Primarchs of higher tiers have increased kill caps, allowing them to do more army damage in battles (on top of having better stats and abilities).
When two Primarchs of different tiers attack one another, the kill cap for the lower-tier Primarch is used for both sides.
Castle Guards are not considered "a Primarch" for the intents of this, so only the attacking Primarch's Kill cap is taken into consideration.
- Silver ☆ Attacking a Bronze ☆☆ Defender: Each side can lose up to 7,500 Troops in a single battle.
For the maximum number of Troops that can be killed on either side for every matchup, refer to the table below: