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Pathfinder 2e - The Barbarian Handbook

Last Updated: November 18th, 2019

Disclaimer

I will use the color coding scheme which has become common among Pathfinder build handbooks.

  • Red: Bad, useless options, or options which are extremely situational.
  • Orange: OK options, or useful options that only apply in rare circumstances
  • Green: Good options.
  • Blue: Fantastic options, often essential to the function of your character.

Introduction

The Barbarian is all about getting angry and hitting stuff. Depending on your choice of Instinct, there are some thematic options which go a bit beyond "get mad and hit stuff", but the majority of the class is absolutely fixated on getting into a fight, getting really angry, and just absolutely wrecking everything in your way. The Barbarian is easily compared to the Fighter, and where the Fighter is a master of martial arms and armor, focusing on using the right techniques at the right time, the Barbarian is often more of a blunt instrument, often addressing problems with a simple mindset. In many ways the Barbarian is a one-trick pony, but when so many of your problems are nails it helps to have a really nice hammer.

I don't normally dicsuss the fluff text at the beginning of class entries, but I really wat to call attention to the Barbarian's entry because it's such a perfect explanation of the class. During combat encounters: angry and violent. During social encounters: angry and terrifying. While exploring: watching intently for an opportunity to become angry and violent. In downtime: carousing.

Mechanically, the barbarian is a Defender and Striker similar to the Fighter. However, unlike the Fighter you're largely locked into melee combat, so your role in the party is fairly limited. You have very little needs from your skills, leaving you ample opportunity to fill skill-based roles in your party, provided that your ability scores can support them. You're unlikely to be a Face due to the class's absolute disregard for Charisma (the word doesn't appear anywhere in the class's entry in the Core Rulebook).

Barbarian Class Features

Key Ability: Strength. Unsurprisingly, a class about getting angry and hitting things depends on Strength.

Hit Points: More hit points than anyone else.

Initial Proficiencies: A broad range of proficiencies give you everything that you need to succeed as a barbarian, and it's easy to expand some of those options with feats.

  • Perception: You start at Expert, putting you ahead of most characters for a long time, but you don't improve to Master until 17th level.
  • Saving Throws: Expert in both Fortitude and Will, and you have a mountainn of hit points to deal with failing Reflex saves.
  • Skills: Standard starting skills. You're locked into Athletics, but you can get quite a bit out of Athletics so it's a great choice anyway.
  • Attacks: Trained in simple, martial, and unarmed. Not terribly exciting, but you've got a full range of options and you may be able to access Uncommon weapons using racial feats.
  • Defenses: Trained in everything up to medium armor. Unfortunately, your proficiency improves very slowly, so your AC will lag behind other front-line martial classes at several points. You might even consider spending a feat to get Heavy Armor Proficiency, then retrain it around 12th level before your proficiency increases beyond Trained.
  • Class DC: There aren't many barbarian options which rely on your class DC, but many of the ones that do are very good.

Rage: The Barbarian's most defining capability. While raging you'll deal additional damage and gain some temporary hit points, but you'll take a minor penalty to AC (it's only -1; you'll be fine) and you can't use actions with the Concentrate trait, which prevents you from doing things that require a lot of mental focus.

Instinct: See "Subclasses - Barbarian Instincts", below.

Barbarian Feats: See Barbarian feats, below.

Skill Feats: Standard for everyone except the Rogue.

Deny Advantage: The Barbarian is fairly good at perception, but this provides a nice insurance policy. This makes you very effective against ambushes, and against enemies which rely on flanking like NPC rogues.

General Feats: Standard.

Skill Feats: Standard for everyone except the Rogue.

Ability Boosts: Standard.

Ancestry Feats: Standard.

Brutality: More proficiency with your attacks is great, and Critical Specializations Effects can really add a lot. You only get the Critical Specialization Effects while raging, but if you're fighting and not raging you're either in a fight than went way too long or you're not taking the fight seriously.

Juggernaut: More Fortitude saves is great, and you hit Master before any other class.

Weapon Specialization: More damage is always great.

Lightning Reflexes: Better saves never hurts, but you never go beyond Expert. You might consider Canny Accumen at high level to raise your Reflex Saves to Master.

Raging Resistance: When you get this, you should reasonably expect to have 18 Constitution, and 7 points of damage resistance is really good. You'll likely max out at 8, but that's still significant. The usefulness of this ability is defined by your Instinct, and the effects vary signficiantly.

Mighty Rage: In many ways, this makes Rage free. You'll need to have at least one feat which gives you an action with the Rage trait, but considering how many good options are available that's not a problem.

Greater Juggernaut: The Barbarian is the only class to reach Legendary in Fortitude saves.

Medium Armor Expertise: Finally, your AC improves! Your armor proficiencies improve at the absolute slowest rate, putting the Barbarian on part with the Wizard and similarly non-martial classes. Fortunately, you have d12 hit points and temporary hit points from Rage to compensate.

Weapon Fury: Always helpful, and the Barbarian matches the weapon proficiency progression of most martial classes.

Greater Weapon Specialization: More damage!

Indomitable Will: Better saves is always great.

Heightened Sense: Despite starting with unusually good Perception, this is the first time your Perception proficiency increases.

Quick Rage: A full turn is nothing. You can manage to be just baseline angry for 6 seconds between bouts of violent fury.

Armor of Fury: More AC never hurts, but this is very late for a martial class.

Devastator: Ignoring 10 points of resistance is a lot of extra damage against creatures which normally resist damage from your weapons.

Subclasses - Barbarian Instincts

Animal Instinct

Animal Instinct Barbarians are the monks of barbarians. They rely on unarmed attacks, gaining powerful new unarmed attack options based on their chosen animal. Nearly every unarmed attack granted by Animal Instinct exceeds most Monk unarmed attack options, and between Rage and strict reliance on Strength you'll often find that your unarmed attacks are more lethal, though without Flurry of Blows you'll perform less attacks than a Monk would. To address this, consider taking the Monk multiclass archetype feats. This is especially easy to do because the Animal Instinct-specific Barbarian Class Feats are awful.

When you select Animal Instinct, you must also select a type of animal. This determines the unarmed attack(s) you gain when you Rage, and can be a significant part of your build if you choose to rely upon your unarmed attacks. These attacks are often as good as or better than any one-handed weapon you could find, and they rarely require a free hand, so you're free to use a shield and to use your free hand for special attacks like grappling and shoving. Becuase you're not using a manufactured weapons, expect to invest in Handwraps of Mighty Blows like a monk would. Your choice of animal also affects how Animal Rage works, but Animal Rage is garbage, so don't worry about that.

  • Ape: Grappling is a great option, and having the Grapple trait on your unnarmed strikes means that you can add the bonus from Handwraps of Mighty Blows to your Athletics checks to grapple.
  • Bear: Having an Agile secondary weapon means that your additional attacks will be more effective, but using an Agile weapon halves the bonus damage from Rage, and when your Rage bonus damage is 12 per hit that's a lot of damage to lose for a minor reduction in your Multiple Attack penalty. Unfortunately, access to Agile claws costs you an interesting property on your bite. Animal Rage gets you essentially
  • Bull: Shove is neat, but very situational. You'll get more mileage from Grapple or Trip, and in the rare situations where you need to Shove you can Shove just like everyone else.
  • Cat: Idnetical to the Bear.
  • Deer: Slightly less damage than the Ape, but you get 10 ft. reach at 7th level in exchange. You also don't need a hand to make the attack, so you can use your hands for other stuff like high-fives and shields. Despite the tiny reduction in damage, I think gaining reach and not needing to use your hand is absolutely a fair trade. Note that the errata replaced the Charge trait with the Grapple trait, so if you're looking at the first printing Core Rulebook the text is incorrect.
  • Frog: Combining the interesting parts of the Bear/Cat and the Deer, the Frog gets a secondary Agile attack and eventually gets 10 ft. reach (at level 7, of course) with that attack, but doesn't have a useful trait on its primary attack. You're free to use jaws as your primary attack, then use your tongue when you can't or don't want to get withing 5 ft. of your target.
  • Shark: Mostly the same as Ape, but since jaws don't use your hand your hands are free, much like the Deer. Also, if you take Animal Rage you gain the ability to breath underwater while raging.
  • Snake: All the same benefits as the Shark, but you can't take Animal Rage to breath underwater. It's technically worse than the Shark, but Animal Rage is awful so realistically there's little difference.
  • Wolf: Trip is an absolutely fantastic trait.
  • Anathema: Be kind to animals. Not all animals; just ones of the type you picked. You can be a jerk to the rest.
  • Instinct Ability: Bestial Rage: The unarmed attacks granted by Betial Rage are fantastic, matching the effects of many two-handed weapons without requiring the use of your hands. However, since you're going to be so dependent on these attacks you'll be in a lot of trouble if you're in a fight and not raging.
  • Specialization Ability: More damage, and the Deer and Frog both get some reach on their attacks.
  • Raging Resistance: The two most common types of weapon damage. This is absolutely spectacular for a character who spends as much time in melee as the Barbarian does.

Dragon Insinct

Dragon Instinct is easily comparable to other Instinct options, but what sets it above other options is the Instinct-specific feats. Though there are only three feats, they're all good and they're all usable in any combat situation. Other Instinct options generally only have a handful of good feat options, and their best options frequently come with problematic limitations like the fact that you can't grow to Huge size in a 10-foot wide corridor. Dragon Instinct feats give you a breath weapon (both one of the Barbarian's best ranged attacks and one of the Barbarian's best ways to deal with crowds), easy access to flight, and eventually the ability to fully turn into a dragon while raging. However, you may find that you face issues with relying on a single type of energy damage which is determined by your selected type of dragon.

Your choice of patron dragon is an interesting choice. A less-common damage type like acid or lightning will be more usable offensively, but also less useful as a resistance. You also need to choose between a dragon which gives you a cone or a line, and you need to consider how your Anathema will interact with that type of dragon. I think everything balances out in the end, so you're probably fine selecting whichever dragon suits you.

  • Anathema: One of the more complicated options, you must also select whether you abhor (hate) or respect your dragon type. If you hate them, failing to defeat dragons of your chosen type is anathema. Conveniently, your Anathema doesn't compel you to confront, fight, or intentionally oppose them, and as long as you never try you can never fail. If you choose to respect your dragon type, merely defying dragons of your type is Anathema, so if a dragon of your type shows up your character may accidently become a slave.
  • Instinct Ability: Draconic Rage: Extra damage is always great, and the energy damage will frequently bypass resistances to physical damage. If you encounter an enemy which is resistant to your dragon's damage type, don't forget that you can choose to not use Draconic Rage when you initiate a rage and fall back on the normal Rage damage bonus.
  • Specialization Ability: More damage is always nice.
  • Raging Resistance: Piercing damage is common from bites and similar attacks.

Fury Instinct

The most generic of options, Fury Instinct works fine, but doesn't do anything expecially exciting. If you just want an uncomplicated barbarian, you'll do well with Fury Instinct.

  • Anathema: You don't get one.
  • Instinct Ability: : You don't get one. Instead, you gain an extra 1st-level Barbarian feat, which is nice. Unfortunately there aren't many options to choose from and you may not be able to use all of them in a meaningful way. As more options are published, this will become more useful.
  • Specialization Ability: More damage is great, but since it's all you get it would be nice if the bonus were bigger. By comparison, Spirit Instinct does 1 more damage, and it's an interesting damage type too.
  • Raging Resistance: Broadly useful, but since it only applies to weapon damage it won't protect you from things like unarmed attacks (claws, teeth, etc.).

Giant Instinct

Giant Instinct's initial draw is that you get to use a gigantic weapon. That's neat, but not actually impactful from a mechanical perspective. The real draw here is the Instinct-specific feats. As you progress, you'll gain the ability to increase your size when you rage, as well as increasing your reach. Look at complementary options like reach weapons and the Whirlwind Attack feat, and be cautious pursuing this Instinct if your GM likes to use lots of dungeons with small rooms and narrow corridors where you won't be able to grow in size.

  • Anathema: You must face any "personal challenge of Strength". The text isn't totally clear what that entails, but I think if someone were to say "I bet you can't drink that whole barrel of wine" you're obligated to at least try, even if you're certain to fail. Hopefully your party isn't a bunch of jerks, or they might abuse this to convince you to jump into pits and attempt other suicidal activities.
  • Instinct Ability: Titan Mauler: You gain access to one weapon of a larger size. You still need to buy it yourself out of your starting money, and you only get access to one so you'd better not lose it or break it. You're Clumsy 1 while using this weapon, which essentially means that you're taking a -1 AC penalty to get 4 extra damage from Rage. That's probably a fine trade, but be sure to focus on improving your durability to compensate.
  • Specialization Ability: Even more damage!
  • Raging Resistance: An interesting combination of options. Bludgeoning damage is the least common type of damage typically dealt be weapons, but you get Fire as an option, and Fire is extremely common. If you already have resostance to Fire damage, get Cold instead.

Spirit Instinct

Spectacular against undead, and still perfectly functional against other foes, but not especially exciting. You do get access to some Instinct-specific feats like Spirit's Wrath, but they're not good enough to set Spirit Instinct ahead of other options.

  • Anathema: Disrespecting the dead is easy to avoid. Even looting, skinning, and eating a corpse can be done respectfully.
  • Instinct Ability: Spirit Rage: A little bit more damage than normal, and you can make it Positive or Negative damage, which means that few enemies will be able to resist it. You also gain the effects of the Ghost Touch weapon rune, which is great. Ghost Touch is powerful and inexpensive, so it's a staple of melee builds, but it also eats one of your limited slots for property runes.
  • Specialization Ability: More damage is always nice.
  • Raging Resistance: Negative damage is rare, and while resisting all damage from undead is great it's also only one creature type.

Ability Scores

There is almost no variation in Ability Score spread between barbarian builds. Unsurprisingly, you need a ton of Strength, some Dexterity to fill our your medium armor's Dex Cap, Constitution to improve your hit points, and Wisdom for Perception and Will Saves.

Str: Your defining ability. Start at 18 and boost it at every opportunity.

Dex: How much Dexterity you need varies only slightly by build. Most barbarians will be in Breastplate, so you'll need no more than 12 Dexterity. Animal Instinct barbarians will need as much as 16 once they take Animal Skin at 6th level, but you can start with 14 and increase it at 5th level if you want to put your boosts elsewhere.

Con: You need as much as you can get. Start at 16, and boost it at least until you hit 20.

Int: More skills doesn't hurt, but don't go crazy.

Wis: Perception and Will Saves.

Cha: Dump. Worthless unless you go out of your way to invest in skills and feats which are Charisma-based.

Ancestries

Strength and extra hit points are crucial, so a race that can give you both a Strength Boost and a Constitution Boost are great, and high starting hit points never hurts. If your race offers you the option, you might enjoy access to some Uncommon weapons, but you'll do fine without them. Also look for other ways to make yourself more durance, like racial damage resistances or racial feats which can purther raise your maximum hit points. Finally, Darkvision is a fantastic option because it opens up Acute Scent without requiring you to waste a feat on Acute Vision.

Dwarf: Constitution, Wisdom, and the Free Boost goes into Strength, Darkvision, and maximum starting hit points. Ancient-Blooded, Forge, and Strong-Blooded all improve your durability further. Unfortunately, Dwarf Ancestry Feats offer very little that we want. Dwarven Weapon Familiarity is tempting for a free-hand build if you want to use a Dwarven War Axe instead of a Bastard Sword, and Mountain's Stoutness offers additional hit points and helps you stabilize while dying, both of which are helpful for barbarians. I strongly recommend Adopted Ancestry to get broader Ancestry Feat options, and definitely take Toughness to get the combined effect with Mountain's Stoutness. Since the Dwarf has such poor base speed, consider the Fleet general feat, or the Fast Movement Barbarian Class Feat.

Elf: The lowest starting hit points, a Constituion Flaw, and we don't care about either Ability Boost. The Elf's Ancestry Feats offer nothing that the Barbarian cares about.

Gnome: Possible, but very difficult. The Strength Flaw needs to be address with the Optional Flaw rules, and there is very little to be gained the Gnome's Ancestry Feats. One notable exception is the Gnome Flickmace, which you can make into a Martial weapon with a the Gnome Weapon Familiarity feat. If you want to go that route, I would still suggest Adopted Ancestry and using a different Ancestry to get the feat.

Goblin: You might be able to manage a Dragon Instinct build, and capitalize on the Charisma Boost to use Intimidation and possible other Face skills, but the Goblin has the lowest possible starting hit points and few Ancestry Feats that we care about. Even Burn It! isn't helpful since it only applies to spells and alchemical items.

Halfling: I recommend using the Optional Flaw rules to get an extra Free Ability Boost so that you can boost both Strength and Constitution, but otherwise the Halfling is a decent option. There aren't many useful Ancestry Feat options, but there are enough that you don't absolutely need Adopted Ancestry. Hillock Halfling offers a way to get some extra healing out of Treat Wounds, which is great on a class that's notorious for burning through a huge pile of hit points.

Human: Humans, especially half-orcs, are a great option. Natural Ambition will get you some extra options at 1st level, and beyond 1st level you have lots of ways to customize and expand your capabilities.

Backgrounds

Boosts to Strength and Constitution are too important to accept anything else, which can severely limit your options, but there are still plenty of great options to choose from. Avoid backgrounds which give you skill feats in Charisma-based skills, even though this rules out options like Guard and Warrior which fit the class thematically.

If you're having trouble deciding, here are some suggestions:

  • Bounty Hunter
  • Laborer (you get to replace Athletics since you get it as a Barbarian at 1st level)
  • Miner

Skills

  • Acrobatics (Dex): Situational, but your Dexterity won't be terrible.
  • Arcana (Int): Best left to someone equipped to do something about magic beyond responding with violence.
  • Athletics (Str): Used for grappling and shoving, and you get it automatically.
  • Crafting (Int): Typically best left to someone smarter than you, but crafting can be a fun and interesting way to enjoy the Downtime rules.
  • Deception (Cha): You are not a Face.
  • Diplomacy (Cha): You are not a Face.
  • Intimidation (Cha): I really wish that it was easier to make Intimidation work for the Barbarian because it makes so much sense for the class, but one skill is not enough to justify putting resources into Charisma.
  • Lore (Int): A possibility if you didn't dump Intelligence.
  • Medicine (Wis): Your Wisdom is decent, and this is one of your only options for additional healing beyond resting.
  • Nature (Wis): You have the Wisdom to make it work.
  • Occultism (Int): Knowledge skills are always helpful, but I would only take this if noone else in the party has it for some reason.
  • Performance (Cha): You are not a Face.
  • Religion (Wis): You have the Wisdom to make it work.
  • Society (Int): Knowledge skills are always helpful, but I would only take this if noone else in the party has it for some reason.
  • Stealth (Dex): A possibility if your Dexterity is decent.
  • Survival (Wis): You have enough Wisdom to be passable, but skip it if your party has a Druid or a Ranger.
  • Thievery (Dex): A possibility if your Dexterity is decent.

Feats

Barbarian Feats

1st Level
  • Acute Vision: Helpful, but until you rage you're either stumbling around in the dark, carrying a light source, or you already have Darkvision. This effect isn't bad; the problem is just that you can only use it while raging, which requires someone to inflict violence upon for it to remain in effect.
  • Moment of Clarity: It's too easy to avoid options with the Concentrate trait to justify a feat and an Action to use this.
  • Raging Intimidation: If you're building with enough Charisma to justify Intimidation, this is great. Otherwise, it's worthless.
  • Raging Thrower: Put a Returning rune on a weapon and you're good to go. Of course, most barbarians won't have more than 12 or 14 Dexterity, so ranged attacks aren't typically a good go-to option. If you intend to rely on throwing things, be sure to use a weapon with the Thrown property like the Trident.
  • Sudden Charge: If you're going to Stride and Strike (a combination of actions which you'll do frequently throughout your career), you might as well get some more distance out of your two Actions.
2nd Level
  • Acute Scent: Imprecise Scent is the Barbarian's best option for handling hidden and invisible foes.
  • Furious Finish: Garbage. Absolute garbage. The damage bonus is small and will become irrelevant quickly as you gain levels and acquire additional damage bonuses.
  • No Escape: A great way to keep enemies in melee with you, but it may also pull you out of position to protec your allies. If you take this, consider retraining it once you can get Attack of Opportunity since they both trigger on the same effect and you still only get one Reaction per round.
  • Second Wind: A great fallback option, and with the prevalence of Focus Spells you're likely to spend 10 minutes after every fight standing around while your allies Refocus. Once you get Quick Rage at high levels this becomes redundant, so be sure to retrain it.
  • Shake it Off: Frightened goes down by 1 automatically at the end of every turn, and you can already attempt an Action to reduce your Sickened level. This makes that Action much more effective, but that's far too situational to justify a feat.
4th Level
  • Fast Movement: More movement is always helpful for a class that functions almost exclusively in melee. This provides a Status bonus while raging, so it might not stack with spells and similar effects, but it stacks with the Fleet feat.
  • Raging Athlete: Climb and Swim speeds allow you to move easily in a variety of environments, allowing you to overcome many obstacles which normally require magic or struggling along with Athletics checks.
  • Swipe: A great way to handle groups of weaker foes, which is normally difficult for martial characters. While it's technically situational, it's a common situation to be in. If you take this, I strongly recommend a weapon with the Swipe trait.
  • Wounded Rage: A great way to save yourself an Action on your next turn. Sadly the Temporary Hit Points from Rage don't apply until you've already taken the damage.
6th Level
  • Animal Skin: This works out to +1 AC compared to other barbarians, but you need to be unarmored and raging, which makes you susceptible to ambushes and further exacerbates Animal Instinct's issues fighting while they are unable to rage. However, if you multiclass into Monk you may be able to combine this with Mountain Style to have a ridiculously high AC. That's hard to do because you'll need to spend two Actions to get set up at the beginning of combat, but it may be worth it to make yourself so difficult to kill.
  • Attack of Opportunity: Almost too powerful to forgo. Pathfinder 2e doesn't allow you to respond to moving enemies by default, so they are often free to walk right past you to attack your less-durable allies.
  • Brutal Bully: If you're going to use special attacks like grapple and trip anyway, more damage never hurts.
  • Cleave: Great, but possibly redundant with Swipe, and the Multiple Attack Penalty works as normal, and your eating your Reaction so you won't be able to use Attack of Opportunity if you have both feats.
  • Dragon's Rage Breath: Barbarians get very few options for handling crowds of enemies. This will keep pace with the damage of spells until extremely high levels, and the save DC will be high because your Strength will be so high. The limitation on one usage per rage and the 1-hour cooldown on the full damage are both disappointing, but this is still really good. Even against single foes, the amount of damage you can do to a single target can easily exceed the damage you would do by swinging a weapon with the same two Actions.
  • Giant's Stature: -1 to AC is probably the only drawback that you care about from Clumsy. Large size makes you take up a 10 ft. square, and combined with the additional 5 ft. of reach you can control a much larger portion of the battlefield. Of course, this is considerably more useful if you take Attack of Opportunity first, and unfortunately they both become available at the same level.
  • Spirits' Interference: Situational, but a 20% miss chance on all ranged attacks against you can be really useful against archers, spellcasters, and other creatures that fight at range.
8th Level
  • Animal Rage: The only benefits you get are the movement types (which are worse than Raging Athlete in most cases), and potentially the ability to breath water if your animal type is Shark. Absolutely not worth a feat.
  • Furious Bully: +2 is not a big bonus, and if you're this concerned about Athletics you can make it the first skill you increase at any opporunity, then take Assurance with Athletics. That, combined with your incredible Strength, should allow you successfully grapple or shove most foes without issue.
  • Renewed Vigor: By this level, the extra temporary hit points are insignificant. Enemies will go through them too quickly to matter. You would be better served by spending your Action on nearly anything else.
  • Share Rage: Potentially useful if you have another similar martial character in the party, the +2 damage per attack from your ally almost certainly won't match whatever damage you could do with the same Action. By this level you'll reasonably have a Striking rune on your weapon and you have Weapon Specialization, so you could easily be doing 2d8+2+Strength damage. With 19 Strength (expected at this level), that's 2d8+6 damage, averaging 15 damage (assuming that you hit, of course). Your ally needs to hit at least 8 times before your Rage ends to justify the Action. Your damage from your attacks will continue to improve as you gain levels, but Share Rage won't because Rage never actually improves. Your own bonuses improve, abd you get Mighty Rage, but Share Rage doesn't spread those benefits.
  • Sudden Leap: An interesting way to handle flying enemies, but it's very situational, and by this level magical flight is easily accessible by your party's spellcasters.
  • Thrash: A decent, safe us for an Action. Grapple has the Attack trait, so Multiple Attack Penalties become a problem. Thrash isn't an attack, so it's nearly-guaranteed damage. You'll do more damage with a weapon if you hit, but Thrash is a helpful choice if you're already looking at a steep Multiple Attack Penalty. Unfortunately, as you add better Striking runes, your weapon damage will significantly outpace the damage from Thrash. Note that errata corrected the text "Ferocious Specialization" to "Weapon Specialization", so your Weapon Specialization damage bonus applies. Unfortunately, nothing specifies what level of proficiency you use to determine your damage bonus in this case. I assume it's the one for Unarmed Strikes, but your proficiencies are all the same unless you got access to Advanced Weapons somehow.
10th Level
  • Come and Get Me: This is a big gamble, and I'm not certain that it pays off. Use with caution. There are nearly no "taunt" mechanics in Pathfinder 2e, so this may be worthwhile solely because it motivates enemies to attack you instead of your allies.
  • Furious Sprint: Too situational. Get a horse instead.
  • Great Cleave: Too situational. Unless your GM loves to throw hordes of weak enemies at you, you'll nearly never see a benefit from this.
  • Knockback: Not worth the feat. If you care enough to take this, use a weapon with the Shove trait and put some effort into Athletics.
  • Terrifying Howl: This feat on its own is fantastic, but Charisma (and therefore Intimidation) is hard to justify for the Barbarian, You could also take the Battle Cry feat, which makes Terrifying Howl much less interesting. Note that errata changed the text from "every creature" to "every enemy" so you no longer need to worry about scaring your allies.
12th Level
  • Dragon's Rage Wings: Free, easily-accessible flight! Absolutely essential at high levels.
  • Furious Grab: Grappling is really helpful, but if you enjoy grappling you're already deeply invested in Athletics, so this will only rarely have a better result than spending an Action to grapple your target in the normal manner.
  • Predator's Pounce: Similar to Sudden Charge, but since it's a single Action it's more flexible. Unfortunately, you need to be unarmored or in light armor. The assumption is that Animal Instinct barbarians will rely on Animal Skin, but Animal Skin is terrible. If you plan to take this, boost your Dexterity to 16 to max out light armor.
  • Spirit's Wrath: An absolutely respectable ranged attack option for a class which is notoriously terrible at fighting at range. Your damage almost certainly won't match your weapon damage, but you can't swing a sword at something 120 ft. away.
  • Titan's Stature: More size and more reach! You may have some trouble in closed spaces like dungeons, but if there's room to get big you can easily dominate entire rooms.
14th Level
  • Awesome Blow: This would be totally worthless if you couldn't also Trip the target. If you're invested in Athletics (Assurance, increased the skill as early as possible, etc.) you can reliably Shove and Trip enemies with a single action without incurring a Multiple Attack Penalty beyond the initial successful Strike. Of course, if you don't benefit from the Shove, you would do just as well simply making a Trip action and saving the two feat spent on Knockback and awesome Blow.
  • Giant's Lunge: More reach never hurts, but if you're building for reach you've likely gotten very attached to polearm by now. But if you really want to use a shield, having 10 ft. reach with one-handed weapons may be enough to justify the feat.
  • Vengeful Strike: Good enough to make Come and Get Me a go-to option.
  • Whirlwind Strike: Imagine combining this with Titan's Stature. It's three Actions so you'll need to be in position at the start of your turn, but if you can hit at least three enemies it's considerably more effective than making single strikes. Strongly consider a weapon with the Sweep trait in conjunction with this feat.
16th Level
  • Collateral Thrash: This doubles the total damage output from Thrash without changing the action required. This makes Thrash an interesting alternative to Swipe, and since it's not an attack (and therefore doesn't impost a Multiple Attack Penalty) it makes a grat follow-up to a Strike or two. Or you could just thrash two or three times in one turn if you find that it's working well for you.
  • Dragon Transformation: You get a lot from this. Flight, scent, darkvision, powerful unarmed attacks, a breath weapon, and possibly other movement types like a burrow speed or a swim speed. However, since you're making unarmed attacks you're giving up the benefits of your well-enhanced magic weapons. Consider putting some gold into a cheap set of Handwraps of Mighty Blows for an easy attack bonus. Your attack bonus with Unarmed Strikes should be +22+Strength, easily exceeding the flat +22 provided by the spell, and any extra bonus on top of that just adds to how effective this is. It's unclear how or if Runes of Striking interact with the spell, but for simplicity I would assume that they don't. Note that errata corrected the final paragraph of the feat: You no longer get a fixed DC of 30. Instead, you always use your Class DC for the breath weapon.
  • Reckless Abandon: This is a big gamble to make when you're already injured. Attack bonuses are significant, but you take an equivalent penalty to AC and a penalty to saves, so you're likely to increase the amount of damage you take faster than the amount of damage you deal. Still, you might combine this with Come and Get Me and Vengeful Strike to really draw attention to yourself, and rely on the temporary hit points from Come and Get Me to keep you alive.
18th Level
  • Brutal Critical: A single extra damage die on a critical hit is nothing at this level. Your Strength is above 20, and your attacks should deal 3 or 4 dice of damage (Rune of Major Striking is a 19th-level item, so you probably don't have one yet but they're right around the corner). The real benefit is the two dice of bleed damage. If you're swinging a weapon that deals d10 or d12 damage, that will add up quickly.
  • Perfect Clarity: Will Saves are your weakest save, and the ability to reroll them makes you dramatically more resilient. You'll end your Rage prematurely, but you got Quick Rage at level 17, so you'll only go without raging for one turn. Considering this could easily save your life, giving up Rage for one turn seems like a fair trade.
  • Vicious Evisceration: This is for monsters and NPCs. Unless you plan to fight the same creature multiple times in the course of the same day with ample time for everyone to heal between fights, this will effectively deal extra damage equal to the target's level (double its level if you scroe a critical). This costs two Actions. Instead, you could make two Strikes, and assuming you're using something at least as damaging as a longsword you should be doing at minimum 3d8+11 (+5 Str, +6 Greater Weapon Specialization; Avg. 24.5), and that doesn't account for Rage or additional damage from property runes or other effects. Unless the target's level significantly exceeds your average damage or the target has some way to heal to full health, I don't see a scenario where this is worth such a high-level feat.
20th Level
  • Contageous Rage: You're unlikely to use tyis more than once or twice in a single rage, depending on your party. By this level you have Quick Rage, and since this action has the Rage trait you can use the same Action to make yourself and an ally Rage. Your ally gets to choose whether or not to accept your Anathema, but they would need to be a in a truly bizzarre circumstance to decline. I think your party can manage to behave themselves for a minute at a time, especially with a fight to distract them. The exact benefits of this decision vary depending on your Instinct. If you selected Animal Instinct, your ally is unlikely to benefit from the improve unarmed attack unless they are a Monk. If you chose Giant instinct, your ally is almost certainly unable to benefit because they are unlikely to use a "larger weapon" unless they are also a Giant Instinct Barbarian.
  • Quaking Stomp: An 8th-level spell, and you can use it at half the normal Action cost (1 Action instead of 2 Actions) every 10 minutes.

General Feats

  • Armor Proficiency: You are only Trained in medium armor until 13th level, giving you 12 full levels at which this feat will let heavy armor match your proficiency with medium armor. You could take this at low levels, enjoy heavy armor for a long time, then retrain the feat at level 12 or 13 and switch to medium armor if you want to do so. That also gives you time to increase your Dexterity at levels 5 and 10 if you need to do so.
  • Canny Accumen: A great way to improve your proficiency in Perception or your weakest save, but you don't get to Master until 17th level so it's easy to delay.
  • Shield Block: A shield can add a lot to your durability, and considering the Barbarian's relatively poor AC that may be enough to justify the feat.
  • Toughness: You already have more hit points than anyone, but the Barbarian tends to have worse AC than other front-line melee characters, so you need hit points to compensate.

Skill Feats

  • Assurance: Assurance in Athletics offers you a lot of wonderful options.
  • Battle Medicine: Despite the Temporary Hit Points granted by Rage and your massive pool of hit points, an easy way to heal yourself may still be a good idea. The Barbarian tends to burn through hit points rapidly due to their relatively poor AC, and a way to heal yourself in combat can be a big help. The amount healed can rise as you improve your proficiency with Medicine, keeping this a relevent and useful option as your maximum hit points rise steadily over time.
  • Titan Wrestler: If you plan to rely heavily on grappling, this is essential.
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Weapons

Because your options for weapons are so broad, it's difficult to make specific recommendations. Instead, I'll offer some general advice on common Martial Weapons, and I'll discuss some Uncommon and Advanced Weapons which offer some interesting options to the characters who can access them.

Your first decision is whether you will use one-handed weapons and a shield, two-handed weapons, or a one-handed weapon and a free hand so that you can use your free hand to grapple and perform other special attacks. Animal Instinct Barbarians will largely disregard this decision in favor of making unarmed attacks, but be sure to pick up a ranged weapon which you can throw.

If you choose a one-handed weapon and a shield, you're choosing to improve your durability at the expense of offensive capability. Consider feats like Shield Block to make the best possible use of your shield, and consider multiclassing into Fighter to get extra options for your shield. You can still use weapons with traits like Trip and Shove to perform those special attacks without a free hand, so consider weapons like the Flail if you plan to make use of special attacks on a regular basis. If your party doesn't have good options for dealing with crowds of weak enemies, look for weapons with the Sweep trait like the BAttle Axe. If you're not sure, the Longsword is a perfectly fine option.

If you choose to use two-handed weapons, you're choosing to focus on damage output over durability. This is generally an expectation for the Barbarian, but if you're going this route be sure that your party has adequate healing options available. Consider feats like Toughness, and consider the Medicine skill and related Skill Feats if your party can't constantly supply you with magical healing. Your choice of weapons is very similar to one-handed weapons, but you have the option of a weapon with Reach. If you really enjoy special attacks, the War Flail combines several excellent traits. If you just want to hit stuff, go for a Greatsword.

If you choose to fight with an open hand, any one-handed will do fine, but you might also consider the Bastard Sword. The Bastard Sword, when used two-handed, deals a much damage as the Greatsword, but you have the option to use it one-handed so that you can use your other hand to grapple or hold items or whatever else. However, if you don't intend to Grapple you'll be better server by using a weapon with the appropriate Trait so that you can apply your weapon's Item Bonus to your checks.

Uncommon Martial Weapons and Advanced Weapons

  • Gnome Hooked Hammer: Great for an empty-hand build becuase you can use it two-handed for extra damage, and it also has the Trip property so you can get the Item Bonus to checks to trip things.
  • Horsechopper: Basically a Guisarme, but it does less damage in exchange for Versatile. That would be a fine trade if it didn't also cost feats to get access to the Horsechopper.

Armor

  • Padded Armor: Good starting armor if you plan to rely on Animal Skin exclusively for your AC, but otherwise go for medium armor.
  • Hide: Your likely starting armor.
  • Breastplate: Probably your permanent choice of armor.
  • Half Plate/Full Plate: If you decide to go for heavy armor, you'll probably still start with Hide because heavy armor is so expensive. If you have 12 Dexterity and plan to eventually return to medium armor once your proficiency improves, stick to half plate. Otherwise, consider spending the extra gold on full plate.

Magic Items

Other Magic Items

  • Berserker's Cloak: Putting runes on Handwraps of Mighty Blows is more cost-effective for Animal Instinct Barbarians, and using a weapon is more effective for everyone else.
  • Handwraps of Mighty Blows: As crucial for Animal Instinct Barbarians as a weapon is for every other type of barbarian.

Archetypes

In general, avoid archetypes which provide spellcasting. The inability to use actions with the Concentrate trait during a rage makes spellcasting difficult to rely upon, especially in combat when your feats are most important.

  • Alchemist: Conceptually tempting, since mutagens seem like a fun way to supplement Rage, but the benefits are mostly redundant. Animal Instinct Barbarians are likely to consider Bestial Mutagen, but the unnarmed attacks will be worse than what you get while raging. Juggernaut Mutagen also looks tempting, but you get more Temporary Hit Points from Rage. Both mutagens grant items bonuses, but they won't stack with essential items like Handwraps of Mighty Blows and fundamental runes on your armor. You might gain some benefit from crafting elixirs, but if you just need cheap healing it's
  • Fighter: The Fighter has a lot of great options for the Barbarian, and since so few Fighter feats have the Concentrate trait, almost all of the Fighter's feats are options for you. Feats which take a single Action to make a Strike and gain some other benefit like grabbing or shoving the target can help maximize your action economy, allowing you to use your favorite special attacks without costing potential Strikes. Fighter Class Feats also make two-weapon fighting builds a possibility, but I'm not certain that they're worth the feat investment. Avoid Power Attack; Rage's damage bonus applies to each hit, so you'll get better damage output from making extra Strikes. Similarly, be wary of Stance feats, as the Action investment to both Rage and start a Stance at the beginning of a fight can cut into crucial damage output early in a fight when it's most impactful.
  • Monk: Absolutely stellar for Animal Instinct barbarians. Powerful Fist is helpful when you're unable to rage, and many Monk Feats offer fantastic ways to complement your unarmed attacks. Stance feats can be a hard choice because spending two actions to get set up in the first round of combat can be hard until you have options like Quick Rage and Predator's Pounce. Take Monk's Flurry as soon as possible so that you can get even more mileage out of your absurdly powerful unarmed attacks. Barbarians with instincts other than Animal will likely be better served by the Fighter.