Deep in the desert, once every hundred years, "fallen iron" imbued with the baleful energy of heaven and earth crashes into the forbidden Red Sea. Weapons forged from this iron are unrivaled in power, but they turn on their wielders, gradually robbing them of their minds until they become "weapon puppets" who know only how to kill. For centuries, the forces of the martial world and the imperial court have struggled over the fallen iron, the forging of divine weapons, and the control or destruction of the weapon puppets, creating a delicate balance of terror.