The respawn vat is at the heart of the players' fort, as it allows players to respawn if they are killed. In modes where there are aggressors to the fort, players must defend the red tank that houses the new clones, in the form of embreo-like versions of Gunner. If the Vat is destroyed, the player(s) lose the game. The four black platforms next to the vat are the players' respawn points.
In Fort Defense, Leeches will head straight towards the vat once they have spawned and only their death or the destruction of the vat will stop them from advancing any further. Walls will only slow them down, as leeches have the strength to punch through walls to get to it. It is recommended that the player builds his fort around the vat with a much protection as possible in order to keep the Vat safe, and the game going.
In Fort Wars, destroying the enemy's Vat is the goal of the game mode. Once a team's Vat has been destroyed, the game is over and the team loses.
The Vat has five health status stages:
- Full Health/Minimal Damage
- Minor Damage
- Major Damage
- Critical Damage
At stage two, the Vat will have minor leaks coming from the tank. Stage three has more leaks and an alarm begins sounding, while stage four has even more severe leaks and white smoke begins pouring from the Vat. Once the Vat is destroyed, the smoke continues to billow out of it.