Yuuto Takamine is a normal high school boy who lives with his not-blood-related sister, Kaori Takamine. Yuuto notes that he has the devil's luck, as he narrowly evaded death from the plane crash by taking an earlier plane. He wields the fourth rank eternity sword, "Desire", who tries to constantly control Yuuto, giving him massive headaches and even compelled his wielder into killing off the other allied spirits.