Combat Mechanics

This article is outdated:
Some weapons' parameters, skills, perks have not been updated since 'Blazing Deserts' (2020) and 'Of Flesh and Faith' (2022) DLCs.

Tactical turn based combat is the heart of Battle Brothers. The battlefield is a hex-tiled grid, with elevation, obstacles/terrain considerations and zone of control mechanics. An Action Point (AP) system limits the number of actions (movement, skill use) a unit can take each round and an initiative-based system determines the order in which combatants act out their turns.^[1]

The character with the highest initiative will start first in a battle round, followed by characters with lower initiative. As initiative is lowered when a character builds up fatigue or has a penalty to max. fatigue (due to armor/weapons or other effects), his turn may move from first to last very quickly, if he gets fatigued too fast and the enemies do not.

Action Points (AP)

AP is spent by actions (moving, striking, using special skills/consumables, etc) and refreshed at the start of the every round. All brothers and most enemy units have 9AP. A few have less (ie Wiedergangers) and some have more (ie Direwolves, Goblin Wolfriders).

Movement on flat ground (Grass/Plains/Roads) costs 2AP. Rough terrain such as Forest/Snow have tiles that typically cost 3AP (there are tiles that still cost 2AP though (ie Light Snow)). Swamp costs 4AP for tiles with Murky Water. Changing elevation adds a further +1 to AP cost per tile. Most strikes from 1-handed weapons use 4AP (exception: Dagger (with Mastery) uses only 3AP) and strikes from 2-handed weapons use 6AP (exception: Warbrand, Rhomphaia and 2-Handed Cleavers use 4AP on regular strikes; Jagged Pike uses 5AP).

A typical battle starts with both parties in a line formation (1-2 lines deep for your forces, may be deeper for the enemy), with at least 5 hexes between parties. Human forces cannot close to melee distance within 1 round as traversing a hex takes a minimum of 2AP. Direwolves and Goblin Wolfriders on the other hand can definitely close the gap in 1 round. As bows have a range of 7 tiles on the flat (8 with mastery) and crossbows have a range of 6 tiles, both sides start the 1st round within firing distance of ranged combatants.

Fatigue疲劳

For more information, see Fatigue (attribute)

Apart from AP, all weapon strikes and movement on the battlefield also cost fatigue to execute, therefore a fully fatigued character can neither strike nor move. Every character recovers 15 fatigue at the start of his turn. As per full release version 1.1, dodging/blocking blows also increases Fatigue by 2 and getting struck by a blow increases Fatigue by 5.

Zone of Control (ZoC)

Melee units - units with a melee weapon, bare fists, or beasts (except for alps and hexes) - exert a Zone of Control on tiles directly adjacent to them. Any unit trying to leave a tile under Zone of Control will suffer automatic strikes from the hostiles controlling the ZoC (at no fatigue cost for the controlling unit). If all strikes miss, the unit leaves the tile. If any strike hits, the attempt to leave the tile fails and the unit has to try again.

A unit using any kind of ranged weapon (i.e. bow, javelins), a fleeing or stunned unit does not exert a Zone of Control. A smoke pot removes the ZoC from affected tiles for 1 turn. Footwork skill allows to move through ZoC safely. Rotation skill allows a unit to leave the ZoC by swapping positions with another non-hostile unit. Entangled, horrified, and sleeping units lose their ability to exert their ZoC.

To-Hit Chance

See also: Hit Chance

Base chance to hit (shown after selecting a skill and mousing over a target) is essentially: melee skill of brother subtracted against base melee defense of target. ^[2]

This is further modified by various factors listed below.

Gear, elevation and surround bonuses are factored in additively. (ie an attacker with Melee Skill of 70 striking a defender with Melee Defense of 0 will have 70% hit chance. If said attacker had another friendly unit adjacent/surrounding the defender, he would get +5% or in other words his hit chance would be 75% instead)
Morale bonuses/penalties and injury penalties are factored in multiplicatively (ie an archer with 86 Ranged Skill at Steady will have effectively 94 Ranged Skill at Confident (+10%))

Defense is improved by shields (mentioned below), various perks like Dodge, Shield Expert, Reach Advantage, etc. However, it is also subject to diminishing returns stat-wise at values beyond 50: each Melee Defense attribute point over 50 is halved.^[3] ^[4]

When an attack is made, a regular d100 roll happens (a procedure to get a random number in the range of 1 to 100). If the number is lower than the to-hit % chance, then this is a hit. At this point, a second d100 roll is made to see if it the attack hits the head. ^[5]

Gear

Weapons with hit bonuses include, for example, pitchforks, pikes and the Battle Standard战旗 with a +10% chance when using the "Impale穿刺" skill.
Weapon skills like Slash挥斩 (+10% hit chance, available for swords) or Thrust挺刺 (+20% hit chance, available for spears)
Shields confer strong defense bonuses which significantly lower the hit chance of anyone attacking someone who has a shield equipped. Examples of standard shields:

Buckler 小圆盾	Wooden Shield 木盾	Adarga Shield 阿达尔加盾	Kite Shield 鸢形盾	Sipar Shield 西帕尔圆盾	Heater Shield 熨斗形盾

+10 + 5	+15 +15	+15 +20	+15 +25	+18 +18	+20 +15

The Shieldwall盾墙 skill (not available to mercenaries using a Buckler小圆盾 as it is not a "normal" shield) can be used in combat to double shield defense (inclusive of Shield Expert bonus) with a additional +5 bonus for each adjacent ally also using the Shieldwall盾墙 skill. This tactic can be used to give your front rank mercenaries a big boost to defense when taking a large amount of damage is otherwise inevitable (e.g. needing to advance while under fire from enemy ranged troops).

The Knock Back击退 skill knocks the target away by 1 tile, costs 4AP, 20 Fatigue, and has a flat +25 to hit bonus. Terrain and surround bonuses apply as usual. However unlike regular strikes, Knock Back does no direct damage and its roll is not displayed in the combat log. If the game will allow you to use an ability against an enemy that is immune, it will then simply miss. This is relevant because one might assume that a pike's repel ability which both knockbacks and staggers would still apply the stagger effect to an immune enemy, it does not.

Height Level

Height levels are used as ground elevations (hills) on the battle map. When standing on them, you gain a bonus to hit chance while enemies suffer a penalty to their chance to hit you.

Changing height level costs more action points and costs more fatigue than walking on the same height layer. The Pathfinder寻路者 perk eliminates the action point penalty. The Pathfinder寻路者 perk is especially useful for polearm or 2H weapon users, as it allows them to change height level and still attack. It is also extremely useful for ranged mercenaries as they gain significant bonuses from having a higher elevation than their targets and the Pathfinder寻路者 perk facilitates easy repositioning.

There are the following types of height level in-game:

Flat Ground (0 Height Level)
1. Height Level
2. Height Level
3. Height Level

When standing on a higher height level than your opponent, you gain a +10% chance to hit and they suffer a -10% penalty to hit. It is always advantageous to have the high ground in any battle and the AI will try to occupy the high ground whenever possible, especially their ranged units.

Ranged weapons gain an additional hex of range for each level of height and improved hit chance versus targets at a lower height level.

You only count as being in melee attack range if there is a one level difference of height between opposing characters standing in adjacent hexes. If there are two or more levels of height difference between the hex a character is standing on and an enemy in an adjacent hex, you do not count as being in melee attack range or being in each other's Zone of Control.

Surrounding

Surrounding occurs when two or more units are adjacent to another one they fight against. For each unit after the first surrounding, a bonus of +5% melee hit chance is given to allies attacking the surrounded target. Both allies and enemies are affected by surrounding.^[6] Stunned眩晕 brothers or brothers with Ranged Weapons will not contribute to surround bonus.^[7] Non-hostile parties, be it Peasants, Mercenaries, Noble House Forces or alike, don't provide surround bonus for your party.

Some 一些Perks特长 can affect surrounding:

Backstabber背刺者 doubles the surrounding bonus to melee hit chance to +10%.
Underdog以少敌多 negates the surrounding bonus to melee hit chance unless completely surrounded - in that case, the bonus is +5% in total. If an attacker has the Backstabber perk, its effect is negated and the normal surrounding bonus is applied instead.

Let's study a case. A Raider is surrounded by your mercenaries Diethelm, Tostig and Erik.
It is Diethelm's turn. Attacking the Raider with his Handaxe手斧, Diethelm benefits from a bonus of +10% hit chance. That is +5% for each ally adjacent to the target after the first. With Backstabber背刺者, Diethelm would have benefited from a total bonus of +20% hit chance.
It is now the turn of Gunther, another of your mercenary. Gunther is not adjacent to the surrounded Raider and attacks him with a Longaxe长柄斧. He will also benefit from a bonus of +10% hit chance, doubled with Backstabber背刺者 for the same reasons.
Finally, your archer Bernhard acts. He attacks the same Raider with a Hunting Bow猎弓. Bernhard will not benefit from any bonus because he is using a Ranged Weapon.

Another case in picture:

NOTE: In case of friendly melee fire such as the two handed axe round swing, the enemy surround modifier works AGAINST you, which is particularly devastating against Weidergangers as they have backstabber. Meaning in the example above if the blue circled brother was to use his two tile pierce attack against the raider below, and thereby also target the brother circled in green. The chance to hit the green brother with friendly fire would likely be higher than that of hitting the enemy bandit, as the surround multiplier of nearby raiders would apply to the friendly fire attack. This is likely an oversight by the devs.

Perks特长

Dodge闪避 gives a bonus equal to 15% of current Initiative to both Melee Defense and Ranged Defense. Note that Dodge loses effectiveness due to certain injuries which affect Initiative and as a mercenary builds up fatigue during battle (accumulated fatigue lowers Initiative). Dodge is also less effective on characters that are wearing heavier types of armor and using heavy weapons (e.g. Fighting Axe) and even shields as your Initiative is lowered based on the fatigue penalty of equipped weapons, shields, armor and by what is being carried in your bags if it has a fatigue penalty (although this penalty is reduced by 50% while said items are in your bags).
Shield bonuses to Melee Defense and Ranged Defense can be increased further by using the Shield Expert盾牌精通 perk which increases the base defense bonuses of the currently equipped shield by 25%. Unique shields with higher bonuses to defense values make this perk even more potent.
Some weapon masteries increase the to-hit chance of particular attacks of the related weapon (e.g. Sword Mastery剑术精通 gives the Split劈开 and Swing挥击 attacks available when using a Greatsword巨剑 or Warbrand长刃战刀 a +5% chance to hit).
Some other perks give bonuses/maluses to hit chances under specific conditions. They are described in more detail on the Perks特长 page.

Day/Night Cycle

Battle Brothers uses a day/night cycle, going through the following phases

Dawn - Morning - Midday - Afternoon - Evening - Dusk - Night

Battles fought during the night give combatants the Nighttime夜间 debuff which gives them penalties of -2 Vision, -30% Ranged Skill and -30% Ranged Defense (if not immune to the effects - e.g. having The Fangshire獠牙乡 helmet equipped). As Ranged Skill for both AI ranged troops and human-controlled mercenaries generally tends to be significantly higher than Ranged Defense in most cases, this usually works out in favor of the defender. Thus it is advantageous to attack enemies which have ranged superiority during Nighttime.

Ranged To-Hit Chance

Ranged to-hit rolls operate in the same manner as melee to-hit rolls, where to-hit = Ranged Skill of brother subtracted by base Ranged Defense of target. A few additional factors come into play though, besides the usual gear and perk considerations, namely:

1. Distance and base accuracy bonus of strike

Regular bows suffer -4% accuracy per hex with Quickshot (no base accuracy bonus)
Regular bows suffer -2% accuracy per hex with Aimed Shot瞄准射击 (offset by a +10% base accuracy bonus)
Crossbows suffer -3% accuracy per hex when using the Shoot Bolt弩矢射击 skill (offset by +15% base accuracy bonus for the Shoot Bolt skill (only +10% base accuracy bonus if using a Spiked Impaler刺桩重弩))
The first hex from the bowman is NOT counted and does not give penalties for the purposes of to-hit chance calculations.
Examples:
(a.) Aimed Shot瞄准射击 by a Ranged Skill 50 bowman on a Bandit Thug with a Ranged Defense skill of 0 who is 7 hexes away, will have 50% + 10% (Aimed Shot) - 12% (accuracy degradation of 2 for 6 hexes of distance) = 48% to-hit chance.
(b.) Shoot Bolt弩矢射击 by a Ranged Skill 50 crossbowman on a Bandit Thug with a Ranged Defense skill of 0 who is 6 hexes away using a Light Crossbow轻弩, will have 50% + 15% chance for Shoot Bolt弩矢射击 - 15% (accuracy degradation of 3 for 5 hexes of distance) = 50% to-hit chance.
Thrown weapons (e.g. Bundle of Javelins标枪束) suffer a penalty of -10% accuracy per hex (offset by a +30% base accuracy bonus). Note that, unlike bows and crossbows, thrown weapons DO count the first hex from the attacker for distance effects on accuracy.

2. Cover庇护 (shown as "Line of fire blocked" with it's own unique icon of a shield with an arrow) reduces overall to-hit chance by 75%. This penalty can be reduced to 50% by the Bullseye鹰眼 perk. In the above example (a.), the bowman would only have a 12% to-hit chance on the Bandit Thug if he had cover (e.g he was standing behind another enemy unit or was behind one of your own units. This chance would be improved to 24% with the Bullseye鹰眼 perk making it a core pick for ranged mercenaries.

The initial roll on whether the shot hits the intended target or its 'Cover' (which could be another unit or an inanimate obstacle) is NOT shown on the battle log though as of release 1.1. The battle log ONLY displays the to-hit roll for the intended or unintended target, without factoring in Cover a second time.^[8]

Ranged attacks confer the debuff granted by the Overwhelm压制 perk to any target struck even if it is not the intended target (e.g. hit on another target due to the scatter mechanic for ranged attacks) or even by a miss on the intended target.

As with Melee Defense, the Dodge闪避 perk and shields also affect Ranged Defense, as does height advantage/disadvantage. The Anticipation预判 perk confers a bonus to Ranged Defense based on the distance from the attacker and on the base Ranged Defense of the defender. The farther the distance from the attacker, the bigger of a bonus Anticipation预判 provides to Ranged Defense. Some enemy units have access to these perks as well (e.g. Goblin Ambushers地精伏击手 have the Anticipation预判 perk).

3. Scatter is a mechanic whereby a missed ranged attack has a chance to strike an adjacent target, friendly or enemy. Because of scatter, it can be effective to fire into a block of enemy units even if your hit chance on your intended target is low for whatever reason (e.g. due to the line of fire being blocked, due to low ranged skill or due to distance). In this circumstance, you have a reasonable chance to hit something (hopefully an enemy!).

Ranged attacks via the scatter mechanic can actually strike unintended targets one hex beyond the normal maximum range of the attack in question.

Damage伤害

Main article: Damage伤害

When the target of a skill is hit (intentionally or not) it will receive damage. There are two main types of damage:

Armor damage
Hitpoints damage

Each type is rolled separately. Damage dealt and received depends on several factors including the weapon and skill used as well as perks, traits and other modifiers. Armor absorbs and reduces damage taken. This is a simplified formula for calculating armor and hitpoints damage:

armor damage = base damage * modifiers * effectiveness against armor %

1. HP damage = base damage * modifiers * ignoring armor damage % - armor * 0.1
2. if armor = 0 (destroyed), more damage is added (cannot be negative):
   + base damage * modifiers * (1 - ignoring armor damage %) - armor damage you already did
3. if critical hit, everything is multiplied by 1.5:
   HP damage = HP damage * 1.5

For example, using a Billhook钩镰 to attack an Orc Warrior兽人战士 wearing a Looted Kettle Hat (300) and a Looted Scale Armor (280). The weapon base damage is 60-90, 30% of it ignores armor for 18-27 hp damage and it has 150% effectiveness against armor for 90-135 armor damage

Orc Warrior is hit in the head (critical hit), resulting in +50% HP damage
120 is rolled on armor damage, 27 on hp damage
Looted Kettle Hat takes 120 damage. 180 armor remains.
Orc Warrior takes 27 - 18 (10% of remaining armor) = 9 * 1.5 = 13 damage to hitpoints

Secondary damage (bleeding, miasma, etc.) usually bypasses armor and deals a constant amount of damage which can be mitigated with skills like Indomitable.

Split Man劈身

Two-Handed Axes' Split Man劈身 skill has specific mechanics. The fact that it hits the head on a successful attack has mislead many players into thinking that it always does critical damage.

In fact, Split Man has a standard chance to land a critical hit. If it does, the first strike will hit the head and deal critical damage. If not, the second strike will hit the head for half damage (armor and hitpoints). The second strike always deals half damage whether it hits the body or the head. The second strike can never be a critical hit, do critical damage or benefit from skills that increase critical damage like Chop劈砍 or Brute trait.

Weapon Durability

Weapon durability is important, as when a weapon's or shield's durability reaches zero, the weapon or shield will break.

Melee weapon durability is lowered by 3 when it strikes armor that has at least 50 durability remaining; weapons are never damaged when they hit flesh (Hitpoints). Durability loss for AoE strikes is calculated separately for each individual hit (ie a Warscythe can lose 9 durability on using Reap, if 3 targets are successfully struck and all 3 hits connect with armor).
Shield durability is lowered if it is hit by Ranged weapon projectile (bolt/arrow, throwing weapon), by being hit with the Split Shield skill of a weapon (the shield damage will vary based on the weapon doing the splitting) or by randomly being hit with any melee weapon or beast attack when the attempted attack fails but doesn't miss and hits the shield instead (-1 durability for each hit, regardless of weapon).
The Shield Expert盾牌精通 Perk reduces the incoming shield damage by half (50%) to a minimum of one, while the Axe Mastery斧术精通 increases axes' Split Shield damage to shields by 50%.
Bow or Crossbow弩 durability is lowered by 2 with each shot.

Morale士气

See full article: Morale士气

Morale has six states and represents the mental condition of combatants and their effectiveness in battle. Unbreakable state is exclusive to Undead亡灵, and can not be changed. Steady is the default state, and non-undead enemies start with it and it can raise and lower as they pass or fail morale checks. Brothers' morale depends on their mood: good mood gives a chance to start with Confident morale, and bad mood lowers the maximum possible level of morale the brother can have. Some traits also affect starting morale or its maximum.

If morale drops to Fleeing, the unit cancels its active Shieldwall盾墙, Spearwall矛墙, Riposte还击架势 and Indomitable不屈, is also instantly moved to the end of turn order. At the start of a round Fleeing units have a penalty of -1000 initiative for turn order only, so they will act last, if not under Adrenaline肾上腺素. Fleeing units try to run away from enemies and can't fight or use skills, and even don't fight if surrounded. Player loses control over fleeing brothers. Fleeing units can rally on their own when not adjacent to enemies, or if targeted by skills like Rally the Troops重振士气 that restore their morale.

Morale states apply multipliers to some attributes as shown below. They count after additive bonuses from skills, perks and equipment, affecting them as well. Some states are indicated by icons.

State
Unbreakable永不动摇
Confident		1.1	1.1	1.1	1.1
Steady
Wavering	0.9	0.9	0.9	0.9	0.9
Breaking	0.8	0.8	0.8	0.8	0.8
Fleeing溃逃	0.7	0.7	0.7	0.7	0.7