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Collateral damage is an ability certain military units have which allows them to inflict damage on multiple enemy units in a defending stack. Collateral damage is often referred to by players as just "collateral". Units which inflict collateral damage include most siege units, bombers, and some naval units; these units are referred to collectively in this article as "collateral units".


When a unit with the collateral damage ability attacks a stack (that is, 2 or more enemy units in the same tile), it will face one particular defender - whichever defender is strongest against it. That attack is computed normally. But regardless of which unit wins the main battle, or how many rounds the battle goes, the attacker gets an extra damage round applied to 5-8 other defenders in the stack. The damage done is 50% of normal, so it tends to be around 10 hitpoints of damage.

Units which can inflict collateral damage have a maximum level of damage they can inflict on the attack. This collateral damage cutoff applies to all collateral attacks. If a defending unit is assigned collateral damage in the collateral portion of the attack which would lower its hitpoints below the cutoff, it only takes enough damage to drop it to the cutoff. Units which are at or below the cutoff will not be chosen for collateral damage infliction; it will go instead to some other healthier defender in the stack.

Some units also have a damage cutoff that applies to their main attack. Enemy units which are already damaged to a unit's primary attack damage cutoff cannot be attacked by it. If the main defender drops below the cutoff level during its battle with the attacking unit, the battle ends immediately; this effect is similar to withdrawal. If no defender in a stack is above a unit's primary attack damage cutoff level, then the unit cannot attack that stack.

Units with Collateral[]

The following units can inflict collateral damage. Their strength and maximum damage cutoff is also given.

Using Collateral Damage[]

Collateral damage is extremely useful if you're trying to attack a tile that's occupied by a large number of units. This situation happens most commonly when attacking a city. A good strategy when attacking a city is to first soften up the defenses with bombers, siege units, or naval units, then use siege units to attack to inflict collateral damage to the defenders remaining inside the city. Then, follow up with melee, gunpowder, mounted, ranged, or armored units, as appropriate.

The same strategy can also be used if you're trying to defend a city that's being besieged. Engage the enemy with siege units, then send your defenders on a sortie to defeat the now weakened attacking force.

Preventing Collateral Damage[]

If you're trying to survive a siege, collateral damage can severely weaken your defenders and make them very vulnerable. A partial solution is to put siege units inside your own cities, as they're immune to collateral damage from other siege units, though they tend to be rather weak at defense, so they may be better suited to inflicting collateral damage to the besiegers. If you have a belligerent neighbor, consider researching the Railroad technology as soon as possible and placing many machinegun nests inside any vulnerable city. Machine gunners aren't vulnerable to collateral damage from siege units, though they are vulnerable to bombers, so you will want to support them with SAM Infantry.