The concept of battalions in Fire Emblem games was introduced by Three Houses, nothing like it was present in older games. Battalions are unlocked early on, when the player completes the main storyline quest "Leading the Charge" in the second month of the Academy Phase.

Battalions are portrayed in the game as a large group of soldiers, commanded by one of your units. The main idea being that the better the character is in the Authority skill, the better of a leader they are and hence the better battalions they will be able to command. Once battalions are unlocked, you may hire and dismiss them as you please by visiting the Battalion Guildmaster in the marketplace (Explore Phase), or in the battle prepare screen.

This guide contains the following information.

Battalions provide a lot of in-battle help, the most significant of which is the ability to use a powerful Gambit attack. Damaging gambit attacks will scale off of the unit's Charm, and will always not allow the enemy to counter attack. Battalions also give combat bonuses. Typically, physically-oriented battalions will improve the commanding unit's might when attacking with a weapon, and magic-oriented battalions will improve might when attacking with spells. Battalions may also improve a unit's Hit, Crit, Avo, Prt, Rsl, and Charm.

Battalions have limited endurance. Whenever the commanding unit takes damage, the battalion will take half the damage (rounded) down to their endurance. Once a battalion's endurance reaches 0, they will retreat and stop providing any combat bonuses. Gambit will also be unavailable when a battalion retreats. Battalion endurance can be replenished by talking to the Battalion Guildmaster, or during battle preparation. Replenishing a battalion is extremely cheap, and should always be done before beginning a mission. The only case where you would not want to do this is for units taking advantage of Battalion Vantage and/or Battalion Wrath. Dimitri in particular has access to both, and is capable of infinitely critblicking enemies on enemy phase if you play carefully.

Battalion endurance damage is taken in three stages, one stage for every 1/3 of the total endurance. This is represented in game by differing colors: green is 2/3 to 3/3, yellow is 1/3 to 2/3, red is 0 to 1/3. Battalions can never go beyond the stage threshold during one round of combat. For example, if a unit has a battalion with 21/30 endurance and then takes 30 damage in combat, the battalions endurance will only drop to 20/30 and the battlion icon will change from green to yellow. Hence, it takes at least 3 rounds of combat for a battalion's endurance to be depleted.

As the commanding unit gains experience, battalions will also gain a small amount of experience. When they gain enough experience, the battalion can level up, similar to how a unit can level up. The maximum level for battalions is level 5.

Similar to units, battalions also have growth rates, however battalion growths are fixed. This means that they will always gain a set amount of stats per level up. If a stat has a decimal value, it will be rounded down in game. When battalions level up, the combat bonuses that they provide to the commanding unit will increase.

Each battalion has a movement type. Since battalions are assigned to units, their movement type must be compatible with the movement their assigned unit's class. In general, flying classes can only equip flying battalions; flying battalions cannot be equipped by any non-flying class. All other battalion movement types are available to ground classes.

These are the battalion movement types (you can search for movement types in the battalions table below).

Each battalion has a particular fighting style, which changes how they fire off gambits. For example, the Seiros Mercenaries like to charge the enemy as a group on foot. The Alliance Magic Users will shell the enemy unit in lightning by all casting spells at the same time.

Each gambit has a different target area, as well as different overall effects. Furthermore, as long as the gambit does some damage, using it will always break the shield of demonic beasts on the target tile. Other tiles hit by area-of-effect gambits will lose 1 barrier durability. It is often a good idea to launch multiple area-of-effect gambits against a demonic beast to break all shields in order to get crafting Ores.

All damaging gambits will inflict the Rattled status condition on all enemies hit. Rattled units lose all battalion bonuses, and are unable to launch gambits. Being Rattled causes the unit to lose 10% (rounded up) of their Atk, Hit, Crit, AS, Avo, Prt, and Rsl for one turn. The exact formula is below.

Gambits have limited uses. Even if a battalion still has endurance, they may not be able to fire off gambits if they already have. Replenishing battalions will also restore all gambit uses.

The game calculates a gambit's damage using the equation below. Strength and enemy protection are used for physical gambits, magic and enemy resilience are used for magic gambits.

The game calculates a gambit's hit rate using the equation below. Note that the \(5 * (Cha_{unit} - Cha_{target})\) part has a cap of 30, meaning that the hit rate will never be modified by more than 30.

Gambit damage can be further modified by the battalion's attack stat, as well as by abilities such as Death Blow. The hit rate can also be increased by abilities such as Hit +20, but the battalion's hit stat will not increase the gambit's hit rate. Gambit boosts will also affect the damage and hit rate.

A gambit boost will occur (for offensive gambits) when other allies are also in range to attack the target enemy. Gambit boosts will improve both the might and hit of the gambit, the bonuses depend on the support level between the units. As of patch 1.2.0, units will only receive the no support bonus if they can potentially support eachother.

Gambit boosts can be performed with up to 3 allies, plus an adjutant. It is unknown how the game chooses which 3 allies if there are more that are eligible. Hence, you can recieve a gambit boost with a maximum of 4 allies: three must be in range of the enemy, and an adjutant must be set. If the support level between the unit performing the gambit and the other units are all A level, then the bonuses can reach up to Might +16 and Hit +80.

Battalions are invaluable in maddening playthroughs.

Firstly, when using a gambit against an enemy, that enemy cannot counter attack. Enemies in maddening are much stronger than usual, and taking as little damage as possible during the player phase is extremely important.

Furthermore, it also freezes all enemies hit in place for a turn. This allows you to deal with large groups of enemies in little pieces, by using gambits on some enemies and defeating others. The enemies that were hit by gambits will not be able to attack your units during the enemy phase, allowing you to focus your damage on other enemies.

This table lists all the battalions in Fire Emblem: Three Houses. It shows what each battalion is called, their gambit, required authority level, and endurance. You can click into an individual battalion to see the combat bonuses and growth rates.

If you're on a smaller screen, click into each Battalion to see full details.

This table lists the location of each Battalion. Generally, you can obtain Battalions through quests, paralogues, and hiring them at the Battalion Guild. Some Battalions are only available to enemies and NPCs, and some battalions are present in the game's code but never used anywhere. Use the table filters if you want to look for a specific type.

This table lists all of the gambits in Fire Emblem: Three Houses. It displays the name of each gambit, their effect, as well as their combat stats.

If you're on a smaller screen, click into each Gambit to see full details.

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Name/AOE	Effect	Uses	Mt	Hit	Range
Absorption	Restores HP equal to 50% of the damage dealt to foes in the targeted area.	1	4	30	1
Ashes and Dust	Damages foes in the targeted area. Effective against Flying foes.	2	12	50	2–3
Assault Troop	Damages foes in the targeted area.	2	10	50	1
Assembly	Moves unit 1 tile backward and pulls foe into unit's previous space.	2	4	50	1
Bag of TricksArea of Effect unknown.	Sets Gambit Counter of all allies in the targeted area to 0. This gambit is unused in the game.	—	—	—	1
Blaze	Sets terrain in the targeted area on fire.	1	10	50	1
Blessing	Allies in the targeted area will survive one lethal attack (with 1 HP), if their HP is greater than 1 to start with.	1	—	—	1
Dance of the Goddess	Allies in the targeted area can move again.	1	—	—	1
Disturbance	Rattles foes, preventing them from moving on the next turn.	2	4	60	1
Flash-Fire Arrows	Sets terrain in the targeted area on fire. Effective against Flying foes.	2	7	50	1
Fusillade	Damages foes in the targeted area. Effective against Flying foes.	2	5	50	2–3
Group Flames	Damages foes in the targeted area.	1	2	60	1–2
Group Ice	Damages foes in the targeted area.	1	3	50	1–2
Group Lance Attack	Damages foes in the targeted area.	2	6	50	1
Group Lightning	Damages foes in the targeted area.	1	4	40	1–2
Impregnable Wall	Allies in the targeted area inflict and receive a maximum of 1 damage for the rest of the turn.	5	—	—	1
Line of Lances	Damages foes in the targeted area. Effective against Cavalry foes.	2	5	50	1
Linked Horses	Damages foes in the targeted area.	2	12	50	1
Lure	Moves foe to the opposite side of the unit.	2	4	50	1
Mad Melee	Damages foes in the targeted area.	2	4	60	1
Onslaught	Pushes foe 1 tile away.	2	8	50	1
Poison Tactic	Inflicts Poison on foes in the targeted area.	1	5	60	1
Poisoned Arrows	Inflicts Poison on foes in the targeted area. Effective against Flying foes.	2	4	60	2–3
Raging Flames	Sets certain terrain in the targeted area on fire.	2	15	50	1
Random Shot	Damages foes in the targeted area.	2	8	40	1
Recovery Roar	Cures status effects for all allies in the targeted area.	5	—	—	1
Resonant Flames	Damages foes in the targeted area.	1	6	60	1–2
Resonant Ice	Damages foes in the targeted area.	1	7	50	1–2
Resonant Lightning	Damages foes in the targeted area.	1	8	40	1–2
Resonant White Magic	Restores HP to allies in the targeted area.	3	8	—	1
Retribution	Allies in the targeted area can counter-attack regardless of range for 5 turns.	2	—	—	1
Reversal	Unit and foe switch places.	2	8	50	1
Sacred Shield	Allies in the targeted area receive 0 damage from ranged physical attacks for the rest of the turn.	5	—	—	1
Stride	Allies in the targeted area receive Movement +5 for the rest of the turn.	2	—	—	1
Wave Attack	Damages foes in the targeted area. Effective against Armoured foes.	2	13	60	1