Karlach Build - Avernus Avenger - Baldur's Gate 3 (BG3)

Karlach Build - The Avernus Avenger

Karlach is probably one of the most favoured companions in the game. Although at first she presents herself as a cruel and hotheaded fighter, getting to know her reveals a softer side. The build aims to cover and use her backstory to create a functional and truly strong build. You can freely use this one even on the hardest difficulties

The main choices I made here are to pick these classes and subclasses:

• Rogue with Thief subclass - represents her early year,s where she did odd jobs to help her family. This does not mean that she was a pickpocket, but being versatile in various things helped her earn Fast Hands. The additional bonus action will be extremely useful for Frenzy​. Otherwise, Berserker (her default subclass) becomes irrelevant.
• Fighter with Battlemaster - shows her experience of serving Gortash as a bodyguard, but also general experience in combat situations. This will give Action Surge​ and other goodies to greatly improve combat capacity.
• The Barbarian Berserker - is there for when she was in Avernus with her Infernal Engine. It somewhat represents the insanity of prolonged war and combat, and what she had to go through to live with this mechanical thing in her body. Frenzy​ will be the core feature

So this allows us to build not just lore-friendly Karlach, but also an effective frontliner, with lots of tools under her belt. This means you will constantly unlock new features as you progress through the game.

I would say this build is aimed more at those who play the game for the first time and want a simpler experience without difficult mechanics.

So let's jump into the build!

Class Contribution

Here are what contributions and benefits you get from the class picks:

5 Barbarian Berserker

• Rage​ and its upgrade Frenzy​, for resistances, slight damage boost and a few other minor improvements.
• Unarmoured Defence​ - gives an armour class boost based on Constitution modifier, while not wearing armour.
• Reckless Attack​ - both a reaction and action, giving an easy advantage on attack rolls, greatly improving the early game combat capabilities
• Danger Sense​ - is a cool free upgrade that helps resist a lot of spells, especially those targeting ground effects.
• Unlocks a bonus action attack - Frenzied Strike. Sadly, it inflicts Frenzied Strain​ on each hit, and competes with Great Weapon Master: Bonus Attack​. Still, it's a good option to have as a fallback for additional attacks per turn.
• Extra Attack​ for one more hit using the main action point.
• Fast Movement​ is a totally free upgrade, giving a significant mobility improvement.

4 Rogue Thief

• Use a Sneak Attack (Melee)​ for a slight damage boost, once per turn.
• Additional Expertise,​ which will be used to improve Sleight of Hand.
• Special bonus action use - Cunning Action: Dash, Cunning Action: Hide, which help with engaging and running away for pickpocketing.
• Fast Hands​ is a very important feature, giving an additional bonus action. This can also be used to leave combat, improve mobility, or attack one more time.

3 Fighter Battlemaster

• Second Wind​ for a slight HP restoration, although most of the time it is more economical to use healing potions.
• Fighting style, to give a slight stat boost.
• Action Surge​ for an additional full action point, for a larger number of attacks.
• Access to Battlemaster manoeuvres, my favourite ones - Precision Attack, Disarming Attack (Melee)​ and Pushing Attack. There are many others to choose from, but these are my top 3.

Build Variations

Here are some variations that work similarly and utilise the same classes at their core.

Synergy with other builds

As the build takes the role of vanilla frontline combatant, it has a few niches where it can fit very well. Otherwise, I would not worry too much about how it is used:

Piercing Setup

A powerful melee weapon option for the late game, the piercing damage type, namely, Nyrulna, Shar's Spear of Evening, etc. They can have their damage doubled in Act 3 thanks to the Bhaalist Armour and its special passive effect - Aura Of Murder. With this in mind, you can build your party around to significantly increase the damage output and trivialise many of the game fights

• Melee martials with piercing weapons - Bardadin, Battle Master, Sorcadin, Bladelock, or any other melee option. They can go in close range with Bhaalist Armour equipped and apply Aura Of Murder​. This way other party members can enjoy the benefits of piercing vulnerability.
• Ranged builds can also benefit from Aura Of Murder​, as their weapons deal piercing damage - Hunter Ranger, Arcane Archer, Sword Bard Archer, Gloomstalker Assassin, etc. Of course, they can also have Bhaalist Armour equipped, but this increases their risk, and also applies Threatened,​ which reduces attack rolls.

Controllers

Almost any party can benefit from good controllers that use Hold Person, Glyph of Warding: Sleep,​ or Hold Monster. They guarantee a 100% critical chance and allow you to maximise the whole group's damage.

• Fire Sorcerer - one of the most reliable builds for this type of setup, with Hat of Fire Acuity + Scorching Ray​ to build Arcane Acuity. After that, use the control spell with a 100% success chance.
• Spellsword build - Sorcadin, Bardadin, Swords Bard Archer is the standard option for gish controllers, as they get access to Band of the Mystic Scoundrel + Helmet of Arcane Acuity for a very high spell success chance, and the already mentioned spell options.
• Lorecerer - similar to Fire Sorcerer, can use the same combo and can easily apply total control. Sadly, it is just limited to Hold Person and Glyph of Warding.
• Other caster-related builds - Lore Bard or even Arcane Trickster with access to unlimited scrolls. They get nice features that help them improve their spell success chance.

Leveling Overview

Here is a concise table with all the main picks during your levelling progression. For more detailed reasoning, I go further in the article. Also, do not forget to check the recommended gear, as it is crucial and can drastically change how the build works.

Level	Class	Selection
1	Barbarian 1	Abilities: Natural Strength setup: STR - 16 (14+2), DEX - 16 (15+1), CON - 12, INT - 8, WIS - 8, CHA - 14 Strength Elixir setup: STR - 8, DEX - 16 (15+1), CON - 14, INT - 8, WIS - 10, CHA - 17 (15+2)
		Skills: Any
2	Barbarian 2	-
3	Barbarian 3	Subclass: Berserker
4	Barbarian 4	Feat: Great Weapon Master: All In​ or Ability Improvement - Strength +2
5	Barbarian 5	-
6	Rogue 1	Abilities: any
7	Rogue 2	-
8	Rogue 3	Subclass: Thief
9	Rogue 4	Feat: Savage Attacker, Ability Improvement - +2 Strength, Sentinel: Vengeance​
10	Fighter 1	Fighting Style: Defence​
11	Fighter 2	-
12	Fighter 3	Subclass: Battlemaster
		Manoeuvre: Precision Attack, Disarming Attack, Pushing Attack​

Starting the Game - Level 1

This section covers the creation screen and what would go into the best Races, Abilities, and Skills for the Karlach build. If you have already started playing, feel free to do a respec at Withers and follow along. This will make it easy to follow the build step by step.

Origin

If you want to play Karlach as the main character, you would choose her in character creation

Races

Picking a race provides various benefits - abilities, dialogue options, looks, etc.

Race	Features	Description
Zariel Tiefling	Darkvision​ Hellish Resistance​ Thaumaturgy​	Karlach's race is Zariel Tiefling. They come with a wide variety of features, and as the level increases, unlock special smites - Legacy of Avernus: Searing Smite​ and Legacy of Avernus: Branding Smite,​ which give a slight damage boost. The main highlight is Thaumaturgy,​ which gives a free advantage on intimidation checks.

Class

Overview
Barbarian
Features
Rage​	Unique action to Barbarians that boosts damage and gives physical resistance. Make sure to attack each turn to sustain the bonuses.
Unarmoured Defence​	Gives some utility to the Constitution when going with Barbarian. Sadly, the build relies on various armors so this will not be utilized to the full extent.

Background

Backgrounds serve a few purposes:

1. They give a role-playing option of your previous history, if you are into that.
2. It gives skill proficiencies, meaning that you get an additional bonus when you roll that skill check in which you are proficient. This depends on your proficiency bonus, which increases as you level up.

Here are my recommendations based on this build

Abilities

Now, let's take a look at the abilities of the Karlach Berserker build. Correct allocation will allow you to maximise the early gameplay and get good modifier bonuses.

Abilities	Description
Recommended Setup: Strength - 16 (14+2) Dexterity - 16 (15+1) Constitution - 12 Intelligence - 8 Wisdom - 8 Charisma - 14	This is what I would recommend, for base setup, for those that do not want to use Elixir of Hill Giant Strength (well, Karlach seems like a person who would not use them). Charisma will play an important role in improving damage for Arcane Synergy. I would also recommend saving Auntie Ethel Hair for another companion.
Strength Elixir setup: Strength - 8 Dexterity - 16 (15+1) Constitution - 14 Intelligence - 8 Wisdom - 8 Charisma - 17 (15+2)	For minmaxers, this is the way to go. Elixir of Hill Giant Strength solves the strength question, and pumping charisma will give a significant damage boost later down the road. You can use either Patriar's Memory or Auntie Ethel Hair +1 Charisma for 18.

Skills and Expertise

Overall, the skills should be impacted by your role-playing and background decisions. However, you would still want those who will give you the best benefits. My recommendations are to pick those at which you have a high ability modifier or are useful in general:

• Intimidation
• Perception
• Animal Handling

Leveling Progression - Levels 2-12

Here is the detailed progression for the Karlach build to get you started. You can use it as a guideline because early games can be daunting and overwhelming. Later on, once you get a feel for the class, you can start picking your options.

Level 2

By this time, you should have landed on the Ravaged beach already and started exploring the initial area. You might need 1 additional encounter if you did not obtain enough XP in the Nautiloid.

Features	Description
Danger Sense​	Gives an advantage on Dexterity saving throws, helping with various surface effects and spells.
Reckless Attack​	Pretty good melee attack option, giving an easy advantage and increasing your chances of hitting

Level 3

Subclass

Overview
Berserker
Features
Frenzy​	An upgraded version of Rage. It unlocks two new attacks that can be used with your bonus action.
Frenzied Strike​	A melee attack with a bonus action
Enraged Throw​	Throw an attack with a bonus action.

Level 4

Feat

Feat	Description
Great Weapon Master: All In​	A very powerful feat, that greatly improves combat capabilities. The main problem is the penalty to attack rolls. However, this can be negated by disabling the effect or getting various bonuses. I recommend checking the Attack Roll Guide on how to maximise your hit chance.
Ability Improvement - +2 Strength	Going for +2 Strength is a safer option, as you don't have to manage attack rolls extensively. Still with Reckless Attack, I would go with Great Weapon Master: All In​ as early as possible.

Level 5

Feature	Description
Extra Attack​	This allows attacking two times instead of one, theoretically doubling the build's damage output.
Fast Movement​	An amazing feature of Barbarian, it will make it easier to get a better position for higher ground.

Level 6 - Rogue Lv 1

As mentioned in the introduction, Rogue plays a pivotal role. It reflects part of Karlach's background, but also gives "purpose" to Berserker, as the subclass really suffers with only a bonus action, which Thief will give via Fast Hands.

Class

Overview
Rogue
Features
Sneak Attack (Melee)​	This can be exploited with weapon attacks for an additional 1d6 damage once per turn. Be sure to have an advantage or attack using Hide. Later, more damage rolls are added.
Sneak Attack (Ranged)​	This can be exploited with weapon attacks for an additional 1d6 damage once per turn. Be sure to have an advantage or attack from hiding. Later, more damage rolls are added.

Abilities

To be fair, any picks are okay, but I would emphasise two:

• Sleight of Hand - if you need a dedicated lockpicker or trap disarmer
• Charisma-based - Persuasion, Deception, Intimidation, etc.

Level 7 - Rogue Lv 2

Action	Description
Cunning Action: Hide​	Bonus action hide, which the Berserker build will not care about.
Cunning Action: Dash​	Cover more distance this turn: double your movement speed.
Cunning Action: Disengage​	Retreat safely: moving won't provoke Opportunity Attacks.

Level 8 - Rogue Lv 3

Subclass

Overview
Thief
Features
Fast Hands​	Allows another bonus action, in Monk's case this will be Flurry of Blows, for more damage per turn.
Second-Story Work: Falling​	Reduces fall damage.

Level 9 - Rogue Lv 4

Feat	Description
Ability Improvement - +2 Strength	If doing the Natural Strength setup, this is my recommended pick
Great Weapon Master: All In​	If not yet taken.
Savage Attacker​	A solid feat option, which rerolls damage dice, providing a significant damage boost.
Sentinel: Vengeance​	Can be used with correct positioning to get an additional attack when a nearby ally is attacked.

Level 10 - Fighter Lv 1

Class

Overview
Fighter
Features
Second Wind​	You can use this to heal yourself in tight encounters, to get a little bit more of survivability.

Fighting Style

Style	Description
Defence​	Effective stat boost compared to other fighting style options, as a result, improving armour class.

Level 11 - Fighter Lv 2

Feature	Description
Action Surge​	The iconic action of a fighter is extremely popular for its simplicity and effectiveness. You get additional action with full bonuses from Extra Attack.

Level 12 - Fighter Lv 3

The level unlocks a subclass, which will give improved capabilities for single-target damage and conditions

Subclass

Overview
Battle Master
Features
Superiority Dice	These dice give bonus 1d8 damage, can be used 4 times, and are reset each short and long rest. Easy damage increase and improved battlefield control.

Manoeuvre

Choose 3:

Manoeuvre	Description
Precision Attack​	One of the key options to make a fighter very powerful in early games. Once you obtain the Great Weapon Master: All In​ it will be easy to drastically improve hit chance and gain the +10 damage bonus.
Disarming Attack​	Very powerful action, which allows them to disarm foes and force them to drop their weapons.
Pushing Attack​	Excellent option, for when you need to push off an enemy from a ledge, or into a difficult area like Hunger of Hadar​ or Darkness.
Trip Attack​	Only the ranged option is worthwhile, which gives infinite Prone. The build does not go too much into bow attacks, so I would give this low priority.

That's it, the build is done!

Maximizing Ability Scores

Now, as the build progression is covered, there are a few aspects and important decisions you will have to make throughout the game. These will decide your final score for abilities.

Strength - natural setup

So this ability score is quite important, and as we talked already, there are a few main ways to maximize it:

1. 16 Strength - the base from character creation.
2. Feat - Ability Improvement - +2 Strength.
3. Act 2 - Potion of Everlasting Vigour - +2 Strength.
4. Act 3 - Mirror of Loss - pick +2 Strength.

This results in 22 Strength, with a +6 modifier to attacks.

Potions, Elixirs, and Consumables

Let's take a look at what consumables you can use to further empower the build.

Potions

These have short-term effects for a few turns.

Consumable	Description
Potion of Speed	This is a very powerful potion. It gives an additional action point, which can be used to cast a spell or attack. The activation is generally by drinking using a bonus action. However, you can stack together with party members and make one member Throw​ it on the ground, giving Hastened​ to everyone.
Potion of Invisibility	It can be used in two ways - the first one is to enter combat with a Surprised​ round, causing enemies to skip their turn. Another option is to leave combat if you see that it is not going in your favour.
Potion of Animal Speaking	An easy way to get the Speak with Animals​ effect.
Terazul	Gives Hastened​ and stacks with other sources of it. This is a late-game consumable.

Coatings

These are short-term coatings, used on the weapon. Only one can be activated at a time:

Consumable	Description
Oil of Accuracy	The attack roll bonus is pretty good, which improves your chances of hitting.
Diluted Oil of Sharpness	Helps with attack and damage rolls.
Drow Poison	Can put foes Sleeping​ giving an easy way to hit with critical hits.
Karabasan's Poison	Can apply Paralysed​ on foes, giving an easy source of critical hit guarantees.

Elixirs

Unfortunately, only one Elixir can be active at a time. However, the good thing is that they last for the whole day, before making a long rest. This makes exlixirs very useful and economical.

Be sure to activate them before combat, as otherwise, you will need to use Bonus Action.

Consumable	Description
Elixir of Bloodlust	As you will be able to easily kill at least the weakest foe, this ensures additional attacks per turn. This is the strongest elixir option in most cases.
Elixir of Hill Giant Strength	Sets the strength value to 21 until the Long Rest. This is a perfect option for the early game, while you are limited to 17 Strength. Here is a farming guide for Elixir of Hill Giant Strength. You can then set the strength to 8 and put those points elsewhere.
Elixir of Cloud Giant Strength	Available later in the game, the elixir sets the strength to 27. Excellent option to be used in case, Elixir of Bloodlust is unavailable, or you have missed some of the strength boosts.
Elixir of The Colossus	Provides bonus damage of 1d4 and some other good bonuses.
Elixir of Viciousness	Reduces the requirement for critical hit rolls.
Elixir of Vigilance	For some encounters, you will want to go first. This elixir will ensure that it overcomes even surprise mechanics. However, if you have Alert,​ this becomes redundant.

Illithid Powers

This special mechanic in Baldur's Gate 3 allows you to consume tadpoles and unlock special Illithid Powers.

At first, you can only use the base powers. As you move to Act 3, you will be able to unlock the outer ring powers, also called Elite.

Illithid Power	Type	Description
Favourable Beginnings	Base	Beneficial power to take as it does not have any costs, and provides only benefits on the first hits with attack rolls.
Luck of the Far Realms​	Base	It's an easy way to ensure you land critical hits, especially good when you need an instant damage boost.
Cull the Weak​	Base	It can help to kill an enemy faster if it is left with a few HP.
Psionic Overload​	Base	It can help give a slight damage boost. The main issue is that this cannot be activated outside of combat, so you will have to use an action point.
Psionic Backlash​​	Base	Excellent way to deal additional damage with reaction, early and mid game.
Ability Drain​	Base	Decreases enemy ability score, free use, so worth getting.
Shield of Thralls​	Base	Excellent option for bonus temporary HP. It can also apply Stunned on foes after it is destroyed.
Illithid Expertise​	Elite	It can be used to maximize the effectiveness of charisma-based skills, especially those relevant to the main character.
Psionic Dominance​	Elite	It can be used to save yourself from a deadly spell.
Illithid Expertise​	Elite	It can be used to maximize the effectiveness of charisma-based skills, especially those relevant to the main character.
Psionic Dominance​	Elite	It can be used to save yourself from a deadly spell.

Equipment Recommendations

Now I would like to go through some gear recommendations to maximize the Karlach Build. Items are especially important as they take the build to the next level thanks to their unique effects.

Act 1

Slot	Item	Description
Melee (Two-Handed)	Unseen Menace	Gives a very easy advantage option, greatly increasing hit chance.
	Svartlebee's Woundseeker	One of the best early game weapons with a boost to attack rolls against enemies that have already received damage.
	Larethian's Wrath	Excellent sword, which has a powerful Razor Gale​ action, easily hitting multiple foes in its cone.
	Sword of Justice	A solid greatsword option with special shield action.
Ranged	Bow of Awareness	Gives bonus initiative, allowing one to go earlier in combat.
	Gandrel's Aspiration	Gives easy Advantage against monstrosities for all weapon attacks.
Head	Diadem of Arcane Synergy	One of the best headwear for pure weapon damage increase.
	Haste Helm	Improves movement speed, allowing one to reach important targets easily, early in the game.
Cloak	-	Nothing really of note here.
Armor	Adamantine Scale Mail	A solid armour option, with Reeling​ effect and damage reduction.
	Bloodguzzler Garb	Grants Wrath​ when being damaged by enemies.
	Githyanki Half Plate	The most relevant early-game armour, that you can take from Lae'zel
Gloves	Gloves of the Growling Underdog	Gives easy advantage on attacks, making it an easy choice to counteract the effects of Great Weapon Master: All In​ penalty to attack rolls.
	Gloves of Dexterity	One of the best picks if you are doing a Natural Strength setup. This allows for a reduction of Dexterity investment to 8, and puts other points into Constitution or Wisdom.
	Gloves of Baneful Striking	Applies the Baneful Strike​ effect, which weakens foe saving throws, making them perfect targets for control actions or spells. This can make many bosses easier, as you can now land spells with a higher chance.
Boots	Disintegrating Night Walkers	One of the best boots in the game for walking on Difficult Terrain. It also comes with Misty Step​ when you are in need of high mobility.
	Boots of Genial Striding	Excellent boots to help move through Difficult Terrain.
	Linebreaker Boots	Gives Wrath​ when using Dash. Once you have Rogue level 2, you can activate it using its special Cunning Action: Dash.
Amulet	Broodmother's Revenge	If you can acquire it, this can be the best amulet option for most of the game.
	Amulet of Branding	Excellent amulet that gives an easy vulnerability source, for the mid-game.
	Amulet of Misty Step	Gives a free Misty Step,​ which greatly improves your mobility.
Rings	Ring of Protection	Bonus armour for survivability.
	Caustic Band	Improves damage on each hit.
	Crusher's Ring	Movement speed boost, which is especially important in some big area fights in Act 1.

Act 2 - mid-game

Slot	Item	Description
Melee (Two-Handed)	Shar's Spear of Evening	Depending on your decision on Nightsong, you will obtain one of these. The Shar's Spear of Evening is considerably stronger in Act 3, when also using Bhaalist Armour.
	Selûne's Spear of Night
	Thermodynamo Axe	A decent weapon that comes with a Heat​ mechanic. Building 7 stacks allows for unleashing Heat Convergence. I would only use it when you have a chance to land Cleave, to multiply its damage; otherwise, it is not worth using.
	Halberd of Vigilance	One of the first weapons with a +2 enchantment comes with a Force damage rider.
	Drakethroat Glaive	The weapon is used to enchant other weapons with Draconic Elemental Weapon​ for different elemental damage riders.
Ranged	Darkfire Shortbow	Although not mandatory, this bow is useful as it can apply Haste​ without spell slots. Best used before combat, or continue using Act 1 weapons.
Head	-	Previous Act headwear
Cloak	Cloak of Protection	Improves survivability and Saving Throw success.
	Cloak of Elemental Absorption	Helps to absorb elemental damage, which can then improve your weapon attacks.
Armor	Dark Justiciar Half-Plate	Both of these armours are excellent choices. The evil one is slightly better as it also reflects damage, but overall, the free Shield of Faith​ is a great addition.
	Dark Justiciar Half-Plate
	Yuan-ti Scale Mail	I would only wear this if you have 16 dexterity, to make it a competitive armour.
Gloves	Thermoarcanic Gloves	Thematically, these are one of the most interesting gloves. Similar to Thermodynamo Axe it gives Heat​. You just need a fire damage rider, which you can get via Soul Coin or Drakethroat Glaive enchantment on your weapon.
	Flawed Helldusk Gloves	Solid gloves for weapon damage boost.
	Gloves of Dexterity	The gloves are an option for enabling you to run 8 Dexterity investment and maximising other abilities - strength, constitution or charisma.
Boots	Evasive Shoes	Gives +1 Armour Class, which is a significant survivability boost.
	-	Boots from Act 1 are still perfect.
Amulet	Broodmother's Revenge	Continues to be the best amulet in terms of damage boost.
	Amulet of the Harpers	Excellent pick with Shield​ spell, without using your spell slots.
	Periapt of Wound Closure	Excellent amulet that can help in tight situations when you are Downed.
Rings	Shadow-Cloaked Ring	Gives additional damage boost while the target is at least Lightly Obscured.
	Ring of Protection	Improves armour class, making it easier to avoid enemy attacks.

Act 3 - Final Build setup

Piercing Setup

If you are okay, with Karlach wearing "evil" items, you can create a very powerful setup, that destroys enemies easily with Bhaalist Armour:

Slot	Item	Description
Melee (Two-Handed)	Shar's Spear of Evening	Listed the weapons in terms of being "powerful". Shar's Spear of Evening, requires an evil decision, which is not for everyone. Nyrulna is truly great weapon, and includes special actions - Zephyr Break​ and Zephyr Flash​ which offer really good weapon actions. The last is Selûne's Spear of Night, which can kind of be good with its Moonmote​ effect, however, it is only once per long rest.
	Nyrulna
	Selûne's Spear of Night
Armor	Bhaalist Armour	One of the best armours in the game, offering Aura Of Murder​ effect to debuff enemies.

Standard Items

If you want to opt out of wearing Bhaalist Armour, or it will be used by other companions, here are all gear recommendations:

Slot	Item	Description
Melee (Two-Handed)	Nyrulna	Even if you don't use Bhaalist Armour, this weapon is great - with solid weapon actions, +3 enchantment and most importantly, looks cool.
	Balduran's Giantslayer	The best slashing-type damage two hander in the game, giving bonus damage based on the strength modifier.
	Hellfire Greataxe	Going with the fire theme, this weapon fits perfectly as it generates Heat. Sadly, its Hellflame Cleave​ does not work while in Frenzy.
Ranged	Vicious Shortbow	In terms of pure damage boost, this is the best bow, especially as you can easily guarantee critical hits via Hold Monster​/Hold Person.
	Hellrider Longbow	Gives a whooping +3 to initiative, I would only use it without the Alert​ feat.
	The Dead Shot	Reduces the critical roll requirements, giving a slight average damage boost.
Head	Diadem of Arcane Synergy	Gives Arcane Synergy​ buff, which improves damage based on the Charisma modifier.
	Horns of the Berserker	A good helmet with a flat necrotic damage rider on weapon attacks.
	Bonespike Helmet	The helmet is made for Barbarian as its main effect triggers when entering Rage​. It fits well together with Resonance Stone for double damage.
	Helldusk Helmet	Gives critical immunity and Blinded​ immunity.
	Helm of Balduran	The headwear comes with Critical hit immunity and auto-healing. This is a perfect combo with Broodmother's Revenge.
	Helmet of Grit	Allows for obtaining additional bonus action for more attacks using Great Weapon Master: Bonus Attack​ or Frenzied Strike. This requires being at 50% HP or lower, so feel free to use something like Transfuse Health​ to maintain this level. Of course, in this case, I would also recommend running Amulet of Greater Health for maximum health pool.
Cloak	Cloak of Displacement	The strongest cloak in the game, with a significant boost to defensive capabilities.
Armor	Bonespike Garb	Gives a boost in temporary HP and reflects damage to the attackers. It's a nice free bonus, especially if you have Amulet of Greater Health to maximise your Constitution.
	Armour of Agility	One of the best medium armours in the game, with a solid armour class boost.
Gloves	Gauntlets of Frost Giant Strength	If you dumped strength and used Elixir of Hill Giant Strength, this is a direct upgrade, freeing the elixir slot, and giving an easy way to maximise strength.
	Legacy of the Masters	Powerful glove option, which improves both attack rolls and damage. This helps reduce Frenzied Strain​ and Great Weapon Master: All In​ penalties.
	Helldusk Gloves	Gives 1d6 fire damage boost to all weapon attacks.
	Craterflesh Gloves	If your party has a way to guarantee critical hits via Hold Person​/Hold Monster,​ these give a huge damage boost, as they have special interaction with dice rolls.
Boots	Helldusk Boots	A straight upgrade to Disintegrating Night Walkers, as the boots also make you immune to Prone​.
	Bonespike Boots	The boots are pretty good, but the main problem is that their action, Brutal Leap​ uses Spell Save DC, which is quite low for the build.
Amulet	Broodmother's Revenge	Continues to be a powerful amulet choice for direct damage boost. You can now get something like Helm of Balduran or Ring of Regeneration to activate it automatically.
	Amulet of Greater Health	I would say this amulet is mandatory if you plan on using Helmet of Grit. It's also good as it allows you to maximise your Constitution modifier, especially for the Bonespike Garb reflect effect.
Rings	Shadow-Cloaked Ring	Gives a decent damage boost that inherits the weapon damage type. The target needs to be at least Lightly Obscured.
	Ring of Protection	A direct armour class boost.
	Eversight Ring	Allows you to see through Darkness​ if your party is running this mechanic.
	Callous Glow Ring	Although the ring is in high demand by other builds, this could be used to both improve melee weapon damage and the reflection damage from Bonespike Garb.
	Ring of Regeneration	Can be equipped to automatically activate Broodmother's Revenge in combat.

Build Mechanics and Interactions

In this section, I would like to dive deep into how to play the Karlach Build mechanics and interactions. These will help you understand what is happening and why, and maybe give you ideas on your own playstyle.

Core Mechanics and Combos

Let's go through key mechanics and tips on how to use the build effectively.

Raging as Berserker

Berserker comes with an improved version of Rage​ called Frenzy. It gives the same stat benefits and resistances. So what is the purpose? You unlock Frenzied Strike​ and Enraged Throw. The latter is best used on the Throwzerker build.

Frenzied Strike​ is what we are interested in, as the build mainly uses melee weapons. To be honest, it kinda sucks. Each hit will apply Frenzied Strain,​ reducing your hit chance, and it uses a bonus action, which competes with Great Weapon Master: Bonus Attack​.

Still, when you have a free bonus action, attacking, instead of doing nothing, is much better, as it might end the enemy. Later, once you get Thief level 3, two bonus actions make this a slightly better proposition

Managing Great Weapon Master

The most important aspect of most two-handed builds is correctly utilizing Great Weapon Master: All In​ and its -5 attack roll penalty. By putting effort into minimising the debuff, from level 4, you can get 10 flat damage boosts, making most of the enemies a cakewalk.

• Bless​ from a Cleric, Paladin, or The Whispering Promise ring for a 1d4 bonus.
• Spells like Faerie Fire, and Blindness​ give an advantage to attackers.
• Oil of Accuracy or Diluted Oil of Sharpness, for a 1 and 2 attack roll bonus.
• Gloves of the Growling Underdog - can be obtained in Goblin Camp and give an advantage for attack rolls.
• Phalar Aluve: Sing​ gives 1d4 to attack rolls.

Now, if you want more in-depth information, I have a guide covering how to increase attack rolls, which lists a lot of options and combinations. You can then pick the bonuses based on your party setup.

Soul Coins

Karlach comes with a special mechanic; she can consume Soul Coin to gain +1d4 fire damage until long rest. There are about 15-20 coins throughout the game, so to be fair, you can use them whenever you find them.

Why is this important? Well, the additional damage is always welcome, but this gives an easy source of activating Thermoarcanic Gloves and generating Heat. 

Of course, this mechanic is not a game-changer mechanic, and many people totally skip or forget it. However, it's a nice interaction specifically for Karlach, without requiring much effort or preparation from the player.

Heat Mechanic

This is a pretty simple mechanic. You accumulate stacks of Heat. This is available if you use Thermoarcanic Gloves, Thermodynamo Axe or Hellfire Greataxe. Once you have a stack, a new icon appears with the Heat Convergence​ passive. You can activate it, and it will make your next attack or spell consume the Heat​ and give increased damage. 

The trick here is to use something like Cleave​ from your weapon action to hit multiple enemies. This way, the bonus damage will apply to each hit, making the effect really powerful. Using it on one target is kind of disappointing in terms of inflicting damage.

The one downside of Heat​ is that you receive fire damage each turn. In my opinion, it's a small problem, so I would not worry too much.

Battlemaster Manoeuvres

Once you unlock Battlemaster, you can use manoeuvres to get various effects and a slight damage boost on your weapon attacks. You get a few attacks each short rest, so it should be plenty to gain a significant advantage in the combat encounter:

• Precision Attack​ - is a very powerful option, especially when you need that attack to land, for example enemy is on low HP, and killing them is essential.
• Disarming Attack​ - greatly weakens foes which rely on weapons. I would not rely too much on this against casters, but melee martials or ranged combatants will become almost harmless.
• Pushing Attack​ - can help you force enemies to specific areas, like Difficult Terrain​ or special effects of Spike Growth, Darkness, etc. You can also push enemies off the ledges.
• Trip Attack (Melee)​ can be useful if the enemy's turn has passed and you and your allies will go after that. The main problem is that this is a 1-turn Prone​ effect, meaning that they will be able to stand up on their turn, even if the movement speed is reduced. But it's still valuable as an easy Advantage source.
• Menacing Attack (Melee)​ - can be used as a way to force an enemy in place.

Build Combat loop

This section covers the main steps on how to use the build. I do recommend reading the mechanics section before, as it will give more insights into how everything works and why things are as they are.

Act 1

This covers the early parts of the game, mostly Act 1 levels 1-6:

• The build is truly simple, and the goal is to hit as much as possible.
• Rage​ and later Frenzy​ are your go-to options, especially on more difficult encounters, as they give physical damage resistance.
• The Frenzied Strike​ does compete with Great Weapon Master: Bonus Attack​ for usage. What would I recommend? Prioritise the latter, and use the former, in case Great Weapon Master: Bonus Attack​ does not activate.

Act 2

Act 2 will finally unlock Thief, with additional bonus action:

• Now you can activate Frenzy​ and use another bonus action to attack either with Frenzied Strike​ or Great Weapon Master: Bonus Attack.

Act 3

Here, Battlemaster will give some tactical opportunities on how you can approach combat:

• Action Surge​ will be a significant boost for damage each short rest. It will allow you to hit enemies 2x times with Extra Attack.
• Use various manoeuvres depending on the situation. Need to land a hit - Precision Attack. Is the enemy using weapons? Disarming Attack (Melee). Close to a ledge? Pushing Attack (Melee), and so on...

Conclusion

Thank you for reading the Karlach build for Baldur's Gate 3. This is a pretty straightforward setup for the red companion. It enables solid frontline performance and damage absorption thanks to Frenzy.

Cheers!