An army is a large group of soldiers that can be controlled to attack other armies or siege a holding during wars. Based on its composition an army will be shown having a certain quality.
After an army has completed half of a move order it becomes movement locked, meaning that it will not be able to receive orders until it arrives at its destination.
Armies ordered to cross a sea zone will embark onto a fleet. Embarking costs Gold proportional to the army size. While embarked army maintenance is raised by +25% and the army will start to lose supplies after 30 days at sea.
Every unit has five important stats:
- Strength: Represents how many soldiers are in the unit. Affects the total amount of stats.
- Damage: Each point causes 0.03 damage during the battle phase.
- Toughness: Reduces losses caused by damage (both routed and killed). Each point allows taking 1 damage before losing all strength.
- Pursuit: Each point causes 0.17 damage during the retreat phase.
- Screen: Each point blocks 0.33 damage during the retreat phase.
Levies are conscripted peasants that make up the bulk of all armies. They are not very impressive on their own, but are used in great numbers to complement more important troops. A Levy has 10 Damage and 10 Toughness.
Knights are characters that fight in an army. Each ruler can only have a small number of Knights. By default, Knights are appointed automatically based on their Prowess skill, but characters can be manually forced or forbidden to become Knights.
Knights combat stats are based on their Prowess skill. Each point of Prowess grants 100 Damage and 10 Toughness.
If an army loses a Battle, each Knight has a 10% chance to be captured and imprisoned and 5% chance to be killed. The chances are increased to 55.3% and 27.6% respectively if the army is defeated in the Early Battle Phase.
To be appointed as Knights, character must fulfil the following conditions:
- Is adult
- Is not imprisoned
- Has neither the Blind nor Incapable trait
- Members of the clergy and characters with the Devoted trait may only serve as knights if their faith has the Recruitment Clerical Function doctrine, the Warmonger tenet, or the Unrelenting Faith tenet.
- Based on the View on Gender doctrine:
- Male Dominated: only men may become knights
- Female Dominated: only women may become knights
- Equal: both men and women may become knights
Each army can have one Commander, a character who commands the army and uses its Martial skill to improve an army's Advantage. There are many different Commander traits available, which either have a direct effect on battles or give the Commander bonuses outside of battles.
If an army loses a Battle there is a 10% chance for its Commander to be captured and imprisoned.
Men-at-Arms are trained troops that come in several different Regiment types which excel in their given role, all with their own stats and uses. Each type of Men-at-Arms will counter at least one other type, reducing their Damage proportional to the size difference of the countering Men-at-Arms. Men-at-Arms regiments are reinforced at a rate of 10% of their maximum size per month.
Each Ruler has a limited number of Regiments for Men-at-Arms, but existing Regiments may be upgraded to increase their size. Regiments can also be downsized to lower the monthly maintenance or destroyed, but the cost is not refunded. Men-at-Arms Regiments are inherited by the primary heir when a ruler dies, but if the heir already has their own Regiments, they will not inherit more than what their limit allows.
Feudal and Clan Rulers pay for Men-at-Arms with Gold. Tribal Rulers pay twice more with Prestige.
All Men-at-Arms except Elephants triple their maintenance cost when raised.
Regular Men-at-Arms are available to all cultures as long as the other requirements are met.
Regional Men-at-Arms are made available through regional innovations.
Cultural Men-at-Arms are locked behind cultural innovations that are only available to specific cultures. They tend to be more powerful than their regular counterparts.
Siege Weapons are Regiments that cannot fight in battle, but will greatly increase Siege Progress when attacking Holdings. They are unlocked by discovering the innovation with the same name.
Supply reflects whether armies are properly provided with food and other necessities. Armies carry supplies with them as they move around the map. All armies can carry at least 100 units of Supply, although armies commanded by a commander with the Living Off the Land perk can carry up to 300 supply. When they are raised, they start with 100 Supply. Supply is consumed once per month whenever armies are in a Barony with a lower Supply Limit than the army size and gained whenever armies are in owned, occupied or allied territory up to the current Barony's Supply Limit. Low Supply will apply penalties to Advantage in battles. If an army runs out of Supply entirely, it will receive a bigger Advantage penalty and also take Attrition damage every month.
The base supply limit of a barony is 2000. The minimum supply limit of a barony is 1000. Each point of development increases a county's supply limit by +150. Coastal baronies have their supply limit increased by +25%. A barony's supply limit can also be affected by its terrain. Tribal baronies only provide half of their supply limit to armies belonging to other governments.
Attrition is a loss of Levies and Men-at-Arms that is caused by various factors:
- Besieging and looting armies suffer 1% attrition per month.
- Armies that have completely run out of supplies suffer 5% attrition per month.
- Moving into a hostile County that only borders other hostile Counties instantly causes the army to lose 5% of their troops (minimum of 100) unless the County is coastal.
Temporary modifiers, tenets and traits of an army's commander may reduce the amount of attrition taken:
|Accustomed to Foraging modifier||−10%||Any|
|Improved Pillaging modifier||−25%||Any|
|Sanctity of Nature tenet||−25%|
|Sun Worship tenet||−25%|
|Jungle Stalker commander trait||−50%||Jungle|
|Reaver commander trait||−75%||Any|
Special soldiers are maintenance free armies that belong to historical rulers and do not reinforce.