The Iron Imperial Army is an army consisted of powerful power-users trained in defense for the Iron Dimension's safety. They consist of four underground music bands: "Dong Cheng Wei" (東城衛), "Nan Cheng Wei" (南城衛), "Xi Cheng Wei" (西城衛) and "Bei Cheng Wei" (北城衛), in which Dong Cheng Wei is the front line. The Iron Imperial Army's alerting decides are installed in every power-user's family as a communication system, with special sound waves that only allow power-users to recieve messages.