While the Citadel is the sturdiest of structures and the target of the enemy team, it can also provide purchaseable upgrades to improve the team. Any player may purchas upgrades by clicking on the Citadel and being in range, bringing up a window similar to purchasing a Demigod's Skills, using Gold as the currency. Upgrades are limited by War Rank, and must be purchased linearly (Can't purchase Currency II before Currency I, for example).