Combat is decided by playing a variant of darebase called stealbase, which is similar to capture the flag. The attackers can start at any target area of a city they control or have permission to use and/or the outskirts of the region the battle is taking place in. The defenders start in the target area of the city the attackers are attempting to capture. Each city has a target area outside that is defined by the gamemaster, even if the city is inside. The attackers win if they takeover the target area of a city for 60 seconds with no opposition. Each combatant wears a flag football belt with 3 flags on it. Combatants are removed from the game if all of their football flags are taken. A set of football flags costs 1 force card. If all of a combatant's flags are removed, they must stay in the exit area of the region until the end of the battle. They are also not allowed to talk to anyone until the battle is over.
To start a battle, the offensive belligerent entity must choose a city to attack. The entity that has sovereignty over this city will automatically be the defensive belligerent entity. Up to 4 other belligerent entities may join the battle. This is on a first come, first served basis for any entity that can provide at least 1 force card or have at least 1 force card provided to them by a non-acting entity. Belligerents, besides the defensive belligerent, are allowed to oppose who they want. Any side, except the defensive side, can seize the defending city by taking over its target area. Any belligerent is allowed to attack any other belligerent, and any combatant is allowed to attack any other combatant. This includes their own forces. Other cities besides the chosen defending city can't be conquered during the battle. Separate battles must be declared to attempt conquest of other cities.
Any combatant can retreat by entering the exit area of the region, which is also defined by the gamemaster. At the end of the battle, 1 force card can be redeemed for any group of 3 flags not removed during play. After the battle, belligerent entities can mix and match surviving flags from different belts. The entity that provided the force card for the belt will be the entity that receives the force card unless they are surrendered flags. In that case, the belligerent entity will receive the force cards. To surrender, a combatant must remove the flag belt and hand it to the party they are surrendering to. However, the party being surrendered to does not need to accept the surrender and can choose to remove all remaining flags from the belt. In that case, they can't be redeemed. Any combatant that loses all of their cards from opponents physically taking them during battle or having them removed while they surrender will not be allowed to take part in any future battles for the rest of the day unless they are part of a force being attacked directly. Surrendered combatants are allowed to take part in other battles of the day unless their captors submit 1 force card to keep them detained. In that case, they can only take part on the side of an entity that is being directly attacked for the rest of the day.
Force cards can be acquired by electing to receive a force card instead of a point. Previously, the cost was 10 times as much. This rule was changed on 19AUG24, and all forces were multiplied by 10. During the City era, combat was decided by actual physical force and required no force card. From the beginning of the Eternal City era to mid October 2024, combat was decided by Chess, Chaturanga, and Stratego. Laser tag has been considered since 2011, but was ultimately decided to be less practical than the current method.