Best Battle Master Fighter Build - Baldur's Gate 3 (BG3)

Battle Master Build - Tactical Fighter Leader

The build is simple yet effective and plays the role of frontliner. The good thing is that this does not require any special handling and you go straight 12 levels into Fighter. At level 3 you pick Battle Master, which gives special actions called Manoeuvers.

These actions use Superiority Dies, and give you different actions to improve your combat capabilities, here are a few of them:

• Disarming Attack - targets may drop the weapon, pick it up, and leave unarmed.
• Precision Attack - add Superiority die to Attack Rolls, in case you need the attack to hit.
• Pushing Attack - push the target away and deal damage, for those ledge kills.
• Trip Attack - leave target prone, open for bonus hit chance.
• and many more

Each one of them gives a status effect that can impair or disable the enemy in combat. Another good thing is that these Superiority Dice reset each short rest, allowing these to be used in almost every combat encounter. So if this got you interested let's jump into the build

Short overview

This is a short overview and progression of the build. Use it to get a glance if you want to pick the best options without going deep into the explanations. A more detailed description with texts, suggestions, and improvements can be found in the next sections.

Starting the Game

We start with the early game. I would go into what are the best Races, Abilities, and Skills for the build. Some of these choices are impactful as you cannot respec them.

Races

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

Race	Features	Description
Half-Orc	Darkvision​ Relentless Endurance​ Savage Attacks​	A perfect Fighter race gains additional roll for critical hits, but most importantly, can stand up instead of being Downed.
Githyanki	Martial Prodigy​	Very versatile race, that unlocks special items but also gets some spells like Misty Step and Enhance Leap.
Duergar Dwarf	Dwarven Combat Training​ Superior Darkvision​ Dwarven Resilience​ Duergar Resilience​	Very solid choice, especially as they can enlarge themselves and also become invisible.
Wood Half-Elf	Civil Militia Darkvision​ Fey Ancestry Fleet of Foot - your movement speed is increased by 1.5m.	One of the more popular options, Wood Subrace gets bonuses to bonus mobility, which you will need a lot.
Wood Elf	Elven Weapon Training​ Darkvision​ Fey Ancestry Fleet of Foot - your movement speed is increased by 1.5m.	Similar to Wood Half-Elf, just longer ears.
High Half-Elf	Civil Militia Darkvision​ Fey Ancestry	I recommend this option for the main character. You could take Friends cantrip for additional luck in the dialogues. Otherwise, nothing special, and opt out for other options.

Class

The build is going into one class - Fighter. They give all weapon and armor proficiencies, making them extremely versatile front liners - two-handed weapons, swords, scimitars, dual-wielding, etc.

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

Fighters get a unique choice of different Fighting styles. They give decent bonuses to various stats, pick one based on your preference. With this build, I would recommend going with either a Sword and Shield or a Two-Handed Weapon. For Dual Wielding I would do a different setup and different attribute allocation.

Fighting Style	Description
Defence​	This works for both Sword and Shield and Two-Handed Weapons. The +1 Armour Class is a solid choice, increasing the survivability of Battle Master.
Great Weapon Fighting​	Take this to optimize damage output and ensure that low-damage rolls are re-rolled. Just remember, that this is a marginal damage improvement, and its not as impactful as it sounds.
Duelling​	This is an option that is useful for sword and shield early in the game with +2 damage. However, 8+ levels I think this falls off and instead, you could take Defence.

Background

Backgrounds are mostly for role-playing and you can pick whatever you prefer. Fighter, mainly benefits from Strength related skills, if you want some optimization there are a few options:

Abilities

Now let's take a look at the abilities of the Battle Master Fighter build. Correct allocation will allow us to maximize the early gameplay and get good modifier bonuses.

Ability	Value	Description
Strength	17 (15+2)	The main damage attribute, especially if going with two-handed weapons. High strength will also increase jumping distance and carry weight.
Dexterity	14	Early in the game, I recommend going with 14 Dexterity. You can use some good medium armor like Half Plate Armour from La'zael. Overall you can have 15-18 AC in the early game. Moreover, higher dexterity will allow you to start combat earlier.
Constitution	16 (15+1)	Important stat for frontlines to ensure that you can survive more hits, but also have successful Constitution Saving Throws.
Intelligence	8	Not an important stat for us
Wisdom	10	We get 10, to not get any negative modifier for Wisdom Saving Throws, as there are many of them.
Charisma	8	We gimp this ability as it is not relevant for Fighter Battle Master in combat. However, if you are the main character, you could put a few points here from Wisdom, to get better success in dialogues.

Skills and Expertise

Overall, the skills should be impacted by your roleplaying and background decisions. However, you would still want those that will give you the best benefits. My recommendations are one of these:

• Athletics - if you did not get it from the background
• Perception - always good to have
• Acrobatics - as you have decent dexterity this will be effective.

However, you may want some other options, especially if you are the main character

• Intimidation
• Perception

Leveling Progression

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

Level 2

At the second level already fighter gains its most popular action:

Action	Description
Action Surge​	For each short rest, you can add additional action points for bonus attacks. As you progress and obtain Extra Attack​ this will even give more than 1 additional attack.

Progressing with Elixir of Hill Giant Strength

Well, there is a trick early in Act 1, after you reach the first settlement - Druid's Grove. There you can stock up on some really powerful potions for Acts 1, 2 - Elixir of Hill Giant Strength.

What do they do? They increase the Strength to 21 until a Long rest. More or less this negates any need to have strength investment if you plan to use them till the late game. This is somewhat gimmicky, however, if you are interested here is a guide on how to farm Elixir of Hill Giant Strength.

So here is the setup once you get these Elixirs and decide to use them. Remember to respec, to get the full utility:

Ability	Value	Description
Strength	8	The potion will raise the strength to 21, meaning that we do not need this ability.
Dexterity	16 (14+2)	With the freed-up points from Strength, dexterity can be maximized for a +3 initiative bonus.
Constitution	16(15+1)	Important stat for any build gives bonus HP and improves the success of Constitution Saving Throws, which ensures your Concentration spells don't break.
Intelligence	8	Not an important stat for us
Wisdom	14	This will provide +2 bonus for Wisdom Saving Throw and Perception checks.
Charisma	12	As more abilities become free, you can increase this one.

Level 3

You get to choose the Fighter subclass which will have a huge impact. The build will be going with Battlemaster.

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.

Manoeuvres

These are unique actions of Battle Master, that will give you a unique edge in combat. The good thing is that they work together with a sneak attack, meaning you can empower your stealth attack even further. Here are my recommendations, you can choose only 3 of them.

I would recommend picking Menacing Attack and at least one other, as this way you can target different enemies with separate weaknesses.

Manoeuvres	Description
Disarming Attack	Makes the enemy waste their next turn picking up the weapon. This is not especially useful on mages, or beasts. Target the enemy's Strength
Menacing Attack	Frightens your target, disabling movement and imposing a disadvantage on ability checks and attack rolls. Targets enemy's Wisdom
Pushing Attack	Gives you an option to push away enemies from ledges all while dealing bonus damage. Target the enemy's Strength
Trip Attack	Makes the enemy Prone, opening for Advantages to other group members if attacking from close range. Target the enemy's Strength
Precision Attack	Can be useful for when you need that attack would land, specifically when a boss or particular enemy is close to death. This way you can greatly improve your chance of success.

Level 4

Level 4 brings the first feat option. There are some options that you can pick so let me give recommendations

Feat

Feat	Description
Ability Improvement	Take +2 Strength. However, if you are using Elixir of Hill Giant Strength, look for the option below. Once you stop using them change the level 4 feat to +2 Strength, this way we can easily maximize it in Act 3.
Great Weapon Master: All In​	This is the strongest feat if you are using two-handed weapons. First, it gives a bonus attack using a bonus action if you kill an enemy or land a critical hit. Second, it gives a big 10 damage boost, that comes with a -5 penalty to attack rolls. This is problematic in the early game but can be overcome in various ways. I recommend checking my guide on Attack Roll Increase, to get ideas on how to mitigate it.

Level 5

This is a huge milestone for Battle Master Fighter.

Feature	Description
Extra Attack​	This allows attacking two times instead of one, theoretically doubling the Battle Master's damage output.

The next big milestone like this will be level 11.

Level 6

And we get another Feat choice

Feats

Feat	Description
Great Weapon Master	Pick this one if you did not take it. It gives additional attack with Great Weapon Master: Bonus Attack​ and increased damage with Great Weapon Master: All In.
Alert​	This is another option if you are still using Elixir of Hill Giant Strength and have Great Weapon Master. It ensures you start most of the encounters first and cannot be surprised, making many fights easier

Level 7

The Battle Master gets substantial improvements to its subclass.

Feature	Description
Superiority Dice: 1	An additional dice is unlocked, allowing even more maneuvers per short rest.

Manoeuvres

Overall, take any of the suggested options that you skipped on level 3, but one choice is very important, especially as you will have better gear:

Manoeuvres	Description
Riposte	Allows you to attack an enemy when they miss you. This is like an additional attack not on your turn, and it does not use a reaction.

Level 8

The build unlocks the next Feat:

Feats

Overall the goal is to ensure that you have Alert​ feat at this level. Moreover, you should already be covered with Ability Improvement and Great Weapon Master.

Feat	Description
Alert​	This is the perfect time to take this feat if you did not do that before.
Ability Improvement	If you have Alert​ and are using Elixir of Cloud Giant Strength, then pick +2 Dexterity, this will prove useful for Medium Armors, which can provide you a very high Armor Class boost if you decide to use Armour of Agility.

Level 9

Besides the boost in HP, a new class feature of fighter is unlocked:

Feature	Description
Indomitable​	Greatly improves chances of succeeding in Saving Throws, minimizing the impact of crowd control actions.

Unfortunately, it is not as important for a fighter, compared to something like a Caster, which would be using a lot of Concentration spells.

Level 10

This is a major milestone for Battlemaster as one of its main features gets a big improvement

Feature	Description
Improved Combat Superiority​	Makes the Manoeuvres more potent as the additional dice roll now has a higher upper value.

Manoeuvres

By this time, pick anything that you prefer. More or less everything has been covered that is important for the build. I just suggest avoiding Sweeping Attack due to its low base roll. All other options do not bring much to the table, as they do not offer substantial crowd-control capabilities.

Level 11

This is big, very big. You gain a very important class feature from Fighter

Feature	Description
Improved Extra Attack​​	Now a third attack can be used, tripling your base damage. Especially in the late game, where you have multiple sources of additional damage, this will stack up for easy kills against most foes.

Level 12

Now the final level of the Battlemaster build is reached? How do you feel? Well, this has been a big journey, and we finish off the build with the final Feat selection.

Feat

This is the final optimization for the build, make sure that you have picked all the previous feats, as this ensures, that you can attack with bonus action, have very high strength, and go first in most of the encounters.

Feat	Description
Savage Attacker​	The final optimization of the build. This will roll damage dice two times, making it more likely that you will deal higher damage. Imagin this as and Advantage for damage rolls. This is very powerful if you have multiple sources of damage, not just base damage from the weapon.

Illithid Powers

This is a special mechanic in Baldur's Gate 3, that allows you to consume tadpoles and unlock special Illithid Powers. These range from somewhat useful, to extremely deadly. I would like to leave a few recommendations:

Base Illithid Powers

Order	Illithid Power	Description
1	Favourable Beginnings	Very useful power to take as it does not have any costs, and provides only benefits on the first hits.
2	Luck of the Far Realms	Guarantees a critical hit, a very powerful action to have.
3	Concentrated Blast	Mainly need this one for progression.
4	Cull the Weak	It allows you to deal additional psychic damage around the target you kill. Moreover, it can provide an insta-kill if the enemy is very low on HP.

Potions, Elixirs and Consumables

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

Potions

These are general consumables, and most of them are activated for a few turns. Potions are separate from Elixirs and can be active together.

Consumable	Description
Potion of Speed	In case you or your other casters have a Concentration spell slot taken and cannot cast Haste, use this potion. It acts similarly, but the effect is just for 3 turns.
Potion of Animal Speaking	A good potion to drink for role-playing and additional dialogue options with animals.
Potion of Invisibility	Can be used to get a perfect position before the encounter starts.
Potion of Flying	Gives bonus mobility for the encounters.

Elixirs

Unfortunately, only one Elixir can be active at a time. However, the good thing is that they last until a long rest, making them 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. Moreover, in the late game, with a high critical chance and good gear, this is the optimal choice.
Elixir of Hill Giant Strength	Sets strength value to 21 until the Long Rest. With this option, you can easily gimp on strength in the early game. You can put those points in Dexterity or Strength. Here is a farming guide for Elixir of Hill Giant Strength
Elixir of Cloud Giant Strength	An upgraded version that is available mostly in Act 3 via crafting. Sets strength to 27, the highest value possible.

General Tips

Now I would like to cover some general tips on how to play Battlemaster build.

Using Manoeuvers

This is the main selling point and feature of the Battle Master Subclass. The good thing is that you can use them without reservations as you reset Superiority Dice each Short Rest.

For example, use Trip Attack to make the enemy prone on the first attack. This then leaves them lying on the ground, guaranteeing constant advantage. Follow up with attacks from yourself and your allies.

However, you should not use them blindly. Always evaluate what Saving Throw the action targets, and whether the enemy will succeed against it or not. This way you can impose significant crowd control and damage on the foes.

Multiple respecs

The Battlemaster can be respecced multiple times throughout your playthrough, this all depends on the itemization. For example Act 1:

• Elixir of Hill Giant Strength - makes you not need strength investment, and get higher Constitution or Dexterity for better combat.
• Gloves of Dexterity - you can gimp on Dexterity while wearing this, respeccing and leaving it at 8 points.

As you progress you will also get other items in Act 3:

• Gauntlets of Frost Giant Strength - makes Strength 23, allowing to gimp on strength
• Amulet of Greater Health - maximizes Constitution to 23, allowing to skip any investment into this ability.
• Elixir of Cloud Giant Strength - the improved version of the previous elixir that sets Strength to 27.

So as you can see, based on the gear you equip you can then put ability points elsewhere. I would keep this priority:

1. Strength
2. Constitution
3. Dexterity
4. Wisdom
5. Charisma
6. Intelligence

This way you will know where to best allocate points while wearing or using one of the listed items. However, for the late game, I think it's best to minimize the use of these items, as you can get other options that directly improve your damage.

Two-handed vs. One-handed with Shield

One decision you will have to make is what weapons you use. Overall, in early and mid-game, I would say Two-Handed choices are much more powerful. However, in Act 3. Some items are truly powerful like - Nyrulna (can be used as one-handed or two-handed), Belm, etc. These can deal a decent amount of damage.

Another thing is that shields have an edge on Armour Class, making you feel very safe in the frontlines, standing in the enemy's face. Overall, pick what is cooler for you.

Bonus Ability points through Playthrough

During your playthrough you will have two major points in the game, where you can increase the ability points in this case - Charisma:

1. Act 1 - Auntie Ethel Hair, by sparing her life and getting her hair. This can be used to increase Strength by 1. This is the reason why we leave it at 17 so that in Act 1 we could have it at 18 (or 20 with Ability Improvement Feat)
2. Potion of Everlasting Vigour - obtained in Act 2, in Moonrise towers, after offering Astarion's blood to the researcher. This gives +2 Strength.
3. Mirror of Loss. This also provides bonus ability points based on your decisions. It gives +2 to Strength.

With all of these in Act 3, you will reach 24, the maximum value of Strength, gaining a +7 Proficiency bonus to many of the rolls.

Have an ally with Phalar Aluve equipped

Currently, this sword provides one of the most powerful buffs in the game. Although it is fixed on Honour Mode, it is still very powerful for classes that do multiple hits. As you can guess I am talking about Phalar Aluve: Shriek.

This decreases enemy Saving Throw rolls of Charisma, Intelligence, and Wisdom. But more importantly, each hit that you or your ally does adds a bonus 1d4 Thunder damage. So multiple attacks that you do, will stack up quite neatly against enemies.

Managing Great Weapon Master

One of the more important feats of the build is Great Weapon Master: All In. It gives a flat damage boost at the cost of decreased attack rolls. Generally, it is best to take this later in the game at level 8+, when you have higher attack bonuses and better gear.

However, if you can effectively use it at level 4, you will be able to easily kill most of the enemies you encounter, especially as it is easy to die in Act 1. So if you are up for putting in additional effort the benefits are immense. Here are the main ways to increase your attack rolls:

• Bless​ from Cleric or Paladin, for a 1d4 bonus.
• Spells like Faerie Fire, and Blindness​ give an advantage to attackers.
• Oil of Accuracy or Diluted Oil of Sharpness, for 1 and 2 attack roll bonus.
• Gloves of the Growling Underdog - can be obtained in Goblin Camp, and gives an advantage for attack rolls.
• Svartlebee's Woundseeker - early game greatsword that you can get before engaging in any of the major battles of Act 1.

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.

Equipment Recommendations

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

Act 1

The early game can be hard, as you do not know where to find items. You also should make a decision, about what kind of setup you are going with - Two-Handed or One-Handed.

Slot	Item	Description
Melee (One - Handed)	Blood of Lathander	The best one-handed weapon option in Acts 1 and 2. Gives +3 Enchantment and very powerful Sunbeam action.
	Larethian's Wrath	This weapon is also a contender for best one-handed weapon in Act 1, as it has a unique Razor Gale effect, allowing it to hit multiple targets.
	Phalar Aluve	A perfect one-handed option. Its special Shriek ability will also give a huge boost to other party members. However, I would better use this with Cleric as the activation costs an action and the result is two lost attacks.
	Sword of Screams	A solid weapon, that gives a bonus 1d4 psychic damage each hit.
Melee (Two-Handed)	Soulbreaker Greatsword	This weapon is mostly useful if you are playing as Githyanki as they gain additional 1d4 psychic damage. Of course, the weapon is good by itself as it gives Soulbreaker action and higher initiative.
	Unseen Menace	Solid choice as it increases the critical chance and provides an advantage on attack rolls.
	Sword of Justice	A very good choice, has +1 Enchantment but most importantly it can use a spell that gives +2 Armour Class. Fighters don't use the Concentration slot for anything else, so the Tyr's Protection is the perfect choice.
	Everburn Blade	This sword is worth it until you reach Druid's Grove, there it is much better to buy items with +1 Enchantment like Greataxe +1 or Greatsword +1 as they give a better chance of landing attacks and minimal damage decrease.
Ranged	Titanstring Bow	The best option in terms of damage. It is relevant to most of the game for Battlemaster. However, I would not rely heavily on this as you are the most powerful while using Melee weapons.
	Bow of Awareness	The higher initiative bonus will allow you to start your turn earlier.
	Hand Crossbow +1	Equipping two of these will allow you to attack with off-hand. This is important as you may not have use for Bonus Action. However, for dedicated ranged weapons check the options above. And it becomes useless once you get Great Weapon Master.
Shield	Adamantine Shield	It provides a substantial defensive boost by reducing critical hit damage.
	Safeguard Shield	Gives a bonus to saving throws, easily accessible early in the game.
Head	Grymskull Helm	Gives resistance to critical hits and allows the use of Hunter's Mark, for additional single-target damage.
	Holy Lance Helm	Great helmet, that can deal bonus damage to attacking targets. Be sure to have a high Armour Class to avoid enemy hits
	Haste Helm	Provides increased speed at the start of the combat.
Cloak	The Deathstalker Mantle	The only option in Act 1 that is okay, by providing once-per-turn invisibility.
Armor	Adamantine Splint Armour	Very powerful armor in Act 1, that is perfect for frontliner and if you have 12 Dexterity or lower.
	Adamantine Scale Mail	Another powerful armour from Grymforge, that is best worn with 14 Dexterity, to get Bonus Armour Class, making it equal to Heavy Armour.
	Githyanki Half Plate	This can be equipped when starting the game by taking it from Lae'zel. Very solid option with a high Armour Class.
Gloves	Gloves of Dexterity	These gloves set your Dexterity to 18, allowing you to respec and dump it to 8. You can then maximize Constitution and other abilities like Wisdom, and Charisma to work better against spells.
	Gloves of the Growling Underdog	Truly the best option in Act 1, as this will guarantee that your attacks land.
Boots	Disintegrating Night Walkers	Avoids slipping on various terrains and most importantly unlocks Misty Step each short rest.
	Boots of Striding	Gives additional protection against being Prone.
Amulet	Broodmother's Revenge	This is a very powerful amulet, that will lead you through most of the game, the 1d6 bonus damage is very good.
Rings	Caustic Band	Provides 2 damage increase on each weapon hit, making it a good choice in the Act 1.
	Ring of Protection	Gives defensive bonuses to Armour Class and Saving Throws.
	Ring of Absolute Force	Bonus thunder damage to thunder spells.

Act 2 - mid-game

This is the mid-game, where most of the areas will be covered by dark. Radiant equipment will shine here and having Darkvision​ is recommended. We also can get some great items, albeit some will stay the same from Act 1.

Slot	Item	Description
Melee (One - Handed)	Blood of Lathander	This still plays a major role in Act 2, even more so as its light effect helps with combat in the Darkness.
	Myrkulite Scourge	Deals bonus necrotic damage.
Melee (Two-Handed)	Shar's Spear of Evening	A late Act 2 weapon, that deals a lot of damage, and has a unique Darkness effect. It also deals 1d6 bonus damage to obscured targets.
	Moonlight Glaive	Has a passive light effect, making it effective with Callous Glow Ring. Moreover, it gets bonus radiant damage and unique attack actions.
	Halberd of Vigilance	A good choice for Act 2 and can be used till Act 3. Besides its unique benefits, it comes with bonus 1d4 force damage and not many enemies can resist it.
	Drakethroat Glaive	You can imbue a weapon with any element 1d4 damage and gain a +1 to attack rolls. You can get the bonus elemental damage on any weapon. For example, drop another weapon on the ground, cast the spell with this glaive, and equip the said weapon. This is a very powerful combo, although it may be a bug.
Ranged	Titanstring Bow	The best option in terms of damage, is through most of the game for Battlemaster. However, I would not rely heavily on this as you are the most powerful while using Melee weapons.
	Bow of Awareness	The higher initiative bonus will allow you to start your turn earlier.
Shield	Sentinel Shield	The shield provides a bonus initiative that is good for starting the turns earlier.
	Adamantine Shield	The shield is still relevant especially as it gives resistance to Critical hits.
Head	Dark Justiciar Helmet	It increases the critical chance by 5%, and it only requires you to be obscured. Moreover, gives some resistance against spells by providing bonus Saving Throws.
	Covert Cowl	Provides bonus critical chance while obscured.
Cloak	Cloak of Protection	Improves survivability and Saving Throw success.
	Fleshmelter Cloak	Reflect 1d4 acid damage if somebody hits you in melee range.
Armor	Yuan-ti Scale Mail	This armor is strange and very useful for the build. With it, you are not limited to a +2 Armour Class bonus from Dexterity. So while using it, I recommend respeccing, so that you would have 16 Dexterity. You can lower Constitution to 14 for this as you do not need it for spell concentration. Another benefit is its initiative bonus, allowing you to go earlier in combat.
	Adamantine Splint Armour	The armor is still potent in Act 2, but be on the lookout for others with 19 Armour Class like Splint Armour +2.
	Adamantine Scale Mail	Still plays a good role in Act 2, as its 16 Armour Class is plenty.
Gloves	Gloves of the Automaton	Similar to the option below, these provide an Advantage on attacks but require Bonus Action to activate the effect.
	Gloves of the Growling Underdog	These gloves are mandatory at least until you get Risky Ring or if you do not use Great Weapon Master feat yet.
	Flawed Helldusk Gloves	Provides bonus fire damage, however, only use it once you get Risky Ring.
	Dark Justiciar Gauntlets	A solid option as it gives a bonus 1d4 necrotic damage. But only use it after you get Risky Ring.
Boots	Evasive Shoes	Bonus armour class for higher survivability.
	Disintegrating Night Walkers	The boots are still a good option in Act 2.
Amulet	Broodmother's Revenge	Still the best amulet as it provides a substantial damage boost if healed - a cleric can do this easily.
Rings	Killer's Sweetheart	Allows dealing guaranteed critical hit per long rest. After this, you can just unequip it. Moreover, it can change an attack that misses and turns it into critical.
	Risky Ring	Provides an Advantage on attack rolls. This is a mandatory ring as it will both guarantee more hits and a higher chance of critical hits.
	Callous Glow Ring	Easily get bonus damage if creatures are illuminated, this can be done by casting Light on yourself by an ally.
	Ring of Free Action	Makes you immune to difficult terrain, and you cannot be paralyzed otherwise.
	Eversight Ring	Makes you immune to being blinded, which can be detrimental in some encounters.

Act 3 - Final Build setup

This is the last act of the game, where you will get access to the most powerful items. To get them as early as possible you will need some planning, but overall, it should not be a problem.

Act 3 gives so many different items, that the build can be changed multiple times as you explore it. For example you could go with Nyrulna + Bhaalist Armour for very strong damage, but sacrificing armour class.

On the other hand, you can pick Balduran's Giantslayer and take armor like Helldusk Armour or Armour of Persistence to play a more survivability role. So definitely try out different combinations to find the sweet spot for your playstyle.

Slot	Item	Description
Melee (One - Handed)	Nyrulna (BiS)	Although this would technically be a weapon used for Throwing builds, it is perfect as a melee choice. You can still throw it for AOE lightning damage as Extra Attack​ still works. It is also ridiculously powerful if you equip Bhaalist Armour for constant vulnerability.
	Belm	What makes this one special is that it has a unique Whirlwind attack, that can target all nearby enemies with separate attack rolls. You can easily do three smites on different targets with it. It has another effect when worn in an offhand, you can use it as a bonus action attack which replicates the main hand weapon.
	Duellist's Prerogative	Although the weapon is aimed at single-wielding without a shield, it is still useful as it allows additional attack using bonus action.
	Devotee's Mace	Deals 1d8 bonus radiant damage and has +3 enchantment to damage and attack rolls.
Melee (Two-Handed)	Balduran's Giantslayer (BiS)	The best two-handed sword in the game. Gives huge damage bonuses from high strength and is a perfect large monster killer.
	Nyrulna	This weapon can also be used as two-handed, albeit its base damage is not as high. It can be best in slot weapon if you use Bhaalist Armour for constant vulnerability. Otherwise, go for the above one.
	Silver Sword of the Astral Plane	A good choice, specifically for Githyanki due to bonus damage and resistance. Otherwise, it falls short of other options.
	Shar's Spear of Evening	A strong contender for Act 3. The unique Darkness effects make it an easy way to get an advantage and make enemies blind. Enemy attacks will also have problems reaching you. You can double its damage with Bhaalist Armour.
	Hellbeard Halberd	This gives a bonus of 6 poison damage per hit, which is very high.
Ranged	The Dead Shot (BiS)	The best bow for crit fishing builds as it increases the critical chance.
Shield	Viconia's Walking Fortress (BiS)	The strongest shield in the game. Has a special shield bash reaction that deals force damage. Moreover, gives good resistance to spells.
	Swires' Sledboard	Provides Force Conduit each turn, decreasing the damage that the wielder receives.
Head	Helm of Balduran	Optimal choice to ensure high survivability. Gives various bonuses and makes you immune to stuns and criticals.
	Mask of Soul Perception (BiS)	The best helmet to increase attack chance success when using Great Weapon Master: All In.
	Horns of the Berserker	Increases attack rolls and provides a bit more damage with weapons. just be sure to not have your HP at maximum, make an ally hit you before the combat.
Cloak	Cloak of Displacement (BiS)	Improves the chances of attacks missing the wearer until getting hit for that turn.
Armor	Helldusk Armour (BiS)	This armor has the highest Armour Class in the game. Moreover, it grants flying and burns enemies in flames when they attack you.
	Bhaalist Armour	This is light armor, so you should be maximizing your Dexterity and have it at least at 16, to get a high Armour Class. Together with Nyrulna you can deal frightening amounts of damage due to the Aura Of Murder​ effect. However, this requires some special in-game decisions to obtain this armor.
	Armour of Persistence	A solid defensive choice, that comes with damage reduction cantrip effects.
	Armour of Agility	The armor does not limit the Dexterity bonus to AC. So you can again make sure via respec that it is 16, to get +3 to AC.
Gloves	Helldusk Gloves (BiS)	Gives a solid bonus of 1d6 fire damage on hit, and provides a fire spell with Strength as a casting ability!
	Legacy of the Masters	+ 2 bonuses to damage and attack rolls. Which is perfect when using Great Weapon Master: All In.
	Gauntlets of the Warmaster	Battle Master-specific gloves, that give an enemy disadvantage against your Maneouvres.
Boots	Helldusk Boots (BiS)	Allows avaoiding failed Saving Throws, and uses reaction to change the outcome. Moreover, provides bonus actions for mobility and damage.
	Boots of Persistence	Gives a huge boost to mobility and avoids difficult terrain.
Amulet	Broodmother's Revenge (BiS)	The amulet still pulls strong even in the late game.
	Amulet of Greater Health	Makes any kind of Constitution ability investment redundant as it maximizes it to 23 points. However, this means that you also sacrifice an amulet slot for something that could be more offensive.
Rings	Risky Ring (BiS)	Provides an Advantage on attack rolls. This is a mandatory ring as it will both guarantee more hits and a higher chance of critical hits.
	Killer's Sweetheart	Guarantees a critical hit once per Long rest. Moreover, it can change an attack that misses and turns it into critical.

Conclusion

Thank you for reading the Battle Master Fighter build for Baldur's Gate 3. This is a very solid frontliner build that represents a commander on the battlefield. The special actions called Manoeuvres, give an edge in battle either by support or Crowd Control. Moreover, Battle Master is an effective combatant with good itemization that I cover in deep detail.

Cheers!