo Inc, Rosko 3Dart, Johan Wahlback, Alexey Gogin, Artyom Kim, 
Guide Information
This guide is made by Yoonki (/u/Craios125, Yoonki#7514 on Discord).


If you enjoy this guide, hey, maybe consider buying me a beer. 
Your support helps motivate me to update this guide and write new ones! Thank you very much for your patronage. The link to my PayPal is http://paypal.me/craios125. Won’t take more than a few clicks. 😋

Starfinder is a very big game, and I want this guide to focus specifically on the Biohacker chassis. I’ll highlight some pieces of gear and race options, but I’ll let you round out the specific details of your individual character. 


I shall be using and analyzing the features and options showcased in the Core Rulebook, Armory, Pact Worlds, Starship Operations Manual, Alien Archives, most Adventure Paths and Character Operations Manual books in this guide.

For readability, paying respect to online guide traditions, and because I want to be part of the cool kids club, I’ll be using color-coding for options in the guide:

Blue - awesome, strong options for the majority of scenarios that might come up in the game
Green - solid options that are definitely playable and usable, but perhaps not as powerful or versatile as the blue ones.
Orange - decent options for specific builds and/or specific types of campaigns, but might be kind of niche.
Red - options that are either so niche that they might never come up, or are just straight up underpowered. Keep in mind that Starfinder is a game you and your friends play for fun, so feel free to talk to your GM about changing some of them, or making sure there will be opportunities to use them.
Varied Colors - mean features that are better/worse at different periods of the game, different types of campaigns, or with different party compositions.











Guide History

Version
Date
Changes
1.0
2020-12-14
Initial version
1.1
2020-12-15
Improved wordings on some ratings, updated the microlab’s scan feature description. Clarified that you can’t use the microlab to craft serums, rules as written. Clarified the description of powerful biohacks.
1.2
2020-12-17
Updated the rating on double tap, versatile specialization, improved demoralize and Powered Armor Jockey.
2.0
2022-06-23
Added all of multiclass options with Precog & Nanocyte, archetypes, some feats and a bunch of class options published in Tech Revolution, Galaxy Exploration Manual, Galactic Magic and every adventure. Changed ratings & descriptions on older content to reflect new changes. Improved the sample builds to reflect new options. Improved the descriptions on weapon focus, advanced melee/longarm proficiency, versatile specialization and weapon focus to reflect a possible way to save a theorem.
2.1
2022-06727
Updated Pharmacology, Laugh at Danger, Battleflower, Coagulant and Fleet.
2.2
2022-08-01
Added the halfling race & quick quip/goad/clever retort feats.



















Biohacker Overview
The biohacker is an Intelligence or Wisdom-based martial class, using powerful biohacks to grant useful buffs and crippling debuffs to control the battlefield. Their skillset acts as probably the single most powerful damage amplifier for the entire party, capable of making nearly any other character shine far more brightly. It is also pretty varied, thanks to their high Intelligence and versatile abilities. Additionally, thanks to some features, they can actually dish out fairly respectable damage that is more akin to a more dedicated damage build than a support build. Both in melee and at range, the biohacker can sometimes completely trivialize encounters with the right ability applied at the right time.
It is worth to point out that, despite having Intelligence as their key ability scores, Biohackers simply can not rely on Intelligence alone to be effective and will also have to specialize either in Strength or Dexterity to keep up in combat.
Their abilities are rather poorly edited and worded, which makes them seem very bulky and complex, but it really isn’t all that confusing when you read into them.

Party Roles
Keep in mind, you’re playing a roleplaying game. Every single class in the game can be built to fit most roles in the game. Every character will have a lot of roles to them. However, naturally, some classes shine more in certain roles:

Damage-dealer - Biohackers are decent damage dealers (as always, melee builds deal more damage than ranged ones). Injection Expert gives them proficiency in all the weapons they need, meaning that damage-dealing builds aren’t even particularly feat-intensive. It also gives us bonuses to attack that helps deal with our ¾ BAB progression. The fact that they’re so tied to injection weapons means it’ll be hard for them to scavenge high level boss weaponry. That being said, no abilities in their skillest (outside the lv20 superserum) allows them to really lay enemies to waste with massive damage. Good thing that injection weapons usually deal very respectable damage.
Tank - no heavy armor, no proficiency in shields, no defensive tactics or theorems. A couple of boosters do improve your survivability a bit, allowing for some gimmicky tank builds. The main way a “dedicated” tank build would be semi-viable is by applying biohacks that reduce enemy accuracy or require several feats.
Support - biohackers have some neat buffs that are easy and quick to apply and recharge on a short rest. However, the buffs usually aren’t as impressive as some other classes can apply. Studious biohackers, some Biohackers have ways of applying healing to the health pool (rather rare in Starfinder), while instinctive ones can (eventually) remove a lot of debuffs. Biohackers’ injection ranged weapons can be loaded up with a bunch of different chems (such as healing serums) to keep the party alive and in shape.
Debuffer - This is where the biohacker’s main power lies. Their debuffs can leave the enemies so vulnerable to attacks that you can easily deal even with significant opponents. Their debuffs act as an extremely powerful damage amplifier for the entire party. That being said, their debuffs usually aren’t necessarily debilitating, like the mage class’. Additionally, injection expert makes applying medicinals and poisons a breeze.
Socialite - personally, I never liked “party face” defined as a “role”, as it implies that only one specific character is supposed to be interacting with NPCs. Feel free (and encouraged) to do so even if your social scores aren’t the highest. Aiding is a thing in the game, too. However, if we do analyze the “social interaction” options, Biohackers really don’t have anything particularly unique to offer. They do gain Culture and Diplomacy as class skills, which is nice. And, thanks to either having Intelligence as their key ability score or having the instinctive bonus, they are likely to have enough skill ranks to put some into social skills.
Utility - Biohackers have a powerful way to apply enhancement bonus to any skill check by using a basic booster to anyone in their party. It’s nice. Biohackers also have a very wide array of class skills and a good amount of skill ranks to spread around, meaning they can act as decent skill monkeys. Finally, their microlab feature makes identifying enemies an absolute breeze, making it easy for your party to devise a great winning combat plan. 

Ability Scores
The value of different ability scores depends heavily on your build and playstyle.

Strength - biohackers work perfectly well in melee. If you’re a melee build you want  to start with 16 in this, but ranged characters can easily drop it to 8.
Dexterity - crucial for both melee and ranged Biohackers. Even builds that use heavy armors will eventually want a decent bonus here. Melee builds in heavy armor can leave this at 10 or 12 at chargen. Those in light armor want at least 14, while ranged builds want 16-18.
Constitution - Starfinder’s stamina system makes having very high Constitution not exactly necessary, but still kind of important. Ranged characters can get away with 10 or even 8 here, especially if they can stay in cover or behind a strong line of melee party members. Melee Biohackers will likely need at least 12-14 here to get some staying power.
Intelligence - studious Biohacker’s key ability score. Additionally, studious biohackers get to apply this bonus to both Perception and Sense motive, instead of Wisdom, which is awesome. Now, theoretically speaking, even studious biohackers could leave this score lower, as you can make do with just 3 biohacks per 10-minute rest and just never pick biohacks that require saving throws. In such case, leaving this at 14 at chargen is fine. Most studious biohackers will want to have this at 16, however. 18 is likely overkill. Instinctive biohackers can safely dump this to 8, if they have enough skill ranks.
Wisdom - instinctive Biohacker’s key ability score. They (similar to the studious ones with Intelligence) may leave this at just 14 at chargen, but likely want 16. 18 is, once again, probably overkill. However, even studious Biohackers likely do not want to dump this to 8, since Will isn’t our strong save and having it be extremely weak is very dangerous.
Charisma - it’s either completely useless for you, or can allow you to completely talk your way out of combat. There’s little in the Biohacker chassis that requires Charisma, so you can dump it to 8. But do you want to..? Note that you can try to shore up your Charisma with personal upgrades a bit. A build with improved demoralize or the feint feats as a move action can be very strong if you want to be the biggest thorn in the enemy’s side.

Starship Combat 
Starship combat is featured in most adventure paths, and it’s a staple of sci-fi adventuring. One extremely important thing to consider here are the TIMs added in the Starship Operations Manual. The ones applicable to you are the biohacks and injection expert. Roles-wise you have the skill ranks to be at least okay in any role.

Captain - you likely do not have the Charisma to handle this. The biohacks TIM lets us get some use out of the Captain actions in the Science Officer role.
Chief Mate - might be decent if you have the Dexterity and Acrobatics to handle it. 
Engineer - one of two natural positions for the studious biohacker. Engineering is our class skill, so this is bound to be good. Instinctive biohackers likely won’t have the Intelligence to carry this. The injection expert TIM is amazing when it does come up, but likely won’t come up all that often.
Gunner - piloting isn’t a class skill for the Biohacker and we’re a ¾ BAB class. There are probably better options. If you spec into Piloting and are a ranged build it could still be okay, though.
Magic Officer - the DCs on some of the Magic Officer abilities are pretty steep, but an instinctive biohacker who gets a high Wisdom score, somehow gets Mysticism as a class skill and selects it as one of their two chosen instinctive skills can actually do really well here.
Pilot - Piloting isn’t a class skill for us, but ranged builds can be built to be decent here.
Science Officer - studious Biohackers can do extremely well here. The biohacks TIM allows us to nab a good Captain action. This might be either completely unviable for an instinctive biohacker, or require some Intelligence investment.

Races
Starfinder has a very wide variety of races. A lot of them don’t change the way you play in a major way and simply provide a nice benefit or bonus. As such, there isn’t really a need to explore every single race. Instead, I’ll break down core races and highlight a few races that are especially nice or interesting.

Ranged Biohackers will want to pick races that provide a bonus to Intelligence/Wisdom and/or Dexterity. Any race that provides a bonus to both is great. Any race that provides a bonus to either is good. Those that provide a penalty to one of them is bad. The rest are decent.
Melee Biohackers will want to pick races that provide a bonus to Strength and either Constitution or Intelligence/Wisdom. Races that provide a bonus  to at two of those are great. Those with a bonus to either Strength or Intelligence/Wisdom are good. If a race has penalty to either Strength, Constitution or Intelligence/Wisdom it’s probably bad. The rest are decent.


Android (Companion, Laborer) - bonus to INT and DEX is excellent. Infosphere Integration makes for an easy way to get more skill specialization. The upgrade slot makes it easy to put some form of darkvision into them for cheap, in case you lose it through alternate features. Rather nice for light armor, too. Default ability distribution is flawless for ranged builds, while Laborers are flawless for melee builds. Very strong pick.
Kasatha (Akitonian Settler, Nomad or Kasath Native) - Kasathas make great instinctive Biohackers, with the default Kasatha having an excellent distribution for melee Biohackers, while the Settler is awesome for ranged builds. 4 arms makes it easier to fit in a shield for heavy armor builds. Personal Traditions allows you to shore up having a weak save, while Crew Member is an easy way to get really good at Piloting.
Human (Featherlight or Gravity Dweller) - as usual, they’re great as literally any class in the game and you can not go wrong with them. More feats are great. Biohackers can pick Dusk Sight to have an even better Perception bonus. 
Lashunta (Korasha, Damaya or Mind Forward) - pretty fun set of psychic abilities. The racial bonuses to skills are also pretty rare and nice, but nothing too special.
Shirren (Scout or Courtier) - default Shirren are great as instinctive melee Biohackers. Scouts make perfect studious ranged Biohackers. Aside from that, they have some nice teamwork bonuses once per day. Individual obsession is nice for Studious Biohackers that dumped Intelligence.
Vesk (Low Gravity, Venomthought, Cave, Warblood) - Vesk are amazing for melee builds and Biohackers no exception. Low Gravity and Cave adjustments are flawless for ranged characters, while Warblood are great for melee ones. Observant provides a huge bonus to an often used skill, while Armor Savant is excellent for protection. You really can’t go wrong with this.
Ysoki (Anthropomorphic, Nograv, Survivor) - flawless for ranged Biohackers. Also makes you stronger at doing tech stuff. Moxie together with their small size makes for insane cover bonuses. Scrappy is great for melee builds.
Gosclaw - excellent ability scores for a studious ranged biohacker. Having fire resistance is excellent, because that’s a common damage type. Getting a racial bonus to Physical science is excellent for our microlab, and a racial bonus to three skills is epic. Burrow speed makes hiding easy peasy.
Orc - one of the best melee races. Conditioned focus allows us to take Intimidation as a class skill (works even better if you have a theme that gives you Intimidation), which combos well with frightening injection. +4 STR helps us get precious ability scores, while Orc Ferocity allows us to stay in the fight longer. Same as all races with light sensitivity, don’t forget your fashionable lightvision shades.
Note: remember that the FAQ removed the “receives an adjustment of +1 to the ability score associated with the chosen skill” line from conditioned focus.
Bear, Uplifted - great ability score adjustment for melee Biohackers, improved charges are always great on melee characters, and the improved movement speed is welcome for any heavy armor-wearing character. Large size also technically makes you threaten more areas, even without reach.
Dwarf - great bit of adjustment for both studious and instinctive Biohackers. They are notable for melee builds, as weapon familiarity grants full specialization with advanced melee weapons, meaning you do not have to pick up arms expert at lv8. Slow but steady is convenient for heavy armor.
Halfling (Stout) - default ones are great for ranged builds, while Stout halflings make good melee Biohackers. Skittish is excellent for melee builds, while ranged biohackers will be very happy with the needler alt feature, giving a lot of flexibility with serums.
Izalguun - they get STR, INT, racial bonuses to two tech skill some Biohackers may be interested in and a 10-foot reach, but the rather small speed in bipedal form and penalty to DEX really hurt them.
Strix - excellent abilities for ranged characters. Great bonuses to skills and flying speed are huge benefits for ranged Biohackers.
Themes
Themes are a core part of your character’s customization. Most characters won’t suffer too much even if they don’t pick a theme that matches their most important ability score. Just remember that a +1 does make you eligible for different feats. For example, you may have 12 DEX, then take the Ace Pilot theme to get a total of 13 DEX, making you eligible for the Mobility feat.
As such, I won’t be making any ratings on the Themes, because they really should just be something you choose for the narrative bonus. However, for optimization purposes, it is best to pick themes that make you eligible to a feat that you really want, such as pushing your STR to 13 for Powered Armor Proficiency.
Skills
Skill options are very subjective and personal. Two very important skills to point out, however, are LIfe Science and Physical Science. Pretty much all Biohackers will want to have maximum ranks in both skills, due to the fact that custom microlab allows us to use those skills to identify any enemy. As for the other skills, you probably want to grab some ranks into Perception and then spend the rest of the skill ranks based on your party role and preferred Starship combat role. Simply pick the skills you have the highest ability scores in, or wish to be good in. 
Gear
There’s a giant plethora of items and gear options in Starfinder, to the point that they can easily be their own guide. For those who are new to Starfinder in general, allow me to write down the items that literally every Biohacker (and pretty much every other class) needs from lv1 onwards:

1) Armor. You want a set of armor that fits your ability scores and proficiencies. You want it to stay at worst around 2 levels below your current level, but you usually want to keep it up with your level or one less. If you have high Dexterity - you want to use light armor. If you have low Dexterity (and the proficiency for it) - you want Heavy armor. Powered armor is another option for high level characters.
2) Weapon. Always important, always necessary. Weapons scale extremely slowly in the beginning (to the point where lv5 weapons basically deal as much damage as lv1 weapons), so you can save some money on buying an “ol’ reliable”. However, as the levels progress, you might see a huge jump of damage the higher level you get to the point where using lv17 weapons at lv19 can be a significant disadvantage. 
For Biohackers - you’re looking for injection weapons. All weapon types have them, so you do have some options. Hop on TheHiddenTruth’s melee or ranged weapon list and just CTRL+F “injection”. The relevant options should pop up.
It is recommended to get the conserving fusion on your ranged weapons, so you don’t waste biohacks on a miss.
3) Basic adventuring gear. This really depends on the kind of games you play, but, in a nutshell: a backpack, some rations, and somewhere to sleep.

That’s it. Those are the only things that you REALLY want. Literally everything else you buy is entirely up to you and what sort of character you want to play. Even if you are only going to be buying weapons and armors - you’ll still be generally fine. Maybe grab a ring of resistance to shore up at least one of your saves.
Additionally, Biohackers can be really damn good at crafting serums. Or not. Thing is, microlab allows you to use your Physical or Life Science to craft serums, but doesn’t actually count as workshop and tools to create them in the field - as written. That being said, talk to your GM! It’s a very common homerule to allow microlabs to create serums. Serums are an iconic part of the class’ identity, after all. If you combine speedy serums with master crafter and a high skill rank - you can pop those babies out at an enviable speed, giving you an entire new level of versatility and flexibility (though it still uses up UPBs. Oh well).
Note that all serums that may have a yellow or even red rating may still be useful, since you can craft them fairly quickly and when they are directly needed.


List of all serums (in order of price): serum of appearance change; serum of healing mk 1-3; serum of hibernation (diluted and potent); serum, lingo; gravity serum; rad-out serum; serum of *** shift; polymorphic serum mk 1-6; serum, daywalker; adaptive serum mk 1-3; serum, shadowblend; serum, x-ray; bloodbrother serum; dawnflower melange; pact world serum (aballon spark, absalom affable, akiton rustrider, bretheda effervescent, castrovel effloresce, diaspora daredevil, eox deliquesce, idari gold, triaxus dragonsight, verces gleam); serum, veracity; serum of enhancement (commando, diplomat, scientist, sensate, sneak, warrior); starmetal serums (abysium philter, djezet draught, horacalcum mélange, inubrix brew, noqual elixir, siccatite tonic); regeneration serum; serum, close-quarters; sophic philter; haeshi-shaa serum.
Class Ability Overview
Class Features

6 Hit Points / Stamina Points per level - decent amount, though nothing terribly special. Basically standard.
Key Ability Score (Intelligence/Wisdom) - both options are great (Wisdom is applied to the Will saving throw, so it’ll be higher, but studious scientific method boosts Will saves, so picking Intelligence isn’t a big disadvantage). Intelligence grants more skill ranks and affects a wider variety of skills.
Class Skills - 4+ is not a lot (though the studious Biohacker’s high Intelligence will help deal with that), but the selection of skills is rather excellent: social, technological and exploration skills are all here. Shame that physical skills like Acrobatics and Athletics are missing. Don’t forget that instinctive scientific method gives free skill ranks!
Proficiencies - only light armor, basic melee, small arms and grenades. Pretty poor choice. Injection expert feature helps us deal with our weapon proficiency, granting us proficiency in all injection weapons. Some melee Biohackers may want to grab the heavy armor proficiency feat, however.
Custom Microlab - this is a very big and rather poorly-worded feature that gives you many abilities. For ease of understanding, I’ll break it down into specific bullet points. Try to think about how you flavor it! Bonus points for tying it to your scientific method. Is your microlab a wrist-mounted computer with a hyper AI that quickly synthesizes the needed chemical? Is it a lithe shoulder-mounted artificial robot that scans and feeds information to you? Is it an ancient arcane orb you’ve recovered from a tomb that slowly floats around you and divines diseases and produces temporary needles of force energy? Or perhaps your entire body’s nervous and hormonal system has been modified to turn you into an analytical machine, capable of scanning with your eyes and deliver biohacks with sharp enhanced claws?
The microlab acts as a basic medkit & chemalyzer. It’s a nice, flavorful bonus, but both of those items are already very cheap, so this is nothing special. At lv5 it acts as an advanced medkit and at lv9 - a medical lab. Both are nice upgrades that will save you money and will help you support the party more.
This feature allows you to craft serums using Physical Science or Life Science, and they do not count as magical. It’s a nice bonus, but not exactly a gamechanger. However, talk to your GM. It’s a common houserule to allow microlab to craft serums in the field, or just homebrew an item that’d allow one to craft in the field (there's good basis for that already). There’s a wide amount of serums in the game, and, if your GM facilitates crafting in the field, combined with master crafter feat and the crafting rules, you’ll basically be able to craft a needed serum even in the middle of a dungeon, far away from your ship or any other workshop.
Note: the breakdown of every available serum is in the Gear description!
As a move action you can identify any creature using either Physical Science or Life Science, taking an automatic 20 as the result of the dice roll. The range starts at 60 feet, but eventually increases to 120). This is by far the best feature of the custom microlab, allowing you to automatically learn any ability the creature may have. Some people really don’t like this feature, due to the fact that it gives you a near meta knowledge, knowing the name and being of any creature your party encounters, no matter how enigmatic. However, there’s an easy fix to that - just assume your microlab scans the creature and analyzes its potential abilities based on its anatomy or composition and skips the name.
This is an excellent feature and something you should definitely use nearly any time you’re fighting some kind of an alien to learn its weakest save (helps your party’s mage), its unique abilities, its resistances and weaknesses.
Scan your party to automatically hit them when trying to apply biohacks to them. Basically this facilitates you actually being able to use your abilities to support your party in combat. 
Note: this requires the scanned party member to be within the microlab’s range AND requires you to shoot/stab them as a standard action, meaning you can’t weave that into a full attack. 
Biohacks - another really powerful and really poorly worded feature that is the staple of the Biohacker class. To break it down:
You get 1 + your INT (if studious) or WIS (if instinctive) biohacks at a time. Minor biohacks do not spend your biohacks and are just minor effects you can apply as often as you’d like.
Your biohacks refresh both after you perform your daily preparations after an 8-hour rest and after a 10-minute rest to recover Stamina Points (meaning you have to spend 1 RP). This basically means your biohacks are very easy to recover so you should use them very often. 
Biohacks are either boosters (which buff your target with some beneficial ability) or inhibitors (which debuff your target with some hampering limitation).
Any time you make an attack, but before you roll an attack roll you may apply one biohack to the attack. If you miss with a ranged attack - that biohack is wasted and lost. If you miss that attack with a melee weapon - it’s not wasted.
If you have no weapon, you can also apply a biohack with a needle (that would also need to be drawn like any other weapon), which counts as a basic melee weapon. You can then attack a target within your melee reach with it. If the target doesn’t resist 1 piercing damage (the needle doesn’t actually deal any damage itself - it’s 0, not 1) - the target is affected with the biohack. Good to remember for boosters for your buddies within reach, since you don’t have to shoot them.
As a standard action you can attack yourself, a friendly or unconscious target you’ve attuned with your custom microlab to automatically succeed on the attack roll. Note that if you target a friendly target with a full attack - you still need to beat your buddy’s AC to apply the hack to them.
Note that you do not need to prep your biohacks in advance, so you can decide which biohack you make when you use it.
All Biohackers know the basic boosters, basic inhibitors and minor biohacks. However, fields of study add additional biohacks.
Basic Boosters - decent selection of buffs. Duration: number of rounds equal to your key ability score modifier (minimum 1 round).
+1 AC - decent buff, but only something you’ll be applying pre-combat or when you have no way to attack an enemy.
+2 to skill checks - excellent biohack that you should always keep in mind, even out of combat. The enhancement bonus stacks with any other non-enhancement bonus, and they’re fairly rare. Combined with an Aid Another action that’s a +4 to the check. Very nice!
+10 to one movement speed - the bonus is situationally nice to prep before combat, or when speed is an important factor, but enhancement bonus to speed is actually quite easy to get through augmentations, armor upgrades and some other ways.
Basic Inhibitor - some very useful debuffs to apply on the enemies. Duration: number of rounds equal to 3 + your key 	ability score modifier (minimum 1 round) OR until you apply a different basic inhibitor.
-2 AC - this is the money right here. A -2 AC that might stack with many other ways of reducing AC (the GM decides which penalties stack, according to the rules), like spells and circumstance.
Reduced DR - it’s either useless, or amazing. However, since you always have that -2 AC it’s always nice to have it around.
Reduced Resistance - same as reduced DR, but mostly only if the whole party has a weapon/attack of the same energy type.
Minor Biohacks - do not use up one of your biohacks and can be applied as often as you like.
Minor Booster - some minor stabilization and dealing with poisons. Pretty situational, but nice to have.
Minor Inhibitor - simple solid debuff.
Injection Expert - fantastic ability that makes the biohacker have significantly more bite than most other support classes. This gives you proficiency in all injection weapons and a solid +1/2/3 bonus to your attack rolls (which helps offset your ¾ BAB. Additionally, you can choose not to deal damage to your buddy when you hit them with an injection weapon, but still apply any drug, biohack or medicinal. Finally, this allows you to be far more flexible with your medicinals and serums by loading them into your magazine. For example, your needler rifle can have 9 normal darts, 2 darts with a healing serum and 1 dart with a poison - and then you can make a full attack, applying 1 dart with a healing serum to a dying party member and 1 dart with a poison at an enemy. Excellent and flexible ability.
Pro tip: adding only half your level to damage of longarms and advanced melee injection weapons can definitely hurt a lot, so it is recommended to either use a lv8 arms expert theorem or spend 2 feats to gain weapon proficiency in either advanced melee or longarms (depending on your build). The latter option would also make you eligible for weapon focus.
Primary Field of Study - grants you one of several fields of study, which let you use their breakthroughs and biohacks. They will be broken down after class features. 
Scientific Method - a personality-defining Biohacker feature that decides on how you approach your craft. Both methods are excellent for different things. Your choice here changes the spark of ingenuity feature as well as the field dressing and medication mastery theorems.
Studious - allows you to use Intelligence as your key ability score, shores up your weak Will saving throw, provides a nice bonus to skills you’ll be using very often and allows you to use Intelligence for Perception and Sense Motive checks.
This option is stronger as a support due to the fact that restoring health with field dressing theorem is much more preferable to Stamina, as healing HP is tricky in Starfinder.
Try to think about what made or defines your Biohacker as studious. Did you finish a prestigious university (if so - try writing a thesis to fit your primary field of study, like “Practical Applications of Short-Lived Hyper-Agitated Neurotransmitter-Affecting Nanites in Field Scenarios")? Did you train under a great master of the medical arts? Were you a specialized biological warfare commando trained by an elite secret organization?
Instinctive - allows you to use Wisdom as your key ability score (yay, decent Will saves), grants you a free skill rank to two skills (and an insight bonus to them) and allows you to use Wisdom for Life Science, Physical Science and Medicine. 
Try to think about what made or defines your Biohacker as instinctive. Are you a failed university student who watched quack doctor shows on the infonet and ran his own dubious sawbones clinic in the really bad side of town? Are you a mystical shaman from an alien planet who uses borderline arcane traditions of your forefathers?
Theorem - here are your class feats. Solid set of varied options to expand your character’s abilities.
Spark of Ingenuity - up to three times per day allows you to combo biohacks in special ways.
Studious spark allows you to spend 2 uses of the biohacks feature to combine two basic or minor biohacks with a single shot. Note that you can not combine it with your field of study biohacks (nor superserum), and if you miss with a ranged attack, that means you just wasted two biohacks, so be wary.
Instinctive spark allows you to remove progressively more grave conditions when applying boosters, which is nice, but quite situational. Starting from lv9 you can apply off-target or dazzled with any of your inhibitors (which includes minor biohacks!), turning this feature significantly more attractive and universally useful.
Weapon Specialization - better than nothing, but adding half your level to longarm or advanced melee attacks sucks. You almost definitely want to end up getting full level to damage and you have two major ways of achieving that goal:
You can persevere dealing lower damage until level 8, at which point you learn the arms expert theorem, which’d allow you to add your full level to damage with injection weapons. This uses up a precious theorem, which are always in high demand.
Alternatively, you can take two feats: weapon proficiency (advanced melee for melee builds, longarms for ranged builds) + the versatile specialization, thus giving you “conventional” access to those advanced injection weapons. This has three benefits: it saves you a theorem at level 8, lets you deal your full damage as early as level 3 and makes you eligible for weapon focus (which gives up to +2 to your attack rolls, which is huge). But it does use up two whole feats. 
Second Field of Study - we get a second one? Excellent.
Tertiary Field of Study - AND a third one? Now you’re just spoiling us.
Resolve Analysis - neat. Except most Biohackers don’t have that many uses for RP.
Superserum - this is awesome. Sad that it comes so late. Note that they’re still biohacks, so have the same limitations on use as they do, except you also only get 2 per day and don’t recover them after a 10-minute rest. Missing with this one will really suck.
The first option is to use it as a raise dead or regenerate spell. The latter is pretty obvious, but the former is a bit confusing. I assume you shouldn’t need the 5000+ credit spirit beacon..? 
The second one is to cause massive internal damage. 17d10 is nothing to scoff at and the debuffs on a failed save are amazing.
The final one relieves the target of most negative conditions. It’s nice when it comes up, but you probably won’t be using this one that often. Shame that it can’t remove negative levels from the raise dead option.

Alternate Class Features
	Biohackers have received alternate class features that replace and/or modify their existing ones. “alt” means alternative class feature. Tl;dr (too long, didn’t read) at the bottom.


Auto-Injector alt - a fundamental issue with Biohacker is that the boosters sound quite nice, but require you to “waste” an action on applying them to friends, while inhibitors not only apply the inhibiting effect, but also actually deal damage to enemies (thus bringing you closer to victory) and even apply all the rider effects from feats and theorems.
The auto-injector alt solves this problem by allowing you to basically prepare your boosters in advance, thus making sure they always go off exactly when they need to and without wasting any of your actions. Fantastic!
This does, unfortunately, completely remove your minor biohacks, thus reducing your battlefield medic role (not like it matters, because you can just shoot buddies with a healing serum to pick them up, or a medicinal that helps deal with the disease or poison), and debuffing role (losing that -1 to attacks isn’t a huge deal, but it does hurt a bit).
The question that this feature raises is what counts as a valid triggering condition? Is it only existing “game terms”, like “getting attacked”, “attempting a saving throw”, as the book describes? Or can you set up something like “when an ally says a trigger word”, or “when an ally thinks of activating it”? This is something you’ll have to discuss with your GM, as there has been no FAQ on it.
Pro tip: the most impactful and notable boosters you may want to consider are: basic boosters, immunology, thaumapathy, genetics. 
TL;DR: while this isn’t a straight up improvement to all biohackers across the board, it is an extremely powerful feature that almost all Biohackers should consider taking.

Ley Line Hacker alt - removes your (extremely powerful) basic biohacks and replaces them with grenades. What this should have been is to fundamentally allow biohackers to use all of their biohacks in a grenade form, thus allowing them to use non-injection weapons. Alas, this is not it, so it kinda sucks.
Note #1: it doesn’t specify you have to choose one of the effects, so you could stack them all together.
Note #2: these are grenades, which means they can miss, scatter, are affected by environmental effects and require you to have a free hand! 
The possible effects are:
-10 movement speeds - unimpressive, considering that you can get the hampering inhibitor theorem that reduces speed by 50% as a part of other biohacks for free, including the minor inhibitors.
Upgrade or downgrade cover AC by 1 point - the change amounts for roughly 5% chance in success rate on the attack/save. Very minor.
FORT save against off-target/nauseated - that’s not bad, actually. Good debuffs. 
Extra damage when dealing energy damage - this one really depends on the party and the initiative roll, because the damage only applies once per round. The extra damage also stinks at low levels (so much so that you’re probably better off not using this at all). That being said, if you have some party members capable of dealing area damage, or just help cooperate and pick the same damage types, you could actually increase your party’s damage nicely, but not greatly. It’s probably a good idea to use the Ready action to throw the grenade just before your other party members act, so as to prevent the enemy from leaving the area.
TL;DR: exchange your universal and powerful biohacks for more gimmicky grenades. 




Fields of Study
There are several exciting fields of study for the Biohacker. Note that you can only use each breakthrough once. You then recover all breakthroughs after a 10-minute or 8-hour rest.
Importantly, it also says that “Each field’s booster, inhibitor, and breakthrough ability follow the rules for basic biohacks unless specified otherwise”, which leads me to believe that inhibitors do not stack with their basic versions.


Anesthesiology:
Booster - pain effects can be pretty annoying, and can actually be pretty common in certain adventures (such as Signal of Screams). This wouldn’t be very notable, if not for the final sentence, which actually allows a character to stack a respectable amount of DR on themselves, which should help soften the blows somewhat. On its own, it’s not going to be swingy. The short duration doesn’t help, either.
Inhibitor - a good bit of extra damage. However, not only is it a poison effect (which makes some creatures immune), it also deals non-lethal damage, meaning that even with powerful biohacks theorem you won’t be able to affect undead and constructs. As such, depending on the adventure, this can either be amazing or situational.
Breakthrough - this is epic. The temporary hit points are actually nothing to sneeze at, and will roughly be able to “tank” a hit from one weaker enemy. The real cream here is the ability to stay on your feet at 0 HP, which, when applied to a very swingy party member (like Soldier or Solarian), can actually help make the deciding final strike to end a dangerous enemy. 

Cybermedicine:
Booster - the limitation to your key ability score really hurts this one. It’s great at very low levels to help “optimize” healing serums. But then at higher levels, when the mystic wants to recover like 56 hit points, recovering 63 instead isn’t going to be that much of a gamechanger. Especially when you consider that you actually have to spend actions to apply the booster in the first place. And it lasts for only a few seconds. Good candidate for autoinjector.
Inhibitor - very niche, as even enemies that have the ability to heal might still just choose to attack. Amazing when it does trigger, but even the basic inhibitors are probably better to help finish the enemy off.
Breakthrough - you have armor, right? Let environmental protections deal with it. The enhancement bonus granted here also doesn’t stack with ring of resistance’s enhancement bonus to saves. 

Genetics:
Booster - it’s a nice little benefit that combines well with the abilities of some other creatures. Helps remove the +40/+20 from Stealth checks for invisible creatures. You’ll be able to deal with targets under the effects of displacement, invisibility, and some other effects much more easily. Likely won’t come up very often, though. Can combine nicely if someone else in the party already has blindsense so you can combo that blind-fight feat with smoke effects that blind your enemies, but allow your party to operate effectively.
Inhibitor - this inhibitor has been strongly nerfed from the, frankly, ridiculously overpowered version it was on release. Now it simply lets you add some extra damage, whenever the creature takes damage of the type specified. 
Most parties won’t be that singular in terms of their damage, so this probably won’t be that powerful. However, there probably still be some intersections, so this inhibitor isn’t entirely pointless.
It does, however, interact well with Acid damage. Not only do biohackers get a caustolance line of acid injecting weapons, but there are also a number of spells that can trigger this Inhibitor often. If you’re running with scaling cantrips, hazard and energy ray are nice. The real cream, however, is the spell caustic conversion, which will be triggering this inhibitor every round.
Breakthrough - ability score damage is so extremely rare that you may play entire campaigns without ever encountering it. It is nice to have in the situations when it does occur, however.
Immunology:
Booster - nice, solid buff that’s good to have if you know the target will be exposed to toxic gasses, radiation, poison and other nasty effects that you’ll likely encounter during your adventures in space.
Inhibitor - if you have a mage in your party - this is amazing. Any penalty to saves that you stack on the enemy makes it more and more likely your mage will be able to completely neutralize the enemy. If you do not have a mage in your party - this is much less useful and is more situational.
Breakthrough - diseases are rare, but extremely nasty in Starfinder. You might not encounter them often, but just enough enemies have them that it may come up. When someone does get infected - you’ll be happy you have this. Note that it only makes the target ignore the effects of the highest stage of the disease. The lower ones still apply.
Neurochemistry:
Booster - if you play in a campaign where this effect may come up often, this is pretty good. But these effects aren’t the most common ones.
Inhibitor - same as the immunology inhibitor. It’s either one of the best tools in your arsenal (if you have a mage party member) or it’s a very situational debuff.
Breakthrough - excellent tool to have (and remember that you have). There are a lot of nasty mind-affecting effects, both as spells and alien powers, and helping free a buddy from them is very useful.
Pharmacology:
Booster - nice way to avoid those nasty bleed crit effects. Obviously useless if enemies don’t put that condition on you.
Inhibitor - encumbered is a good condition, but confusing, when put on enemies. As per the the FAQ, Starfinder enemies do not add Dexterity to AC, so exhausted enemies just ignore that penalty completely. Reducing their speed is… okay, I guess? Could be useful in an all-ranged party that wants to just strafe around enemies. The penalty to STR and DEX checks is super niche.
Entangled, on the other hand, is a great condition that the enemies really do not want to be affected by. It does require a save so will only work if you don’t neglect your key ability score. 
Note that this is both a mind-affecting and a poison effect, meaning oozes, undead, constructs and some other creatures are going to be automatically immune to all effects of this biohack.
Breakthrough - this biohack protects you from a solid amount of negative effects.

Thaumapathy:
Booster - Not that amazing at low levels, when the spells are a bit on the weaker side and spellcasting enemies are rare. But it definitely shines at high levels. Helps more when everyone in the party gets spell resistance of some kind (whether through gear or boosters), so the enemy won’t just target the party members who have no protection (if your GM metagames like that). When fighting against enemies with CR equal to APL (average party level) - it’s basically a ~25% chance to resist a spell. Note that spell resistance doesn’t distinguish between hostile spells and beneficial spells.
Inhibitor - stupidly powerful inhibitor that effectively removes an entire chunk of the possible enemies from the game. The reduced DC and damage is whatever, but extending the casting times is a death sentence, because any damage you take while casting (and any failed saving throw) - immediately breaks the casting and makes the caster waste the spell, as per concentration rules.
While this won’t be that important at low levels, when the spells are a bit more mild, this is an amazing inhibitor to pick up as a part of your second or tertiary field of study.
Breakthrough - if you are the same level as your caster buddies - this effectively lets you return their highest level spell slot once a day. Absolutely amazing breakthrough, as those spells can be very powerful and swingy. Feels great for both the biohacker and mage, too! Obviously useless if you have no mages in your party, but only increases in worth the more mages you have in your party (within reason. Remember you get 1 breakthrough biohack per 10-minute rest).


Toxicology:
Booster - if you play in a game where there’s a lot of wild animals and aliens with natural attacks (such as Attack of the Swarm), this is pretty nice. However, applying it usually doesn’t feel as “good” as applying some other biohacks, as the enemy may just pick a different target.
Inhibitor - sickened is a powerful and varied condition that provides a wide array of penalties which nearly any character can capitalize on. Note that this is a poison effect, meaning constructs, undead, oozes and some other creatures will be immune.
Worse yet, as of the most recent COM errata, in order to apply this inhibitor the target must also fail a Fortitude saving throw, making it significantly less reliable than some other Biohacks.
Breakthrough - same as the immunology breakthrough, but more commonly applied.

Theorems
The “class feats” of the Biohacker class. You get a decent amount of ways to improve your kit and give you new functionality. Biohackers get a theorem every 2 levels.

Note: some theorems have “(studious | instinctive)”, which means the rating of the theorem depends on what the Biohacker’s scientific method.
Second Level Theorems
Ampoule Expertise - interesting theorem, the value of which reduces over time. First of all, you can only create amps once per day and they don’t refresh on a 10-minute rest. Secondly, you get very few of the ones that actually matter (since lv0 ones are very weak). Thirdly, you only get lv0, 1 and 2 amps, and get no access to lv 3 amps. And finally, you have to spent 1 RP to apply it to someone else. The upside is that, unlike normal spell amps, you can inject them as biohacks (meaning you can even do so at range). 
How good is this theorem? Well, it’s okay at very low levels, where this will save you like 300 creds per day on lv1 spell amps, but at the mid-to-high point of the game, this amount of credits will be chump change for you, while occupying a very valuable theorem slot, so this theorem is only ever worth it at low levels. 
Note that since the effects are decided as if you are the caster of the spell, you count your class levels as the caster level, meaning the duration will also be very meh at the beginning and increase over time. 
The applicable spells are:
Level 0: climate adaptation, realign, stabilize.
Level 1: biome adaptation, blessing of youth I, dampening field, extra sense I, flight I, fluid morphism, keen senses, life bubble, might of the ellicoth, mystic cure I, necromantic revitalization I, pyre wreath, remove condition lesser, swim I, helping hands, lifting frame, polymorph I.
Level 2: benevolent synesthesia, blessing of youth II, darkvision, extra sense II, flight II, instant upgrade, invisibility, invisibility to technology, mystic cure II, necromantic revitalization II, perfect recall, remove condition, resist radiation, restoration lesser, spider climb,  swim II, cairn form, polymorph II.
Culinary Expert - cute meme ability, but largely useless.
Cushion the Blow - bludgeoning damage isn’t uncommon, so this is quite epic. Damage reduction scales really nicely!
Field Dressing (studious | instinctive) - this theorem is excellent in the hands of a studious Biohacker, as there aren’t very many ways to recover hit points in Starfinder. Having a simple, reliable way to recover hit points both in and out of combat is excellent. The theorem is much less useful for an instinctive Biohacker, since everyone can take a 10-minute rest to recover all SP. That being said, the standard action requirement and no way to apply this at range makes using this feature in combat a bit tricky.
Hampering Inhibitor - a powerful speed debuff that requires no additional action or resource usage. If you do not have any melee party members - this is amazing and allows you to strafe around the enemy all day long. If you do have melee party members - it’s more situational, but still useful.
Locomotive Adaptation - real nice if you have a predominantly ranged party to get them out of harm’s way, and helps a lot with navigation puzzles and challenges. That being said, there are tech ways of dealing with both problems that are relatively low level, so the value of this theorem is reduced over time. Still, not the worst as far as prerequisite features go and will get some use in your game.
Medication Mastery (studious | instinctive) - the most complex theorem. It allows you to create medications on the fly, for free. The cool thing about them is that many of them have effects that are both hampering and beneficial, which means you can use this as both a support feature and an aggressive one. This is essentially like giving yourself a second, different version of the biohacks feature, as the medications can actually do quite a lot. Better yet, they scale with level, allowing you to create any medication of your level or lower! You can apply them with any of your attacks, same as biohacks, but not at the same time as them. Note that they recover after a 10-minute rest, same as biohacks - so go wild! I’ll try to break them down for you.
First and foremost, both scientific methods get the following three medications:
Analgesic - a healthy dose of morphine. Not something you’ll want to apply to your friends, as it makes the target flat-footed. If the GM decides that it stacks with the basic -2 AC inhibitor, allowing a Biohacker give the enemy -4 AC over the course of 2 rounds (or just with a lucky Full Attack) - then this is excellent. Also helps your buddies deal with pain effects, but should probably only be used out of combat. Do be more careful if you have a buddy mage with pain effects.
Antitoxin - that’s a very good bonus against poisons. Not a bad thing to apply if you know you or your buddy are going to have to make saves against it.
Sedative - a lil’ dab of heroin. Literally just free extra damage. Nonlethal, but it stacks with normal damage. Just make sure to pick your target so you don’t inconvenience the party’s Mystic who just cast fear. Make sure to also keep it in mind if someone affected your buddy with such an effect, as they can probably handle that amount of nonlethal damage in order to get rid of a nasty disabling debuff.
	Then, only an instinctive biohacker gets the following two:
Excitant - some adderall to put some pep in your step. It’s only useful in survival campaigns where you need to perform hard marching and need to look alive during dangerous encounters. The penalty to Dexterity unfortunately doesn’t affect saving throws.
Stimulant - we’re Breaking Bad here. Same situation as the excitant, except it’s hard to use even in survival campaigns, as the exhausted condition is really really bad. If you can somehow get your enemy fatigued applying the lowest level dose to make them exhausted can be fun.
	While only a studious biohacker gets the following two:
Antiemetic - giving your buddy a stronger repeated save against the nauseated condition can be very nice. If they do get affected.
Coagulant - if you do not have enemies that force Reflex saves, but do bleed out your targets - it’s very useful to apply. However, the real cream of this medicinal is the penalty to Reflex saves that you can apply to your enemies. Ask your GM if this would stack with the toxicology inhibitor’s sickened condition. If so, giving the enemy a -4 to their Reflex save before the Technomancer’s Reflex-targeting spell can be pretty epic.
Microlab Jack - the brain augmentation slot has some really interesting options, so clearing it up is quite nice. Quite notably, it just acts as a datajack, meaning this shouldn’t give you ranged access to computers, a-la mechanic’s remote hack. The delay to upgrades kinda sucks. Only consider this if you’re the hacker of the party.
Mobility Enhancement - jumping is pretty niche, and the bonus to tumbling is very minor (a +2 to skill checks basic biohack will be more useful when attempting to tumble most of the time). Good combo with the auto-injector alt.
Morphing Hack - the polymorphing rules are long and varied and go beyond the scope of this guide. You can use this either as a buffing option for you and your party, or as a nasty debuff to your enemies (morphing them into a fire elemental, then blasting them with cold weapons to abuse the vulnerability, for example). Note that you only get one per day, so consider using this with a melee weapon, so you don't lose this ability by missing the attack. Another good thing to remember is that, as a biohack, it scales as a character ability, meaning that the DC of resisting this will actually be quite high. Taking this theorem a second time for another use/form can actually be beneficial, too. 
Painful Injection - more damage good. It’ll apply 2-3 extra damage on every hit for most of your game. It might not seem like a lot, but it adds up and shines in the early to mid game. At the highest levels (15-20) the bonus is too tiny to matter all that much.
Prickly Booster - the damage isn't enough to be dangerous, but can be good at having the creature choose a different target. Shines brighter in games featuring a lot of enemies with natural weapons (such as the Swarm). Good combo with the auto-injector alt.
Speedy Serums - right off the bat - if your GM doesn’t allow you to craft in the field - this is absolutely awful. If they do, however, then you may consider this as an option. You really should decide to either not take this at all, or take both this and the master crafter feat. These feats combined can actually reduce the crafting time so much that you can somewhat comfortably craft serums in the middle of the dungeon. Still a big shame it only applies to serums, and doesn’t even allow you to craft them in batches. Either way, make sure to track the list of serums that you can craft (maybe have a list somewhere close by), as getting the right serum at the right time can be a real clutch moment.
Note: the breakdown of every available serum is in the Gear description!
Strange Anatomy - a solid pick for melee Biohackers. Not so good for ranged builds, as they won’t be hit as often.
Telepathic Boost - only 30ft and no language sharing. Gimmick.
Toxic Skin - too niche, but in games that feature a lot of enemies with natural attacks this will be a great pick for melee Biohackers.
Treat Condition - your actions can probably be used in better ways, unless the duration is very long. In those scenarios this is pretty good. Prerequisite for improved and greater treat condition.
Treatment Mastery - situationally nice, if you run into poison/disease a lot. Probably isn’t your first theorem pick.
Eighth Level Theorems
Advanced Locomotive Adaptation - fly speed is excellent to avoid ground targets and chase down flying ones, and having it as a party-wide thing for more than an hour is excellent. Burrow speed is arguably even more appealing, as there are no super easy and convenient ways to gain it. Not only does burrowing give you total cover (which can be borderline broken with shot on the run feat), but also allows melee party members to enter someone's threatened square without triggering AoOs (since they have total cover underground). You do technically need ways to see past your obstacles to spot enemies moving on the ground, since they have total cover from you, too.
Arms Expert - if you’ve gotten to level 8 without gaining full weapon specialization in other ways (through feats or similar) - this should be your first pick at level 8. If you chose to learn the weapon proficiency feat and the versatile specialization feat in order to add full level to damage early - then you should obviously skip this.
Elongation Mutation - extremely useful if you have any melee party members, as increased reach not only helps them trigger AoOs way more often, but also squeeze more damage out of their abilities (especially relevant for cleave Soldier builds and Vanguards). Obviously do not pick this if you're in an all-ranged party. Interacts super well with auto-injector alt.
Enhanced Senses - being able to see invisible creatures is useful, but blindsense with a range of 5 feet is borderline useless. The penalty to Fortitude doesn't help much, either. Only consider this if there's no one in the party who can pack a see invisibility spell gem.
Far Injection - is 60-80 ft. range not enough for you already? Has a fun interaction with sniper rifles, as your Biohacker can have an absolutely nutty 2250 ft native range increment with the wraith-sting rifle. Combine it with other mods and you can basically snipe people while sitting in the neighboring country.
First Aid Expert - not a giant boost, but if you're the main medic of the party - this can actually be really nice.
Grounding Inhibitor - clumsy fliers can't hover in place, so they'll be forced to move, which they do with a -8 penalty on all checks. While not exactly a complete solution to the problem of flying enemies, it is a nice debuff to have, especially if you have flying melee party members who can make use of the attacks of opportunity. It's solid. Notably works even with minor inhibitors.
Improved Treat Condition - unlike treat condition, this theorem actually allows you to deal with debilitating conditions that can completely take a character out of the fight. You might not run into them every day, but when you do - you’ll be happy you had this. Gets better at higher levels, since those conditions become more common.
Powerful Biohacks - an excellent pick to make the pharmacology and toxicology inhibitors apply to far more creatures. Interestingly, affects the tranq dart, too.
Stable Biohacks - this can be pretty good to give to your buddies so they can load some booster into a cheap low level injection weapon. The issue is that, unlike you, they won’t be able to automatically hit their targets. So there is a chance they’ll just miss it. There are situations where this can be very nice, but you probably shouldn’t bother.
Sure-Step Booster - pretty niche, unless you often fight on difficult terrain. Interacts well with auto-injector alt.
Technological Biohacks - d-did they just forget that powerful biohacks theorem exists? This is the same thing, but worse. I am genuinely baffled by this theorem.
Tranq Dart - very very fun and thematic ability. Sure, you only get one to two per day, but this thing makes the enemy fully helpless. This means the target is eligible for Coup de Grace, allowing your or a buddy to instagib 400 HP worth of enemy meat. 
Treat Radiation -  a rad-out serum is cheap and already helps with radiation quite a lot. Now radiation sickness, on the other hand, is an extremely evil bastard to deal with. If your GM is ruthless-enough to use those Radiation effects - this might quite literally save someone's life. Or just remain completely unused in your feature list.
Fourteenth Level Theorems
Ampoule Mastery - now this is quite different from the previous theorem. The ability to create a lv3 amp is nothing special, it's only 3k (total chump change, as the wealth by level at lv14 is 333,000 creds). But the lv18 ability to create a lv4 amp is totally unique and cool, making you akin to a half-caster of olden days.
The applicable spells are:
Level 3: accelerated adaptation, blessing of youth III, displacement, extra sense III, flight III, fluidity of form, haste (just buy a haste circuit), mystic cure III, necromantic revitalization III, nondetection, physical stability, remove affliction, resistant armor lesser, sharpen senses, swim III, polymorph III, tongues.
Level 4: blessing of youth IV, death ward, flight IV, invisibility greater, mystic cure IV, mystical aegis, necromantic revitalization IV, remove radioactivity, restoration, swim IV, hateful visage, polymorph IV, polymorph mass.
Bleeding Biohacks - it's free extra damage. Spread it around with a full attack. Works with minor inhibitors, too.
Energetic Booster - awesome and versatile. In theory. By this level, if your targets can benefit from those feats - they probably already took them.
Greater Field Dressing (studious | instinctive) - even more healing for studious Biohackers, which is awesome. Still decent even for instinctive ones.
Greater Treat Condition - removes extremely powerful conditions. By this level these conditions likely have very long durations, too, so you might be saving the party from a TPK by using this at the right time. And, since it affects a very wide array of conditions, you’re bound to use this theorem or the ones preceding it very often during high level games.
Iron Gut - immunity to a single condition, and nauseated can still mess you up. It's alright. Fortitude is our strong save, so we'd hope to succeed on these saves in the first place.
Liquid Bravery - not too bad if you’re fighting terrifying creatures. At this level they do exist here and there. But still, niche.
Ooze Form - don't sleep on immunity to critical damage - this is probably the biggest benefit of this theorem, equivalent to 100% fortification (minus the crit effect immunity). The rest of this ability largely depends on whether or not you are a melee biohacker. If you are - this is an easy way to flank and increase you attack of opportunity area. Being unflankable also helps a ton. Compression can be situationally useful, too. The ability to split can be dangerous, however, if the enemy is using AoE weapons/spells.
Poison Extraction - you probably won't use this often, but it can be cool when it works, as high level poisons can be very deadly. Annoyingly, you can't reuse the poison if you succeeded on the first saving throw against it. 
Feats
Feats make up a very important part of character generation. There are a lot of them (235, as of right now), and some are extremely situational and will be either really good or really bad in different kinds of games, making them impossible to rate objectively. Another thing to remember is that feats aren’t a unique part of the Biohacker chassis, and are generally going to behave the same in the hands of every class. I’ll just highlight the feats that I think are going to enhance the Biohacker chassis, deal with some of the class’ shortcomings, create interesting builds or are just very useful. I’ll also be excluding all spellcaster feats.

Accelerated Recovery - it’s a neat little ability to pick up if you don’t have a dedicated healer in the party and your GM tracks HP recovery rules very accurately. Normally it’s 1 HP per level for an 8 hour rest or 2 HP per level of bed rest for 24 hours. Thus, if you took a beating in the last dungeon, you can recover a bit faster. That being said, most adventure paths give enough free time to rest to full HP between adventures, which limits the feat’s usage.
Adaptive Fighting & Versatile Fighting - Biohackers aren’t Soldiers, so getting additional feats during a hard boss fight is nice. The fact you can only do this once per day sucks a bit. Versatile Fighting makes getting these feats even easier and allows them to be active pretty much most fights during the day. Additionally, this feat fits the adaptive fighting TIM for space combat engagements.
Adaptive Upgrade - studious biohackers may have the Intelligence investment to get this, and it’s a great feat. Easy way to get some versatility out of your armor upgrades. Even if you don’t use many armor upgrades this will not be hard to invest into, since this applies only to upgrades half your level, which means they will be pretty cheap for you. Targeting computers, ghost armor, juggernaut boosters, jetpacks, force fields, phase shields, brightlight projectors and agility enhancers are just some examples of very nice upgrades to consider using with this feat.
Advanced Melee Weapon Proficiency & Longarm Proficiency & Heavy Weapon Proficiency & Sniper Weapon Proficiency & Special Weapon Proficiency - advanced melee weapon proficiency and longarm proficiency makes you eligible for both weapon focus feat and versatile specialization. The former makes you noticeably better in combat, while the latter lets you add your full level to damage of your non-small arm/non-operative injection weapons, thus freeing up your lv8 theorem spot, as you don’t have to take arms expert. 
Sniper weapons aren’t amazing, as the only published injection sniper that deals damage is tagtech rifle, which is fine, but it’s the only weapon of its type and so isn’t recommended.
Avoid heavy weapons, as (currently) there are no injection heavy weapons.
Special weapon proficiency lets you pick up versatile specialization to add full level to damage of grooved shuriken. A very weak option. Better to take advanced melee weapon proficiency and put returning and throwing fusions on it.
Ambuscade - getting any untyped attack bonus for a ¾ BAB class is always great. I hope your party is packing Stealth.
Amplified Glitch - gives a very nice penalty to a decent number of targets. The DC is high, but a well-specced Biohacker can handle it, especially with a racial bonus to Computers.
Pro tip: remember that this gives penalties to ability checks and skill checks (e.g. sense motive), not to mention it looks intimidating as hell, allowing you to creatively use it in social scenarios as well.
Antagonize & Quick Quip & Goad & Clever Retort - series of feats that allow one to use Intimidation or Diplomacy in combat:
Antagonize can be a cool option for a tanky build, especially with an auto-injector alt and a booster that punishes enemies for attacking you (such as prickly boost or toxic skin). Will be pretty tough to do at a low level, since you’d need to balance your main attacking stat, CON for survivability, key ability score for hacks and Charisma to succeed at a fairly high Antagonize DC. At higher levels you can stack up quite a lot of bonuses to Intimidation, however, to make this work. 
Quick Quip is basically the Diplomacy version of Improved Demoralize and Improved Feint feats. It’s pretty good and, since it lasts until the end of your next turn, gives you good chances of capitalizing on the penalty. Unfortunately, there’s no way to share the debuffs with the party.
Goad is a no-brainer if you’ve already taken antagonize or quick quip, as it’s only a swift action to extend the rather delicious effects they grant.
Clever Retort is useful if you’re fighting several enemies and want to spread the penalties more widely, but since it happens in reaction to another enemy outside of your turn, it means that you’ll only get 1 turn worth of actions against them, rather than a standard action + 1 extra turn you’d normally get by using it as a move action.
Barricade - this creates partial cover, meaning it gives the creature behind it +2 to AC and +1 to Reflex saving throws. Considering this uses a move action and has no daily limitation of use, this is awesome for any ranged Biohacker. Use it often. Use it well. The only reason this isn’t blue is because you can probably already take cover using the environment around you.
Blind-Fight - as usual, when combined with effects that produce concealment, this can be a major defensive boost to your party. Not something you’ll be able to use often without cooperating with the group.
Bodyguard & In Harm’s Way & Shelter Ally - a trio of defensive support feats. 
Bodyguard if you have good protection and haven’t skimped on your Constitution, this can be nice to keep a more fragile party member alive in the melee. Works best if you have more melee party members, as it means more adjacent creatures.
In harm’s way is pretty great if you’ve already felt the need to take bodyguard. With the right Constitution you can probably tank one or two hits for the party’s melee Technomancer.
Shelter ally is a must-pick feat if you want to play a bodyguard build as a Large race, as this will (often) allow you to both flank enemies and protect your buddies. That being said, quite a lot of enemies will be larger than just Large, limiting this feat’s power somewhat. 
Cleave & Great Cleave - cleave is amazing when it works. Great cleave is just way too niche to be used reliably. You likely want Reach if you pick this one up (either through weapons or race). If you plan to multiclass into Soldier this is a must-have, since combining it with spinning cleave feat boost is genuinely one one of the strongest combos in the game. The reduced AC can be dangerous, so think well before using it, as it’s a high-risk, high-reward gamble.
Climbing Master - it’s okay if you plan to climb a lot, but why bother when you can just buy a jetpack?
Close Combat - great way to get extra protection in combat.
Combat-Trained Mount & Mounted Expert - alright, mounts are really cool, but are very hard to rate. They are a great way to enhance your mobility, add some damage, and get some unique movement options. However, they also can cost quite a lot of money, are usually quite big and uncomfortable to use in tight quarters, hard to keep stealthy and mobile, and are awkward to use in zero-G combat. As such, the quality of these feats can range from absolute garbage, to fairly decent, to damn cool, depending entirely on what kind of game you are playing.
Keep in mind that taking any damage while mounted makes you fall off the mount, unless you use a reaction (DC5 survival check) to stay mounted.
Combat-trained mount allows you to effortlessly use your mount in combat. Normally using them in combat requires a DC20 Survival check “for each action you attempt to take, or have your creature companion take”. DC20 survival check is pretty damn high for us, as we likely won’t be having the highest Wisdom and able to get such checks reliably only by level 13-ish, with feat/race/wisdom investments. That’s quite a lot, but some games (e.g. Devastation Ark) literally start at such a high level, at which point this feat is literally useless, aside from as a prerequisite for the mounted expert feat.
Mounted expert simply makes it so that you don’t fall off your mount because of damage, kind of freeing up your reactions a bit, which is nice for melee builds. 
Connection Inkling - not a bad feat for instinctive Biohackers, allowing them to pick up a decent number of uses of low level spells, if you have the Wisdom for it. Spells to consider are Wisp ally can be cool to use for the supportive fire benefits, build trust, memory lapse and charm person are excellent for social interactions to shore up our likely eh Charisma, defrex hardiness is a very potent buff to get for free (better yet - it scales with your overall character level, not mystic level!) and detect thoughts. 
Constant Alert - winning initiative is nice, but a single reroll per day kinda sucks. Going first is pretty useful as a Biohacker, but you may just keep this feat in mind for the really high levels when you don’t have anything else to take.
Coordinated Shot - if you have even one ranged character in the party, at least one melee character should take this. Hopefully it’s the Soldier, but anyone will do.
Cosmic Truth - interesting and powerful pick for instinctive biohackers. Decent option to use after you finished applying all of your Biohacks.
Craven Ploy - melee Biohackers are in a weird position where they’d might want this for survival, but are also probably in a flanking position, and not adjacent to a friend. If there are three melee characters in the party this is a bit more interesting. Then again, Biohackers usually have decent survival abilities, so you may rely on other things to survive.
Creature Companion Adept/Expert/Master/Virtuoso - alright, companions. They definitely deserve and need their own guide. They are a big feature introduced in Alien Archive 3. For some classes (read: Soldier) they are an extremely powerful and probably overpowered featline. They can add a lot: extra damage, flanking, unique abilities and a warm target for enemies to hit. And the system support for them actually ain’t half bad: the damage is respectable, the attack bonus is just fine (if you can afford keeping them up with your level), and they heal very efficiently (recovers half its max HP any time you use Resolve to restore stamina during a 10-minute rest).
However, most classes are probably too feat-intensive to use them efficiently. Biohacker might actually be one of the exceptions. Ranged Biohackers don’t really need any particular feat too much and can afford those feats. Melee Biohackers may not need more than heavy armor proficiency, so this can be a fine option, as they can benefit greatly from the free flanking the companions can provide.
Finally, companions are an extremely powerful roleplaying tool. Give a good thought about how you flavor them up, your and your party’s connection and relationship with them, what sort of things they do for the party to even remember they’re there. Think about what a companion of a sci-fi alchemist would look like.
Adept feat is pretty much just a flanking tool. The range is a bit too close for ranged Biohacker’s comfort, too.
Expert feat is just excellent, and really the minimum required investment if you are interested in companions, as it provides you an extra way of dealing damage as a move action. Don’t forget they get a move action before any action you grant them, meaning if you use a move action to give them a standard action they have both a move and a standard action. ‘Ery noice.
Master feat makes them pretty much independent from your character range-wise, and essentially gives them independent actions, meaning you can combine them with stuff like improved demoralize. Full attacking with them is usually a bad idea, due to the massive -6 penalty.
Virtuoso feat is alright. It’s good if you have a very strong companion, but you can likely skip it in favor of some other feats, as a master companion is good enough the majority of the time.
Deadly Aim - with your BAB you probably want to skip this. Biohackers want high to-hit to land those Biohacks.Check out this thread for more information.
Deadly Boast - high Charisma price and Bluff requirement. Underwhelming. But some Biohackers could have the stats to pull this off by higher levels.
Defensive Roll - if you got Acrobatics as a class skill somehow, and have a good Dexterity score, this is actually really good, as it helps you survive both in melee and range. This is honestly okay even with middling Acrobatics, as even if you just put ranks in it without the class skill bonus, your Reflex save will be lower pretty much all the time. If your acrobatics suck, obviously skip this hard. However, take care when you use it, as it makes you Staggered next round. 
Defensive Striker - good feat to increase your defenses. Not quite great-enough to warrant picking Hobgoblins over every other race, but still very nice.
Deflect Projectiles & Reflect Projectiles - this is a neat featline for a melee Biohacker looking for new feats to pick up after getting their core stuff already. The +5 bonus is “good enough” to succeed most of the time. 
Reflect projectiles is kinda meh, as a -4 with your BAB is pretty bad and it doesn’t apply your weapon focus bonus.
Pro tip: grab a weapon (or fusion) that deals both physical and energy damage. That way you’ll be able to affect both energy and kinetic projectiles with one weapon (according to Starfinder’s Lead Designer)! Alternatively, if you can afford the free hands, you can just keep a weak low level energy/kinetic weapon in a free hand for deflecting purposes.
Diehard - the situation must be really grim to use this. I suggest only picking it up after you’ve already played the game for a bit and can see that your GM is just brutally cutting everyone down all the time and when you actually know you’ll get to use this
Dire Straits - same as diehard.
Disease Adaptation & Disease Rejection - you probably have the Fortitude to handle diseases. Disease rejection is nicer, but not worth picking up due to its prerequisite.
Dispelling Strike - melee Biohackers (especially instinctive) may just have enough ranks in Mysticism to be able to take this. It’s pretty nice. Don’t forget that you do not apply any damage with this attack, which means that you can use this to dispel some nasty spell from your fellow party members.
This would have been blue, except if you’re not extremely tight on money or augmentation slots, you can just buy a dispelling hand and not waste a feat on this, except it requires an attack roll.
Dive Bomb & Improved Dive Bomb - duo of feats for flying melee builds (ranged should ignore completely).
Dive bomb this can really help flying Biohackers to stick into the melee. It helps to avoid the AoOs of creatures on the way to your target, too!
Improved Dive Bomb is just not great. Biohackers aren't combat maneuver specialists, so you should leave this one for your martial buddies.
Dive for Cover - great way for ranged Biohackers to deal with their bad Reflex save. Melee Biohackers probably do not want to risk being prone, unless you got Moxie or something similar to help you get up fast.
Double Tap - this is what makes small arm builds viable. Builds that don’t want to use longarms may find this quite attractive. Versatile specialization would allow you to add full level to longarm damage, which is more damage overall.
Effortless Aerobatics - Together with Dive Bomb can grant good air mobility options for melee biohackers. Ranged builds can make do without this.
Enhanced Resistance - has been nerfed in the 3rd printing of the Core Rulebook (you now can’t pick Kinetic as a damage type, but have to pick either slashing, piercing or bludgeoning), but still remains a very strong pick. Sure, your BAB isn’t the best, but piercing damage is common in both ranged weapons, melee weapons and natural weapons. It and Fire damage types are the best, most common picks. But, obviously, if you do some adventuring in the winter tundra, or some specific elemental plane, there may be better options.
Extra Resolve - Biohackers don't get that many essential options that require resolve, so this is probably overkill. A lot of higher level items can be recharged with a Resolve Point, though.
Far Shot - injection weapons have pretty good ranges already, so this will be redundant in most games. If you’re using small arm injection weapons and you know your GM likes using big battlemaps - this can be cool.
Fighting Balance - not that amazing for melee builds, but a pretty big gamechanger to ranged builds, giving them essentially a free +4 bonus AC against ranged attacks. If you have kip up, improved kip up or moxie this becomes really good, as it means you’re not even limiting your mobility all that much by dropping prone. Biohackers are also not a very full action-intensive class, so you’ll likely have the free swift action to drop prone or stand up to spare.
Fleet - gotta go fast. Considering the tech ways of boosting your speed, this isn’t super necessary. Heavy armor-wearing characters would want this, but can’t benefit from it.
Focused Sense - can be used in combination with a genetics booster to get a clutch blindsight if you don't have it through tech means. Or you could just buy an enhanced senses II spell amp and keep it in your pocket.
Frightening Injection - fun ability made entirely irrelevant by improved demoralize. Only pick it if the other feat is banned.
Grab Attention - something melee Biohackers should seriously consider, if they have the Charisma for it. It’s easier to gain than antagonize (don’t need 5 diplomacy ranks), doesn’t require an action to apply at all (not even a reaction!), rewards you for doing something you’d be doing anyway (poking fools) and has the exact same DC. Uh, oops? Classic Paizo-patented powercreep (™). The only disadvantage is that it lasts only for a single round. Then again, with your Charisma and bonuses to Intimidation - so will antagonize, most of the time. Same as antagonize, combines extremely well with an auto-injector alt and prickly booster or toxic skin theorems. 
Note that the DC is very high, so you definitely want to squeeze out any bonus to Intimidate that you can get.
Great Fortitude & Improved / Lightning Reflexes & Improved / Iron Will & Improved - as a Biohacker you get 2 weak saves: Will and Reflex. These feats are a great way to make them work a bit better. The Reflex ones especially, since it’s likely that those saves will be the lowest. There are way of getting rerolls through other means (racial features, some pieces of gear, or other feats), but none are as reliable as the Improved version of these feats. That being said, they’re very boring options, and don’t allow you to do anything new, necessarily, so you probably will be okay if you just pick one-two of these for your lowest save, so you’re not absolutely awful at them.
Grenade Mastery & Cook Grenade & Ricochet Grenade - grenades are weird. Some of them are really nice, most of them are pretty bad. The DC scales with Dexterity and item levels. They’re pretty expensive (but have received significant cuts in price as of the most recent errata), but usually have cool effects. Not to mention, you’re proficient in them, so why ignore this potential edge?
So with all that, are these feats worth it? The answer is… maybe. With the new(er) additions to the game, there is feat support to increase their DCs significantly, making you get more bang (hah) for your credits. If you have a high Dexterity score, the utility and AoE damage the grenades can provide are notable. And if you don’t rely too much on your weapon, you might have the credits to spare to buy some of them. 
Grenade mastery increases the DCs of all grenades, especially lower level ones. If you have already decided to use them, this is pretty great, as some of the nastier effects are more likely to proc.
Cook grenade is the thing you really want as a grenade user. Granted, it uses a full action, but the increased DC is a no-brainer, especially when combined with grenade mastery.
Ricochet grenade sounds like a really fun feat, but how often do you try to do that, anyway? Better yet, how will a GM make a ruling that you can’t do that normally (except maybe requiring a harder check of some sort)? It’s just weird.
Heavy Armor Proficiency - light armor is usually even better than heavy armor for characters who maximize their Dexterity score. However, for characters who want to dump their Dexterity (read: melee Biohackers) - this is a godsend. Heavy armor barely uses Dexterity and provides very solid protection. If you do have high DEX, however, ignore this feat completely and just keep using light armor.
Improved Combat Maneuver - Biohackers don’t have full BAB so hitting that KAC+8 will be tricky, but not impossible. If you, as a melee build, really want to get some features here just to further complement your debuff game it could be decent, but you usually also need gear support. Unfortunately, you’re limited to injection weapons, so getting the good stuff will be hard. Just use your Biohacks instead.
Improved Critical - critical hits happen too rarely to invest into them. And you can just try to pick crit effects that require no saving throws. Not to mention by default the only crit effect your weapons will have is Inject DC +2, which doesn’t require a save by itself.
Improved Demoralize - this alone makes investing into Intimidation worth it. Absolutely fantastic debuff, providing a wide range of debuffs and helping pretty much the entire party. Hope you have the Charisma for it.
If you combine it with deadly boast and some of your inhibitors (and the GM allows for the penalties to stack) you can increase the failed save chance against the party’s spellcaster from 35-60% failed save chance to a good 55-85%, which is not insignificant.
If your GM bans feats from adventure paths, consider frightening injection.
Improved Feint & Greater Feint - feint makes your opponent flat-footed for your next attack as a standard action. On its own it’s not the best for Biohackers, but making a few investments into these feats isn’t the worst option.
Improved feint turns this bad combo into a pretty good one. Nice way to reduce the enemy’s defenses for a solid hit.
Greater feint makes the enemy flat-footed fully, with no strings attached. That means your entire party will have an easier time hitting them, and the enemy has no AoOs, meaning you can use your pistol sidearm to shoot friends up with beneficial biohacks around the enemy as much as you’d want. That being said, if you have an Envoy or Witchwarper (who probably want to take this feat more than you) or an Operative in the party - you probably want to completely skip this.
Improved Initiative - going first is always nice, especially if you have hampering inhibitor.
Instant Crater - can be okay if you use grenades a lot. Definitely not your first pick.
Jet Dash - can be fun to have in low level games, but there are simply too many ways to get means of proper flight to benefit from increased jump distance. Running is also pretty niche, since most battlemaps won’t even be that huge.
Kasathan Battle Dance - despite having “Kasatha” in its name, this feat isn’t limited to Kasathas, or even four-armed creatures. It is a very cool way to carefully and safely escape a hairy situation for ranged characters. It works especially well for characters who always have two hands free, which probably won’t be happening for Biohackers, unless you are a race with more than 2 arms. Additionally, this combines well with parting shot, allowing you to basically ignore AoOs triggered by ranged attacks.
Kip Up & Improved Kip Up - there aren’t that many effects that will be knocking you prone. Melee characters will probably be knocked down a bit more often than ranged ones, too. And unlike Operatives and Vanguards, we don’t get uncanny agility to make use of fighting on the ground. Great combination with fighting balance for ranged builds.
Laugh at Danger - you are considered your own ally in Starfinder, so this is pretty much a party-wide +2 to AC, which is great. It’s probably a bit too niche for ranged Biohackers who probably won’t be getting hit that much, but melee ones will definitely benefit a lot from this and be able to use this one quite a lot.
Living Ladder - you’re using injection weapons, not punches.
Lung Puncture - almost every single Biohacker build uses piercing weapons, and uses them a lot. This is a great pick. Just make sure to clear up with your GM if, when using a full attack to shoot your party member if this feat can also be ignored as a part of injection expert.
Lunge - neat feat to pick up for melee builds in a melee-intensive party, allowing for fighting in two rows while staying safely behind a buddy’s back. Also allows three melee party members to all benefit from flanking. Can be cool when fighting against opponents with reach to poke at them without needing to trigger an AoO to approach closer (unless you have spring attack).
Positive Conduit - okay for low level games, but becomes largely pointless as levels go along. When you have like 20 HP then restoring an extra 3 HP is decent. But when your HP is closer to 200, restoring like 6 extra HP is a drop in the ocean. The fact that you need a 10-minute rest to use it again is like a slap in the face at those higher levels.
Psychic Power featline - it’s mostly pretty mediocre divination spells, the effects of which you can usually achieve through technology.
Master Crafter - if your GM doesn’t allow you to craft items in the field - this is garbage. If they do - reducing crafting time of some items from 2-4 hours to 1-2 hours makes it much easier to use in dungeons and whatnot. But the need is going to be pretty niche, especially since if you can wait for 2 hours, you can probably wait for 4 hours, as well. However, with the speedy serums theorem, this actually becomes much nicer, allowing you to cut down the crafting time pretty severely to the point that crafting just the right serum at just the right time becomes a viable solution to many problems. Make sure to keep some UPBs in your back pocket.
Medical Expert - it only recovers HP equal to the target’s level or CR (+ your INT score if you beat the DC by 5 or more) with a DC 25. Pretty anemic (hah) and bad in the early game, but can be cool to have in the later stages of the game for a little pick-me-up, as healing serums become more and more expensive, while medpatches keep costing only 50 credits a pop and you’ll be beating the DC by 5 pretty much every time. If you picked up the medic archetype, this actually becomes quite decent at level 9, since it is a noticeable boost to how much HP you restore with Treat Deadly Wounds.
Note that instinctive biohackers don’t get to add WIS to the total healing when beating the DC by 5, since their scientific method only improves the skill check, not everything else related to Medicine, which might be an oversight.
Note that you can add all the bonuses you have to Treat Deadly Wounds with this feat, such as through the first aid expert.
Memorable Coercer - if you did spec into Intimidation, this can be a very powerful tool in narrative games.
Memory Access - cool way to get insight bonuses to a lot of skills. Might be worthwhile for studious Biohackers, since a lot of recall knowledge checks are Intelligence. That being said, the identification part is largely useless to us, thanks to the microlab being a nat 20 on the identification check.
Mobility, Sidestep, Improved Sidestep, Shot on the Run, Strafe, Parting Shot, Spring Attack -  putting the main “mobility feats” in one chunk, since they all do basically the same thing - allow you to be more mobile on the battlefield.
Mobility on its own is pretty good early on, as you can just walk away from threats as a move action and then blast them with your standard action. Remember that this doesn’t apply to AoOs triggered by ranged attacks. It helps ranged Biohackers run away from threats with Reach, while allowing melee Bihoackers to approach them slightly more safely. Though it’s still a gamble.
Sidestep is used mainly to get out of a flanked position, get into a flanking position and able to full attack, escape one of the threatened areas if you’re surrounded by two opponents, or to get into position for bull rush to get an enemy into a dangerous zone. It’s not bad, but the fact that it uses reactions makes it a bit ehh, since you want those potential AoOs. This is dead red for ranged Biohackers.
Improved Sidestep makes it easier to walk away from an enemy who missed an attack on you. I can see the point, but this will likely barely come up. Not that great for ranged Biohackers, either, but more useful than sidestep, since this allows you to use your reaction to step to the outer threatened area of a creature with reach, and then use your normal move action to make a guarded step outside of the threatened area.
Shot on the Run is the Run ‘n Gun feat. Very nice way to maintain a defensive position between shots.
Strafe is a capstone of mobility for a ranged build, allowing you to fly between covers and shoot at the same time. Note that the penalty to attack rolls is flat, this isn’t a full attack, so gunner harness and multi-weapon fighting feat won’t be reducing this penalty.
Parting Shot is pretty nice for ranged Biohackers. If you already made such a big investment, grabbing this to get away from enemies’ melee range is pretty good.
Spring Attack is extremely useful for melee Biohackers, since this is how they get into range of strong creatures with Reach. 
Momentous Attack - good way for melee characters to position themselves better. Probably won’t be your first pick, but getting something that just gets you free actions for doing what you already were doing is great. Note that it doesn’t use a reaction!
Multi-Weapon Fighting - can be a fun combo if you want to increase the odds of applying more biohacks with more shots. That being said, thanks to the gunner harness and bipod (which are, frankly, overpowered items) - this feat is made largely irrelevant.
Mystic Strike - you don’t have spellcasting and getting spellcasting for this feat isn’t worth it. Just buy a fusion.
Nimble Moves - neat ability and works for magical difficult terrain. Frankly, the ability to step in difficult terrain is probably the best benefit of this. Works a bit better if you have a party member who’s creating such terrain often.
Penetrating Attack - enemies in the lategame get a lot of resistances and damage reductions, so having ways of reducing them is an excellent passive buff.
Powered Armor Proficiency - requires proficiency in heavy armor as a tax. The advantage is that it allows you to get monster Strength while not having it above 13 on your character personally, thus making a faux-hybrid character who can both shoot well at range and break some skulls in melee. Rather awesome for some (melee) characters and builds.
Quicker Trickler - just load up your injection sidearm with healing serums and pew-pew-pew them from range.
Reality Glimmer - get yourself some fun Witchwarper spells. Churn fluid and grave words are fun, charming veneer can help our social stuff, detect thoughts is good for skullduggery.
Sacred Strike - Pretty niche way to avoid some DR. Common in outsiders, but difficult to get a lot of use out of it, unless your game is really focused on fighting outsiders. 
Scurry & Underfoot - interesting positional abilities for small, dexterous characters. Ask your GM if and how the creatures give you cover when you’re in their space.
Scurry allows you to stand in your buddy’s spot. Compression rule is: “The creature can move through an area as small as one-quarter of its space without squeezing or one-eighth its space when squeezing”, which is fun, as it allows your ysoki to crawl into really small pipes. Probably smaller than the width of their own gear. Kinda useless for ranged builds, but melee ones can flank enemies with just three melee party members.
Underfoot allows you to attempt a fairly difficult Acrobatics check to get into an enemy’s space. Enemy AoEs will be impossible to place without also damaging the foes in who’s space you are and the enemy has serious debuffs put on them. However, failing this check is really bad. The feat is nice for DEX melee builds with Operative weapons. The issue is that the enemy can just take a Guarded Step out of your range and be completely fine and safe, meaning this is only really nice to use against enemy mages/ranged targets, as even if they take a guarded step - you’re still there to shank them in their shins, giving you a lot of AoOs. Then again, any melee character can get the same benefit with step up and strike.
Shield Block - cool to have when it’s relevant, but buying both armor, weapon and shields of a high level will be tricky.
Shield Proficiency - shields are pretty damn awesome. The disadvantage is that most of them have very low DEX caps, meaning lightly armored Biohackers will likely only reduce their AC with them. If you’re a melee Biohacker, or just don’t have a very high DEX cap and/or use heavy armor, and/or have a hand free - shields are an easy way to get +1 AC. Which is always cool.
Skill Focus - get better at some skill. Don’t forget that the insight bonus doesn’t stack with your scientific method.
Skill Synergy - get two class feats, or improve an existing skill. Pretty awesome for instinctive Biohackers to select two skills they apply their free ranks to, if they’re not class skills. That being said, we already get a lot of class skills for all kinds of scenarios, so this probably isn’t all that important. Don’t forget that Insight bonuses do not stack.
Sky Jockey - like fleet, but after you get a jetpack.
Slam Down - you’re not a Soldier. Stick to injection weapons. 
Slippery Shooter - if your frontline party members can’t keep the enemies at bay (or don’t exist at all, in a ranged-only party) this is a fairly nice buff, but you probably want parting shot, instead.
Solid Stance - This won’t be used very often and doesn’t help when dealing with heavy ranged fire. Get kip up, instead.
Spellbane - decent option, providing protection against a whole lotta nasty. Note that it doesn’t work on Supernatural Abilities.
Spellguard - only works on adjacent targets, and you’re probably better off dispersing so as not to get shot by AoE spells, instead of grouping together.
Spell Penetration & Greater Spell Penetration - we don’t get spells.
Stand Still - good ability, but your BAB will make you miss this very often. Go for Step Up & Strike, instead.
Startled Scream - funny, but gimmicky. The penalty condition isn’t very nice, either.
Step Up & Step Up and Strike - helps you stay on your opponents’ toes. Obviously completely useless for ranged Biohackers, but melee builds can make use of these.
Step up helps you keep an enemy in melee reach, but not much aside from that. It’s okay to have, but really it’s just a tax for the next feat.
Step up and strike is the really nasty one. Basically this means ranged opponents and spellcasters hate you more than anyone else, as you can keep bonking them over the head any time they try to do anything. While you may not be using this feat more than once per fight, the fact that the enemy knows you can use it will give you a major tactical advantage, forcing the enemy to do unoptimized actions.
Strike Back - nifty if you fear AoOs. But too niche. Go for spring attack, instead.
Tactful Advisor - just a solid feat all around. You'll likely be aiding others a lot, have the wide-enough skillset to do it often and beat the DC20 reliably.
Teamwork Feats - I wanted to have them all here, all in one place, for ease of rating. Talk to your party before taking these, just to make sure you have at least one other person who takes it, in order for both of you to enjoy the full benefits of this choice:
Timely Coordination - helps your buddies with unwieldy weapons a lot, plus, when dealing with an extremely limited resource like a breakthrough or superserum - you really want to take any bonus to attack that you can get. Aside from those circumstances, you’ll probably be full-attacking most of the time, anyway.
Above and Below - useless for ranged builds, but it’s a no-brainer for melee Biohackers. You get more damage and positioning becomes much easier. Make sure to talk it out with other melee party members.
Back to Back - you don’t want to be flanked. A bit more decent with a more dedicated “tank” in the party.
Last-chance Grab - too specific, you probably won’t even get to use this in a game more than once. 
Stand Strong - if you picked up stand still - this is likely worth picking up as well, especially if you and a buddy are trying to form an impassable wall to protect your backline. 
Tandem Feint - useless if you have an Operative in the party, but if you don’t - this is actually pretty sick if you have the Charisma for feinting.
Tandem Maneuver - you’re not a combat maneuver build and get little from this.  
Target of Opportunity - if you’re a melee build - this will help your ranged buddies a lot. And if you’re a ranged build - this is an easy way to both deal extra damage and apply a spicy inhibitor out of turn.
Unbreakable Will - likely overkill, but there’s a lot of fear effects in the game, so being prepared against them can come in real clutch.
Terrifying Presence - only good if you took improved demoralize and have the Intimidation to make it work. The races that can pick this feat are (as of 2022-06-21) half-orcs and xenometric androids (half-orc).
Tight Fit - really depends on the campaign. Might be either completely useless, or pretty cool. If you are to do a lot of tight ruins or dense corridor exploration, grabbing this on a Large PC will pay off in the end. But if you play any published Adventure Path you can likely forget about it.
Toughness - it’s not a lot, but it will add up in the end. Important pick for melee Biohackers. The other bonuses are nice, too, especially if you’re in an effect of a smoke grenade.
Unfriendly Fire - hilarious and powerful ability for melee builds that makes you an unattractive target for your enemies, if you have the Charisma and Bluff for it to work. And as a Biohacker you can definitely specialize in it relatively well with minimal effort.
Unionist - you want to be hitting your targets to apply Biohacks to them.
Versatile Specialization - get full level to damage of non-opereative and non-small arm weapons that you are proficient in. Useless if you already learned arms expert theorem.
Note that you must be proficient with the entire weapon category in order to take this, meaning that if you want to, say, add your full level to damage of a longarm injection weapon - you’ll first have to learn the longarm proficiency feat and only then learn versatile specialization. It does use up two feats, but it lets you save a theorem by not picking up arms expert theorem.
Weapon Focus & Versatile Focus - the feats that enhance your attack bonus.
Weapon focus is pretty much mandatory if you use your weapon a lot, which will be almost every Biohacker. Since we’re a ¾ BAB class, starting from lv9 this feat will give us +2 to our attack rolls, instead of just +1. Try to grab it in your “main” weapon type so you can deliver the most mayhem for the smallest investment. It’s a must have for most builds in the game. Note that you must be proficient with the entire weapon category in order to take this, meaning that if you want to pick up weapon focus for a longarm injection weapon you use - you’ll first have to learn the longarm proficiency feat.
Versatile focus, on the other hand, is a quality of life feature. Other classes get to use more weapons, but Biohackers are largely limited to just injection weapons, making this feat very situational.
Wind Shield - an essential component of a potent lategame defensive flying build. Biohackers aren’t the most most full attack-dependent class in the game, so this could be almost akin to taking cover while in the air, which is a crazy buff for survivability for ranged builds (since they’re already immune to melee attacks, unless enemies also fly). Melee Biohackers won’t really be able to make use of this all that often, due to having to spend move actions on approaching enemies.
Note: this feat requires a move action to activate. However, keep in mind that you need to spend a move action to attempt the Hover Acrobatics action just to stay in the air without moving. If you have flight speed with perfect maneuverability, however, not only do you automatically succeed on the Acrobatics check to stay aloft, but you can attempt to Hover as a swift action. Getting perfect maneuverability is easy: get any average maneuverability flight source (whether through gear, race or advanced locomotive adaptation theorem) and combine it with the glider foil armor upgrade. 

Multiclassing & Archetypes
Multiclassing is a very potent way of adding depth to the character narratively and getting mechanical flexibility. Biohacker usually is one of the absolute best classes to multiclass into, thanks to a wide plethora of available abilities at level 1. However, multiclassing out of it can be a good option, too. 
When considering multiclassing or picking an archetype - you have to first think of what you’re trying to achieve, and then decide if the price is acceptable. As a rule of thumb it doesn’t make your character stronger per-se, just allows for more varied builds.

Multiclassing
Now the main issue with multiclassing is that it delays your entire main class’ progression. Multiclassing a Biohacker is fairly easy, as the class already has a very strong baseline at lv1, so multiclassing out to focus on different aspects of different classes should be rather easy. That being said, I am assuming that you still want to remain as a main class Biohacker, primarily. Because of that I’ll write specific breakdowns of 1-3 level multiclasses and give my general thoughts on getting 4 levels and more. Note that taking even a single level of another class locks you out of superserum, so if your game is going to reach level 20 (or starts at that level) - think long and hard if multiclassing is really worth it for you.
If you decide that you want to give it a spin, I suggest reading this reddit thread, addressing many common multiclassing questions, in addition to the multiclassing chapter in the CRB.
These options can really majorly modify how your character plays, so always think about flavor! Descriptions and fluff are very important in roleplaying games, and highlighting what makes you different from the others is fun and enjoyable. 

Envoy - great option for Biohackers who want to maximize their effectiveness as support for the party.
1 level: you’re probably looking for the get ‘em improvisation to get +1 to your (and your party’s attack rolls), quick quaff for easier application of serums that you haven’t loaded into your weapon, frustrating target if you’re using a melee build or look alive for better Initiative. You also get a stupid amount of skill ranks and class skills (many of which aren’t available to you by default). Expertise is pretty nice, just remember that it’s also an insight bonus, meaning it doesn’t stack with our scientific method.
Alternatively, you could drop expertise for combat expertise. It’s basically like the operative’s trick attack, but even better. The chosen skill should probably be Sense Motive for both types of Biohackers, or Culture for studious ones.
2 levels: grab that one improvisation you really want, but couldn’t take at lv1. Likely isn’t worth it.
3 levels: grabbing maneuver expertise to increase your odds of that sweaty disarm attempt if you picked up combat expertise. Miracle worker is one of the best features in the game, but you don’t get the level bonus to make this effective in the mid to late game. If you notice yourself attempting Medicine check a lot, inspired medic can be nice. Some nice social stuff here. 
4+ levels: aside from grabbing improved get ‘em there’s not much in this ¾ BAB class to warrant a beefier multiclass on its own, but it provides for a good combination for a support/skill-oriented Biohacker.


Mechanic - Mechanic lets you pick up some technological tools to compliment your biological trickery.
1 level: Exocortex gives you proficiency in heavy armor, longarms (which you can expedite into full level bonus to damage through versatile proficiency) and shields. The move action tracking is utterly useless). Experimental armor is pretty bad, as you can get most of the things this grants you elsewhere. Experimental weapon’s proficiency is nice, but the rest of the abilities are pretty useless. Don’t even bother with the drone.
Half of bypass is either meh or nifty. The class skills only give you Athletics and Piloting. And the custom rig is just quality of life. Overall: nothing special, but the proficiencies are nice.
2 levels: you get mechanic tricks. None of them are something you particularly need. Most of them are something you can replicate with gear, or something you can’t really capitalize on as a Biohacker.
3 levels: overload is cool, but your DC will be too low. Weapon spec in a weapon you really wanted helps you save a feat.
4+ levels: remote hack is either a good or fantastic feat (GM dependant). This lets you pick up some more technological tools, but overall won’t be of interest to most characters.


Mystic - great pick for instinctive Biohackers, allowing them to get more bang out of their high Wisdom score. Caster level is gonna suck, though. Bonus points for using your microlab as a spell cache and flavoring your spells as different kinds of magical injections.
1 level: proficiencies suck, the class skill list is mostly the same, but grants you Disguise and Mysticism. Healing touch is useless with your Mystic levels. Connections, however, are very interesting. Geneturge is an especially fun and flavorful option for the Biohacker. Empath and overlord are good for some social flexibility.
Finally, you get some Mystic spells. There’s a lot of decent social spells, such as charm person, command, confusion. Polymorph can grant you more flexibility in problem solving. They’re probably the most reliable options you can pick.
2 levels: mindlink is absolutely not worth it
3 levels: some of the 3rd level connection abilities are pretty dope.
4+ levels: overall it’s not a bad multiclass once you’ve picked up your core abilities. Higher level spells can give you more flexibility and options in and out of combat.

Nanocyte - Nanocyte has great abilities, but most of them scale with nanocyte levels, making this class very unappealing to multiclass into (or out of, for that matter). Plus, being a CON class hurts its potential for multiclassing somewhat, as your Constitution - while probably not very low - likely won’t be very high.
1 level: gives you “physical” skills like Acrobatics, Athletics & Stealth as class skills. Proficiency in longarms and advanced melee can help you save a feat if you plan to pick up weapon specialization early. Nanocytes don’t get heavy armor, making this multiclass much worse for melee Biohackers. You also get access to the nanite array, which are fairly powerful and flexible abilities that scale very nicely with nanocyte class levels. Issue is, it makes it suck for multiclassing. Your sheath array will essentially just be a +1 to Reflex saves (that doesn’t stack with the ring of resistance btw) and some skills, your cloud array is just a 10% miss chance that is likely to hurt an unprepared party as much as the enemies and won’t give you as much mobility due to your middling CON score, and your gear array will just be creating stuff you almost definitely can afford to just buy yourself. Eldritch nanites is not that amazing, either. That being said, the primary nanocyte faculty is a nice bonus to have early on. Of them, discorporation and redirection are the best.
2 levels: gets you defensive dispersal, which is kind of okay at low levels if you have a decent CON score, but becomes much less useful without scaling nanocyte levels. Knacks aren’t all that amazing for you, the most appealing options are probably heavy armor edge and instant ward. 
3 levels: you get a pretty good weapon specialization (with both longarms and advanced melee), as well as cyto-conversion, which is neat, but can mostly be achieved with gear. 
4+ levels: lets you further enhance the powers of your nanite array and get more knacks, but the latter suck, while the former don’t really improve the core Biohacker experience much at all. Nanocytes do have a lot of interesting medical support abilities, such as Thousand Stitches and the Regeneration Faculty. That being said, a mainclass Nanocyte with like 1 or 2 levels into Biohacker will get way more out of that multiclass than the other way around. 

Operative - the entire shtick is focused around full actions, no matter if you use trick attack or stunt and strike. Both combine extremely well with our biohacks and give us higher odds of hitting and applying them. Not to mention that the flat-footed condition helps our low BAB selves. The strong Reflex save bonus is nice, too.
1 level: there’s a lot to love here. A ridiculous number of skill ranks and a decently expanded list of class skills. Bonus to literally every skill and initiative is excellent. Specializations essentially give you two skill focus feats. Pick the specialization that you have a very high skill bonus to. Detective is likely going to be a reliable choice for all Biohackers. 
Replacing trick attack with stunt and strike is almost always a good idea, because trick attack’s tiny damage bonus will not be useful in the long run.
Dirty trick is good for free conditions (2nd printing of COM removed both Blinded and Entangled, but Sickened is still pretty awesome and Deafened can be situationally cool, too), feinting stunt is great if you don’t have any other Operatives in the party, knock down is perfect for melee Biohackers, set-up is great if you have a lot of spellcasters in the party. There are some other decent ones, but those ones are definitely highlights.
Can’t recommend using marked for death. It’s hard to use even for full Operatives, and our frail selves should definitely stay away. Especially with the nerf in 2nd printing of COM.
Overall a single level of Operative gives Biohackers a lot of utility both in and out of combat. Thanks to COM almost any class can benefit greatly from 1 level of Operative.
2 levels: evasion is actually really nice to have. You also get an operative exploit. There’s nothing that is instantly amazing for you, but armor optimizer, combat trick, trap spotter are decent.
3 levels: increased edge is nice, increased movement is nice, weapon spec is kinda useless, though. Quick cover can provide some neat defense for a ranged Biohacker. 
4+ levels: you get some more flexibility out of combat. But realistically, if you plan to take any more levels, you’d benefit more from multiclassing a full Operative into Biohacker, than the other way around.


Precog - your caster level is gonna suck, but studious Biohackers will have the ability score for this. Instinctive should consider all ratings one step worse.
 
1 level: your class skill list expands, notably with Acrobatics, Mysticism and Stealth. Free training in longarms or advanced melee helps save one feat for both melee and ranged Biohackers. 
The spell list isn’t half bad, and studious Biohackers may have the INT score needed for the debuffing spells, most notably dream of home, but confusion, lesser is nice, too. As for buffs, communal bond and swap initiative, as well as keen senses are actually pretty nice to have. You also get the paradox, which scales nicely with Dexterity and not actual Precog levels. And while yes, your application will be very limited, it will still be very useful in your day to day adventuring. There is no one best anchor to choose, but fragmented past is amazing for a skill monkey, while the gap can be useful to shore up an important save.
2 levels: you get a choice of a single temporal anomaly. Of them, safeguard and tactical timing are kinda okay, but not essential. Future training gives armor proficiency for melee Biohackers who care (annoying that shield proficiency isn’t on there).
3 levels: you get weapon specialization with your chosen weapon type (likely longarms or advanced melee), which is great, since this lets you add your full level to damage with longarms/advanced melee non-operative weapons. You also get chronomantic defense, which is a very powerful support ability that scales flawlessly with just your Dexterity (increasing the number of paradoxes you have), irrespective of your Precog level, which is awesome. Works better for DEX builds. You also expand the usage of your paradox.
4+ levels: you get more spells of higher levels and there’s a couple of spells that may interest you, such as mirror image for better personal defense, social reset for social campaigns and time loop for a long-lasting debuff even on a successful save. Temporal aggression can come in clutch for high damage weapons sometimes, but very rarely. The lv5 temporal anomalies can offer some fun features, such as I Knew You’d Say That for social campaigns, 


Solarian - the class is quite MAD (multiple ability dependent), but provides good bonuses for melee Biohackers. Rather mediocre for ranged ones.
1 level: Full BAB class, yay to attack rolls. You get some decent physical and social skills + any 2 as class skills, proficiency in shields (great at both passively and actively increasing your defense) and advanced melee (saves you on a feat if you want to get full level bonus to damage), two stellar revelations (black hole and supernova will have terrible damage and DCs when multiclassing) and a solar manifestation. 
Talking about manifestations, the only viable option is solar armor, as you just get a freebie +1 to KAC and EAC (glowing armor is hella ballin’, too). Note that it’s an enhancement bonus, same as your basic booster, meaning they do not stack. The solar flare and solar weapon are awful since they’re not injection weapons. Solar shield is kind of pointless, as you can simply buy your own shield.
2 levels: you can finally get some 2nd level stellar revelations, but most of them really aren’t all that good for you, as, according to multiclassing rule, “almost all class features are based on the character’s level in the class that grants that feature”. That means that you’ll count as a level 2 Solarian for all of those cool features like plasma sheath. A lot of abilities require standard actions, too, which sucks, because you want to apply your biohacks through weapon attacks. Stellar rush is mad good for melee builds, even with the sucky additional damage as the only other way to get a standard action charge is to play a level 5 Soldier with the Blitz Fighting Style.
3 levels: melee Biohackers will be glad to get weapon specialization in advanced melee, which is nice if you want that full level bonus to damage early. Sidereal influence is a cool insight boost for more utility. That combined with the great BAB makes this a decent option for melee Biohackers.
4+ levels: might be a somewhat attractive option for melee Biohackers, as it gives them a bit more options and further enhances their AC with solar armor. That being said, you’d be losing out on your high level theorems, which may be a sacrifice you’re willing to make, as Biohacker is very front-heavy.


Soldier - one of the best multiclasses in the game for most classes (thanks to the incredibly versatile Soldier chassis), and it serves the Biohackers just as well. If you want to break skulls good - this is where you’re going to look. Great BAB progression and saves, awesome health, and powerful class abilities. What’s not to like?
1 level: a single level gives you solid physical skills, Intimidation and Piloting as class skills. More importantly you get proficiency in all weapon types and heavy armor (the latter being especially good for melee Biohackers)! That alone helps a melee build save on a bunch of feats. And as if that wasn’t enough, you also get an entire primary fighting style. There are some really good ones. Ambusher and blitz (the latter being especially great for melee builds) help you go first, guard helps us survive a bit longer, silent slayer and squad are decent for a stealth melee build and groups with a lot of ranged party members respectively. Wrathful warrior is an easy way to get some extra damage in melee. Sharpshoot is good for ranged builds that may have issues shooting into melee.
Grabbing 1 level of Soldier is an excellent way for ranged Biohackers to get proficiency in longarms (making grabbing versatile specialization easier).
Melee Biohackers will really appreciate the fighting style benefits and access to both advanced melee weapons AND heavy armor, potentially multiple feats with a single level multiclass.
2 levels: this gives you a combat feat. A nice benefit, but mostly for low level games, as the Biohacker doesn’t have that many “mandatory” feats.
3 levels: grants you the best version of weapon specialization (then again, you can just take versatile specialization after your 1st multiclass level) in the game and a coveted gear boost (which you can replace for a feat boost). Some options are extremely powerful, but they are definitely far better for melee builds than ranged ones.
There are a lot of awesome gear boosts, my favorite being the armored advantage, deflecting smash, melee striker and unburdened shield.
Feat boosts are incredibly powerful for melee builds. Beatdown (though only if combined with 1 level of Operative’s knock down stunt), defensive cleave and spinning cleave (this one can increase your damage output dramatically, but watch your AC and hit points).
Ranged builds instead will probably be most interested in springing shot and multi-weapon strike.
4+ levels: an extremely powerful combination for melee Biohackers that can provide many benefits to both defense and offence. Ranged builds don’t get much aside from the good BAB and HP, but it is the only full BAB multiclass that actually provides at least some benefits to ranged builds. Focus fire is excellent, too.


Technomancer - a Biohacker becomes the ultimate Nanoalchemist. Can be an interesting option for a studious Biohacker. Bonus points for using your microlab as a spell cache and flavoring your spells as different kinds of magical injections.
1 level: Mysticism and Piloting as class skills. The proficiencies stink, as does the HP. The granted spells can definitely be of great use. Definitely worse than the Mystic’s 1 level dip, since you do not get any additional features like the Mystic’s connections provide. That being said, the added spell slot with the spell cache are great. 
The spell list is vast and ever-useful. Magic missile can help you stack up some confirmed kills on dying targets, incompetence to trivialize encounters, grease to mess up your opponents, akashic tutor to be great as skills, patch tech to solve tech challenges and keen senses to help improve your Perception are some nice options.
2 levels: the vast majority of magic hacks affect spells, which is amazing for spellcasters and pretty useless for martials. That being said, grabbing empowered weapon to guarantee hits with your weapons and add some extra damage is an excellent pick.
3 levels: spell focus is pleasant to get for free, techlore is probably too anemic to count and the specialization is useless. Overall not worth it, unless you plan to take more than just three levels.
4+ levels: magic can get you more options in and out of combat to support your party in a more magical sense and your DCs are likely not going to be lower than most full Technomancers. Might be a fun pick.


Vanguard - there’s absolutely nothing for ranged builds here, but even melee builds don’t really get much beyond the HP, BAB and proficiencies. Vanguard is an excellent class, but awful multiclass. Pick a Soldier, instead.
1 level: You get proficiency in all armors, shields and advanced melee weapons which is very nice. The entropic pool, which increases the damage of entropic strike (which only scaled with vanguard level) or gives you a tiny speed boost is useless. Entropic strike also doesn't come with a built-in injection, so you’ll still need to be buying weapons anyway. The vanguard aspects do provide a bonus to combat maneuvers.
2 levels: grants you mitigate (which only scales with Vanguard levels, hence useless) and a vanguard discipline. Dampen can be useful when fighting enemies with AoE attacks (dragons, mages etc.), evasion is cool. The rest are kinda blegh.
3 levels: reactive is okay, but works only once per day. The weapon spec is okay for melee Biohackers, but you can already get it through a feat.
4+ levels: there’s not much to look forward to, really. None of the bonuses that the class provides are that good if you’re not a full Vanguard. The defensive abilities are pretty eh for you.


Witchwarper - the Witchwarper is in a weird place. Both Technomancer and Mystic get unique abilities that enhance their spellcasting chassis in some major ways (spell cache and its alternatives for Technomancer and connections for Mystic). The Witchwarper gets infinite worlds, which is… basically extra (bad) spells known, since you have to spend spell slots on those abilities. It sucks. Which is weird, because the playtest version of the ability was just something they could do a few times per day, which was fun and flavorful. No idea why Paizo nerfed it, since the feature wasn’t even broken back in the playtest. But overall this makes it a pretty eh multiclass, especially for Biohackers, as the studious ones would prefer a Technomancer multiclass, while instinctive ones would prefer to become Mystics.
1 level: decent class skills, some of which you don’t have. Strong Reflex save is welcome. Infinite worlds is trashy.
Spell-wise, churn fluid and grave words are fun, charming veneer can help our social stuff, detect thoughts is good for skullduggery. Don’t forget that you can get all of this stuff with the reality glimmer feat and that it uses your Charisma for save DCs.
2 levels: gets you a paradigm shift. A lot of the good ones require a very high Charisma score and Witchwarper levels, so you can pretty much ignore anything that requires a save. Worse yet, the durations are equal to your Witchwarper level, making even the best stuff here pretty bad use of actions. Disrupt creature is pretty good (shame it uses a standard action) as it has no save, but uses your very limited Witchwarper spell slots. Thwart ability is a very nice use of Resolve Points and reactions for a ranged Biohacker and lowkey the only real reason you may want to take such a multiclass..
3 levels: weapon specialization is the exact same as yours, while compound sight is just too tiny of a bonus to only a single skill.
4+ levels: Witchwarpers have a fairly good spell list that combines the versatility of Technomancer and Mystic. That being said, class features are kind of a letdown, so this probably isn’t the strongest of choices. However, Biohackers who already feel like they’ve picked up everything they need from their class and have a high Charisma score can definitely make use of them.

Archetypes
Archetypes are surprisingly overbearing. They aggressively replace a ton of class features. There’s a common sentiment in the Starfinder community that it might be best to pick an Archetype that interests you first and then look for what class can fit it. 
TheHiddenTruth.info has a convenient button in the top right of every archetype option to show what you’ll be replacing if you pick that archetype.

So, the rules. For any level at which an archetype provides an alternate class feature, you sacrifice the following:

Multilevel 2nd, 4th, 6th, 12th, and 18th Levels: You don’t gain a theorem. A significant price to pay.


9th Level: You don’t gain the use of a second spark of ingenuity per day. When you reach 15th level, you can use only two sparks of ingenuity per day. Probably something you can sacrifice if the feature is worthwhile.

So, as you can see, if you pick an archetype with particularly many replaced abilities - you basically lose the majority of your theorems, which is a dramatic sacrifice for any Biohacker, but not exactly crippling, as our Biohacks are our true strength.


Breakdown (replaced levels in parentheses):

Android Abolitionist (4, 9, 18) - not charmed. The bonuses are maybe nifty for a very specific type of campaign, but the benefits are not worth the cost.

Cost: two theorems, one use of spark of ingenuity per day.
Benefit: Bluff and Diplomacy as class skills, some abilities to lay low, and a bit of damage reduction to an adjacent creature once every minute.
Arcanamirium Sage (2, 6, 9, 12, 18) - replaces nearly the whole damn package. The archetype is incredibly flavorful. You can only cast a spell from a gem once per day, which sucks. That being said, if you focused a lot on Mysticism and want to be using a lot of magical worn items - this can be a fun option.

Cost: four theorems, one use of spark of ingenuity per day.
Benefit: makes it easier to identify and buy magic items, lets you use spell gems as spells known once per day, lets you attune to up to two extra hybrid or magic item, recharge a magic item once per day, 
Aspis Mastermind (4, 6, 9, 12) - very charisma-heavy archetype with some pretty great intimidation and Bluff bonuses that’ll benefit you a lot in a social campaign. Gives you Intimidation as a class skill, which is important for any demoralize-focused build. The lv6 feature is great on paper, until you get to the fact that it uses your standard action. The higher level features are a little disappointing.

Cost: three theorems, one use of spark of ingenuity per day.
Benefit: intimidation bonuses and some battlefield action support for your party.
Assassin (6, 12, 18) - Can be fun for a sneaky build. Killing someone with a sniper rifle that doesn’t normally deal damage is awesome flavor. Some Biohackers can weather cost.

Cost: three theorems.
Benefit: gives you a chance to become stealthy even when observed by many creatures, a chance to instagib an enemy.
Augmented (2, 4, 6, 9) - requires a big investment of theorems, and early on. This very likely isn’t at all worth it in the early game, but if you’re making your character at a higher level (say for a level 7+ Adventure Path) this can actually be an extremely powerful upgrade. Basically the higher level you are - the more worthwhile this is. This can give you extremely powerful benefits for a fraction of the price.  

Cost: three theorems, one use of spark of ingenuity per day.
Benefit: cheaper body augmentations, can install extra augmentations, use your body as a battery, cheaper stabilizations, ability to squeeze some extra utility out of personal upgrades.
Battle Leader (2, 12. Optionally 4, 6, 9, 18) - one of the best archetypes in the game. Gives ranged Biohackers a very nice use of their generally unused reactions, but melee builds benefit from it, too. These are abilities that you’ll be able to use literally every fight, which is awesome. The fact that the price is cheap as hell is a huge benefit, too.
As for which ones to pick, got ’em is great if you have the Charisma for it, regroup is great even with minimal Charisma, and tread carefully! can help get people out of enemy reach.

Cost: two theorems, optionally the full package.
Benefit: awesome reaction-based party buffs.
Battleflower (All optional 2, 6, 9, 12, 18) - this archetype was nerfed quite significantly with the most recent errata. The fact that staggering strike only works with your unarmed attack (can’t inject with that) sucks. The ability to tumble around the battlefield is cool. Using Acrobatics instead of Diplomacy is good, because our DEX is likely going to be higher than CHA. Going first is likely not as great for you as some other characters, unless you picked something like hampering inhibitor.
With the errata to COM, stunning strike has been replaced with staggering strike. A decidedly less impressive debuff, but still a useful one. And the paralyzation is replaced with a stun at lv20. Significant debuff to this archetype, though it’s still okay for some builds.

Cost: as much as you’re ready to give up.
Benefit: good weapon proficiencies, use Dexterity instead of Charisma in some social situations, the capability to stagger enemies when you attack, safer combat mobility, potentially always going first in combat.
Commando (4, 6, 12. Optionally 9, 18) - the higher Stamina is greatly welcome for a melee Biohacker, but most of the bonuses are very niche.

Cost: three theorems, optionally an additional theorem and one use of spark of ingenuity per day.
Benefit: a bit higher Stamina pool, bonuses against specific save types.
Cycle Scholar (6, 12, 18) - we’re not solarians and can’t get revelations. The party buffs it has do not make it worth the investment.

Cost: three theorems.
Benefit: fairly weak battlefield support for your party.
Deep Cultures Specialist (9, 12, 18) - this is an AP archetype, and it really shows. The abilities are very niche, but fire resistance 20 is kinda hype.

Cost: two theorems, one use of spark of ingenuity per day.
Benefit: fire resistance 20, niche retrocognition spell usage and the ability to provide the flaming fusion to the entire party.
Divine Champion (2, 4, 6, 12, 18) - radical change of your class kit. Kind of blegh in the early game and uses up a whopping five theorems, but man, getting lv6 Mystic spells that use your key ability score for spellcasting is insanely awesome and will doubtlessly make the party’s mystic feel cheated by level 18. The “quality” of this archetype depends on the deity you’ve chosen (and more specifically the connection): devastator, healer, melophile, mindbreaker, overlord, shadow and shaper are the best ones, but some of the others are pretty good, too. An excellent archetype for Devastation Ark or a similar high level game, as this archetype definitely shines the brightest with its later features.

Cost: five theorems.
Benefit: the effect of a low level fusion, ring of resistance, lv1-6 mystic spells (that use your own key ability score, not Wisdom!). 
Doshko Specialist (2, 6, 12, 18) - borderline broken archetype that provides bonuses that the traditional (unwieldy) doshko can’t really utilize in any reasonable way. Your attack bonuses aren’t good enough for a dedicated maneuver build (you already have inhibitors, don’t you?). The lv18 feature is pretty neat, but comes way too late.

Cost: four theorems.
Benefit: more combat utility out of non-unwieldy doshkos. Which sacrifices your damage output.
Entropic One (2, 4, 6, 9, 12, 18) - gives you some cool magical abilities, but has too many bad features. 
Entropic thoughts is meh, as telepathy has pretty limited usage. Entropic shield is kinda gimmicky, as the cheapest shield that doesn’t impact your max DEX bonus to AC is already good-enough, but can still be useful to a build that wants to maximize AC. Entropic grasp is pretty powerful, but it requires you to pick up a lot of third eye feats to get more uses, which aren’t that amazing. Entropic flight is pretty weak by that level. It’s fast, but you can just get a forcepack at that same level, which is just better. Discernment is the real cream of this archetype and provides a whopping +2 to your attack rolls against a creature, which is absolutely huge, considering how tight Starfinder’s math normally is, but you’ll have a hard time reliably making that DC, since it’s very high for a class that won’t be specializing in Wisdom. Entropic travel is kind of a gimmick, since you probably don’t want to leave your starship behind (and you probably have one). 

Cost: five theorems, one use of spark of ingenuity per day.
Benefit: some magic-like abilities, telepathy, a free scaling tactical shield and a way to use Mysticism to give yourself a big bonus to attack rolls against a specific enemy.
Esotericist (All optional at lv 2, 6, 9, 18) - we’re not mages. If you multiclassed into one, then the benefits the Esotericist provides are likely overkill.

Cost: only what you’re ready to give up
Benefit: nothing, because we’re not mages.
Espionage Specialist (4, 9, 12) - a bit niche, but could be okay for a covert/social campaign, as “advantage” on as many skullduggery checks as you need per day is excellent.

Cost: two theorems, one use of spark of ingenuity per day.
Benefit: more reliable covert actions, easier deceptions and a tiny damage buff.
Fixer (6, 9, 12, 18) - do you really need an archetype for cleaning? It has excellent fluff, but you can likely get features this archetype gives you through theme features and general roleplaying.

Cost: three theorems, one use of spark of ingenuity per day.
Benefit: easier to talk with criminals and conduct criminal activity on a large scale.
Free Trader (2) - I’m not an oracle, but something tells me this will be an excellent choice for the Fly Free or Die Adventure Path. Works great for any open world/sandbox-y Starfinder game. Even in conventional games this archetype will probably help save you tons of cash.

Cost: one theorem.
Benefit: a bunch of abilities that help you be a better trader.
Instinctive Metaphysicist (9, 12, 18) - the ability to cast high level illusion spells is very nice. The mindscape challenge is a wicked cool ability, and flawless for stealthy assassinations, but not too clear. Like what “traits” can you set? That it’s all lava? That the enemy’s side is pelted with meteorites? It’s either stupidly good, or just a neat little debuff to make the enemy burn actions. It could also be pretty dangerous, if you drag a high CR creature in there and it just ravages you with full attacks. Talk to your GM.

Cost: two theorems, one use of spark of ingenuity per day.
Benefit: rest quicker, cast high level illusion spells, create a mental dueling arena.
Instructor (9, 12, 18) - reducing the DC by 5 is crazy good, assuming some skill is used often, but the aiding bonus is a bit pointless when others will probably be the ones aiding you. By level 18 you pretty much turn one skill to automatic success, no matter what task it is. A powerful fantasy, but is it worth the cost? Depends on your game.

Cost: two theorems, one use of spark of ingenuity per day.
Benefit: extreme improvements to one class skill.
Junkomancer (2, 4, 18) - we’re not mages and nothing here is interesting for us.


Cost: three theorems.
Benefit: More convenient casting of junk spells.
Kalistocrat (all optional 2, 4, 6) - fairly powerful archetype for social campaigns. Of the lv2 features, cultural studies definitely stands out with its power in social encounters, especially for studious biohackers who may have a very high bonus to Culture. Lv4 feature is great in a campaign where you would be moving a lot. The lv6 features can probably just be skipped.

Cost: only what you’re ready to give up.
Benefit: Use culture to change attitudes, powerful social abilities, Some abilities to lay low, and a bit of damage reduction to an adjacent creature once every minute.
Magic Academy Student (2, 4, 6) - we’re not mages.


Cost: three theorems.
Benefit: nothing.
Mediator (2, 4, 9, 12) - not bad, but your Charisma likely isn’t too stellar. If you do play as a very charismatic character, this is actually a pretty nifty choice. Works even better with a GM who’s open to peaceful solutions. That being said, the cost is very high, and the benefit, while nice, isn’t a must-have.

Cost: three theorems, one use of spark of ingenuity per day.
Benefit: powerful social abilities, strong capstone providing good bonuses to Will saving throws and flexible initiative.
Medic (studious | instinctive) (2, 9, 18) - so here’s the thing, it’s either kinda bad, or a real gamechanger, all depending on your scientific method. Instinctive as-written doesn’t allow you to apply WIS to Treat Deadly Wounds, as  it specifically adds INT to the amount healed, so it’s not as good. If you are studious and picked up the field dressing theorem to restore hit points, the Medic archetype’s doctor feature allows you to restore surplus HP healing to SP. Granted, you do not restore as much as a mage could with their powerful healing magic, but it’s still nice to have. The lv9 feature really soups up the Treat Deadly Wounds feature, allowing you to restore a good amount of health to your party members in combination with sprayflesh, a medical laboratory (through your handy custom microlab) and first aid expert.
While this isn’t as dramatically broken as this archetype’s combination with the healer connection for Mystics (which basically turns your party immortal), it can still be well worth the cost.

Cost: two theorems, one use of spark of ingenuity per day.
Benefit: abilities that have incredible synergy with healing abilities.
Phrenic Adept (2, 4, 6, 9, 12, 18) - radical change to your character, requiring a huge investment, but you get a good list of faux-mage abilities. If none of the theorems grab you too much, this can actually be a pretty fun build. Provides a good bonus to saves against a good list of debilitating spells. Gives you a wider list of “spells” than the Divine Champion, but later. Pretty good choice for social games.

Cost: five theorems, one use of spark of ingenuity per day.
Benefit: telepathy, mental defense, several spells and mental abilities.
Powered Armor Jockey (6, 9, 12, 18) - so, right away, full level Biohackers can’t really take this, because we get +5 BAB after level 6, meaning we won’t be able to take the Archetype in time. You can only take this archetype if you multiclass into another class first, so you delay your Biohacker levels. Secondly, ranged builds can skip this. For melee, however, this is pretty mediocre in lv1-13 games, but extremely attractive in the end game. Getting powered armor may be tricky, as you’d need to grab both heavy armor proficiency and powered armor proficiency through feats (or a multiclass into one of the heavy armor classes for 1 level + the powered armor proficiency feat). However, it may be a very attractive option to melee Biohackers, as you can just leave Strength at 13, have high Dexterity, then jump into the powered armor to have both an extremely high Dexterity and Strength.
The lv6 and 9 features are nice, but probably aren’t worth on their own. However, if you play Devastation Ark or a similar high level game, the level 12 feature can grant you what is essentially a +6 Strength over what the armor already grants you. That means you can eventually end up with an absolutely mind-boggling 36 strength (an insane +13 Strength modifier!), which easily makes up for the so-so BAB we may have. Don’t forget you add that to damage, too. Finally, just to seal this already insane late game deal - the ride-or-die rig feature makes you an insanely tough nut to crack, as crafted powered armor counts as 2 levels higher for hit points and hardness, and it already has crazy hardness by default, meaning the damage it takes will be severely reduced. Biohackers get a good amount of skills, so you can probably grab Engineering if nobody else has it. Might need to stock up on nanite patches.

Cost: three theorems, one use of spark of ingenuity per day.
Benefit: situational early game abilities, but extremely potent late game boost to melee builds’ damage output.
Safety Inspector (2, 6, 12) - Biohackers are really good at Perception, so we can make use of this ability quite well. The archetype offers pretty solid anti-trap options. I’d only recommend it in a dedicated megadungeon campaign, as losing 3 whole abilities over just traps is a bit overkill. Keep in mind that in Starfinder you count as your own ally, unless an ability says otherwise.

Cost: three theorems.
Benefit: great anti-trap options.
School Specialist (2, 4, 9, 12) - you’re not a mage.

Cost: three theorems, one use of spark of ingenuity per day.
Benefit: up to two extra spell slots, up to four extra spells known and two unique abilities.
Skyfire Centurion (4, 6, 9, 12) - excellent archetype if you want to play the dedicated support character. Very flavorful, interesting, and something you can probably flavor to work through your microlab. Note that lend expertise isn’t limited to a few uses per day - you can literally give someone one of your feats every single fight. Starting at lv4 means you can pick up a lv2 theorem, which is very nice, too. Consider this: between your basic inhibitor providing a -2 AC, harrying fire providing +4 to someone’s attack - that’s an absolutely crazy bonus that basically increases your buddy’s odds of hitting a target by 30%! If your buddy is a melee character and is also flanking a target, that’s a 40%  bonus! With battlemind link up you even get to apply that bonus while dealing normal damage with your attacks. Absolutely not to be overlooked!
But wait, there’s more! The concentrated fire feature allows you to absolutely slap enemies with higher rolls. If you or your buddy scored a nat20 - that’s TWO crits on the enemy! That’s absolutely brutal and even allows you to get away with a lower STR/DEX score, to a degree. If you and your buddies want to minmax - this definitely works best if the other person uses an unwieldy weapon, since you can’t full attack as a readied action. Finally, concentrated fire also allows you to do the same trick in space combat, too, which is a huge benefit to that.
Important note: the concentrated fire feature only works when you set the same condition for the readied action! I guess the balance act Paizo wanted to pull off here is that you’d only be able to use it with conditions like “The enemy enters through that doorway”, but you can be pretty petty with this, setting triggers like “When the enemy does anything that isn’t giving up”, which essentially allows you to perform it every turn. 

Cost: three theorems, one use of spark of ingenuity per day.
Benefit: better bonuses to covering and harrying fire, sharing combat feats, using higher of the two attack rolls, easier stabilizing of one ally in combat.
Spell Sergeant (2, 4, 6, 9, 12) - you’re not a mage.

Cost: four theorems, one use of spark of ingenuity per day.
Benefit: none.
Star Knight (2, 4, 6, 12) - pretty big archetype. Once again, only interesting to melee builds. Armor mastery is cool and useful (try to get the heavy armor proficiency before then, as 20% chance to ignore crits is great). Challenge is pretty good if you have the HP and defences to tank for the party, though you don’t get that many abilities that would make that build particularly good. Guarded attack sucks and should almost definitely be replaced, if you’re able to. Pike mastery is a big highlight of lv6, as getting Reach is noice. The lv12 features are all pretty mediocre for us. Overall, requires too much for what it grants, but the fortification % is ‘ery noice.

Cost: four theorems.
Benefit: heavy armor benefits and order-specific bonuses.
Starfinder Data Jockey (2, 6, 9, 18) - requires wayyy too much for the benefits that it gives. Look elsewhere.

Cost: three theorems, one use of spark of ingenuity per day.
Benefit: more flexible hacking and some minor tactical benefits.
Starfinder Forerunner (2, 4, 6) -  most of the good bonuses can only be used once per day. Nothing terribly special.

Cost: three theorems.
Benefit: two class skills, some survival and decyphering abilities, as well as a weak repair/heal function.
Starwright (6, optionally 12 and 18) - only has a single feature, the ability to weave starmetals into gear or vehicles. The real draw here are the armor upgrades: the one that provides spell resistance, specifically. Thing is, Spell Resistance doesn’t discriminate between harmful and beneficial spells. You can lower spell resistance as a standard action until the beginning of your next turn, but it still takes actions. 
Note: with COM’s errata the inubrix armor upgrade added that you can walk through solid objects “(though not doors and walls)”. So like… I guess you can walk through the space of a motorcycle…? An understandable nerf, but one that turns this nearly perfect pick to just a great pick. The new phasing through solid objects functionality is now also a bit more puzzling.
Overall, considering that this archetype’s price is basically a single theorem - it can definitely be worth it as it’s a very versatile option that gives you a whole lot of benefits.

Cost: one to three theorems.
Benefit: enhance technology with starmetals to gain unique abilities for 24 hours.
Steward Officer (2, 4, 9) - the bonuses are dubious. Like the combat feats are nice, but getting specialization three levels late will suck a lot (but it is irrelevant if you start the game at lv6 or above). Demand surrender is very fun and narratively interesting, though.

Cost: two theorems, one use of spark of ingenuity per day.
Benefit: some social skills, combat feats and a bonus for readying attacks and demoralizing enemies, while also allowing to demoralize with Diplomacy.
Stewards Infiltrator (2, 4, 6, 12) - definitely works much better if you have higher Charisma, but it’s a pretty neat thing for a more niche social game, especially if the GM allows you to change the “Steward” part to something more fitting the campaign. But as is, you can pretty much do most of what this allows you to do. The price is just too high
.
Cost: four theorems.
Benefit: pretty solid social interaction abilities, lots of good class skills and a lot of disguise abilities.
Stewards Stalwart (2, 4, 6, 12) - very similar to steward officer, except gives you more defensive abilities. Stalwart tenacity is bound to be useful, but you can only use it once per day, which sucks. Stalwart grit is a pretty excellent way to basically ignore around one hit per fight. Same as all other Steward archetypes, requires a bit too much for what it gives.

Cost: four theorems
Benefit: same as the Steward Officer, but has abilities that are more useful in direct, conventional combat.
Union Organizer (2, 4, 6, 12, 18) - teamwork benefits can be very powerful and ranged Biohackers don’t need their move actions all that much. Group negotiations just sounds like it should be a part of normal roleplay, so will be useless most times, unless your GM is somehow exceptionally rules-strict to the detriment of normal logic. The capstone is pretty amazing, though. It does require a very big investment, unfortunately, which holds it back, as you may as well just get the best teamwork feats with the party without anyone taking this archetype.
The current teamwork feats are Timely Coordination, Above and Below, Back to Back, Last-chance Grab, Stand Strong, Tandem Feint, Tandem Maneuver, Target of Opportunity, Unbreakable Will.

Cost: five theorems.
Benefit: teamwork support for the party.




Sample Builds
In order to highlight some possible, reliable builds for Biohackers, I’ll write down some example build progressions from lv1 to lv20. Not saying they’re the most optimized options, but this should give you an idea of pretty good stuff you could aim for, or modify to your needs. I’ll also provide some story blurbs to give you an idea of how you can reflavor Biohacker abilities.
I definitely suggest you make your own character from scratch! Nothing will feel as good. However, I know that a lot of (especially new) players get intimidated by the wealth of choices, so, please, see these builds as more of an inspiration, than a “Hey you! Play this!”



First Responder
A versatile studious Biohacker that focuses both on mobile support and ranged combat.
Name: Zeya Kataro
Race: Human
Theme: Battle Medic
Class: Biohacker 1-20.
Initial Ability Scores
Value
Strength
10
Dexterity
14
Constitution
10
Intelligence
16
Wisdom
12
Charisma
10


Backstory: Zeya is the oldest daughter in a very large family of law enforcement officers on Verces. Growing up surrounded by courageous older brothers and overly enthusiastic younger siblings made her feel like the only level-headed person in the family. Injuries were common and ranged from bruising after rigid training sessions to life-threatening wounds. And while everyone was away doing whatever, Zeya had also been the one to stay home and take care of her ill grandparents. When it came time for her to choose her life path, she decided to go for what she already knew best - healing people. Enrolling into the Cuvacaran University of Life Sciences, she has picked up several important skills and knowledge that allowed her to create her microlab - a hand-mounted machine filled with various nanite-infused liquids, capable of mixing to create biohacks. After graduating as a licensed doctor, she has received a residenture in a first response unit called “New-U Emergencies”, allied with the Stewards. Often coming along with Stewards to respond to crises, she has found a real niche for herself - getting right into danger to help those affected by terrorist attacks, natural disasters or anthropogenic hazards. It was honest, gratifying work. One that she was proud of. One that she was extremely good at. Her success and experience quickly made her be assigned to progressively more advanced situations. Eventually, she was officially invited to be a part of “Alpha Team One” - an elite unit of Overwatch branch of the Stewards, that travels through the different planets of the Pact Worlds, helping solve dangerous incidents.

Skills: Zeya is a professional doctor and a first responder, meaning her skills reflect her knowledge and need to survive in dangerous. She focuses on Medicine, Life Science, Physical Science, Perception and Acrobatics. Her hobby is drawing and she loves browsing the various kinds of art people upload online, as well, which is why she’s also interested in Culture, Computers and Profession (Artist). Later on she also gets some Diplomacy training.

Gear: The First Responder will be using light armor all the time. Whenever available she’ll be buying personal upgrades (increasing her DEX > INT > WIS). She’ll also try to maximize her mobility with a jetpack and other methods of movement. She will not be overly enthusiastic in purchasing the best firearms early on as she does not plan to be the heavy-hitter of her group, but will eventually upgrade her gun after she gains arms expert. Early on she’ll be using an injection longarm if she wants to be a bit more aggressive or an injection small arm if she needs a free hand for other tasks.

Level 1: Zeya’s custom microlab is a hand-mounted nanite lab-reactor that applies injections either through a retractable needle inside of it, or through small tubes connecting it to her weapon. She can use it to create biohacks. Injection expert allows her to use injection weapons with ease. Her primary field of study is anesthesiology (her master’s degree paper was called "Medical Innovations: Practical Applications of Nano-Anesthetics in Field Scenarios"). Her scientific method is studious. Finally, she also takes the auto-injector alt alternate class feature, which look like vials with carefully taped on tiny antennae. She always makes sure that half of her biohacks go to help the party’s frontliners (usually with +1 AC basic boosters)..
She also learns the mobility and lung puncture feats.
Level 2: Picks up the field dressing theorem in order to do her job better. Injection expert gets upgraded to make her more accurate with her attacks.
Level 3: Zeya’s skills grow as she gets weapon specialization and spark of ingenuity. She also learns the medical expert feat.
Level 4: New theorem, she learns medication mastery, granting her the use of analgesic, antitoxin, sedative, antiemetic and coagulant medicinals. Her field dressing improves.
Level 5: She increases her ability scores (DEX +2 to 16, INT +2 to 18; WIS +2 to 14; CHA +2 to 12). Her custom microlab’s power grows as it now functions as an advanced medkit. She also learns the breakthrough of her primary field of study. Finally she picks up weapon focus feat in the weapon that she uses.
Level 6: Zeya learns the cushion the blow theorem.
Level 7: Gains a secondary field of study (thaumapathy if there’s a mage in the party, or neurochemistry if there are none), as well as learns the shot on the run feat.
Level 8: Zeya learns the arms expert theorem. Her field dressing improves.
Level 9: Zeya’s custom microlab gets upgraded to a medical lab and can scan at a longer distance. Her injection expert feature gets upgraded further and she gains an extra use of the spark of ingenuity feature per day. Finally, she learns the parting shot feat. 
Level 10: She increases her ability scores (DEX +2 to 18, CON +2 to 12; INT +1 to 19; CHA +2 to 14). Additionally, she learns the elongation mutation theorem.
Level 11: Learns the secondary field of study breakthrough and picks up the improved initiative feat.
Level 12: Zeya gains the treat condition theorem.
Level 13: Learns her tertiary field of study (whichever one she didn’t learn at level 7) and picks up the dive for cover feat.
Level 14: Learns the greater field dressing theorem. 
Level 15: She increases her ability scores (DEX +1 to 19; INT +1 to 20; WIS +2 to 16; CHA +2 to 16). She also gets the skill synergy (Diplomacy & Acrobatics) feat.
Level 16: Zeya learns the improved treat condition theorem.
Level 17: The range of her custom microlab improves yet again, she unlocks the breakthrough of her tertiary field of study and she picks up the blind-fight feat.
Level 18: Zeya learns the greater treat condition theorem. Her greater field dressing improves. Finally her injection expert feature improves.
Level 19: Learns great fortitude as her final feat and she gains resolve analysis, giving her some extra resolve points when she needs them.
Level 20: Zeya finally unlocks the secrets of the superserum and learns the tranq dart theorem.

















Cerebral Iconoclast
A violent and destructive instinctive Biohacker with a focus on both debuffing and slaying enemies.
Name: Koth Nloqi
Race: Kalo
Theme: Mercenary
Class: Biohacker (Powered Armor Jockey) 16 / Soldier 4.
Initial Ability Scores
Value
Strength
11
Dexterity
16
Constitution
12
Intelligence
10
Wisdom
14
Charisma
10


Backstory: In a society driven by artists and scholars, Koth was neither. A delinquent and sadist, he was disowned and expelled from his home, thrusting him into a life of crime. Running as a thief and mercenary, his street-smarts eventually drew the attention of the Aspis Consortium, which took Koth in as a hired gun. He loved his newfound work, and the opportunities and funds it provided have become a great motivator. After taking initiative and taking the lead to save a mission his superior failed, he has earned great favor from the Consortium’s superiors. As a reward, an expensive surgical procedure was performed to augment his hormonal glands and nervous system, allowing him to secrete powerful matter-altering toxins and enhance his subconscious understanding of his surroundings, thus turning his nervous system into his microlab. Now Koth acts as a terrifying lieutenant of a Strike Team for the Aspis Consortium, flying around the universe and making sure the Consortium’s schemes can progress unobstructed.

Skills: Koth is a criminal and a juggernaut with an augmented nervous system. He’ll be focusing on Athletics, Sense Motive, Life Science, Physical Science and Survival. Through his instinctive scientific method he also always upgrades Intimidation and Perception.

Gear: The Cerebral Iconoclast will be using powered armor as soon as he can get it, using either light or heavy armor before that (depending on which one is available, but heavy will likely be better early on). Personal upgrades won’t be the utmost priority, but he’ll still try to get them (increasing his DEX > WIS > CHA). Weapon-wise, he shall be using ranged longarms or operative melee weapons early on, but will also eventually focus on injection melee weapons as soon as he gets powered armor, since they deal more damage. He will still be using ranged injection weapons after that, so he can apply biohacks at range. He’ll also try to buy a haste circuit as soon as possible.



Level 1 (Biohacker): Koth’s custom microlab are his augmented glands and nervous system that secrete toxins into the liquid surrounding him, which then feeds into his weapons. Injection expert allows him to use injection weapons. His primary field of study is anesthesiology. His scientific method is instinctive. He learns the lung puncture feat.
Level 2 (Biohacker): Picks up the painful injection theorem in order to deal more damage. Injection expert gets upgraded to make his attacks with injection weapons more accurate.
Level 3 (Soldier): Koth adopts the wrathful warrior primary fighting style, gains several skills as class skills, proficiency in heavy armor and shields. He also learns the weapon focus (advanced melee) feat.
Level 4 (Soldier): He takes the cleave feat.
Level 5 (Soldier): Increases his ability scores (STR +2 to 13; DEX +2 to 18; CON +2 to 14; WIS +2 to 16). Learns the spinning cleave feat boost, picks up toughness as his feat and gains weapon specialization in all weapons.
Level 6 (Soldier): Learns the powered armor proficiency.
Level 7 (Biohacker onwards): Koth gains spark of ingenuity. 
Level 8: New theorem, he learns strange anatomy.
Level 9: Koth’s custom microlab becomes more potent as it now functions as an advanced medkit. He also learns the breakthrough of her primary field of study. Finally he picks up the mobility feat.
Level 10: He increases his ability scores (DEX +1 to 19, CON +2 to 16; WIS +2 to 18; CHA +2 to 12). He also takes the Powered Armor Jockey archetype, granting him efficient upgrades.
Level 11: Gains a secondary field of study (toxicology), as well as learns the spring attack feat.
Level 12: Koth learns the elongation mutation theorem. 
Level 13: Koth’s custom microlab gets even more potent and can act as a medical lab and can interpret targets at a longer distance. His injection expert feature gets upgraded further. Instead of getting an extra use of the spark of ingenuity feature per day, his archetype gives him perfect fit. Finally, he learns the enhanced resistance feat.
Level 14: Learns the medication mastery theorem.
Level 15: He increases his ability scores (DEX +1 to 20, CON +2 to 18; WIS +1 to 19; CHA +2 to 14). Learns the secondary field of study breakthrough and picks up the close combat feat.
Level 16: Koth gains the boosted leverage ability of his archetype, making him far more powerful.
Level 17: Learns his tertiary field of study (genetics) and picks up the iron will feat.
Level 18: Learns the bleeding biohacks theorem. 
Level 19: Koth learns the lightning reflexes feat.
Level 20: He increases his ability scores (STR +2 to 15; INT +2 to 12; WIS +1 to 20; CHA +2 to 16). Additionally, he learns the ooze form theorem.

Shilling
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