Pillage other Realms for resources
Once a Realm has summoned army troops, it is able to commence a raid on any Realm belonging to a different Order. If their troops are victorious, they receive 25% of the defending realm's vault. Realms must defend their vault (with various buildings and troops) if they do not wish to have it pillaged frequently.
Raiding factors to consider
Cool Down Time
To limit bots, there is a cool down period between raids. After a successful or unsuccessful raid, the attacking army must cool down. This cool down period is at max 10 minutes and can be reduced by building more military buildings.
More Army = More food consumption
Naturally, if you are standing a large squad, your troops need to be fed. You must keep food in your storehouse at all times or else the vitality of your your troops will be capped at 50%.