Lucifer was once an angel named Lucifel, who was Michael's older "twin" brother (although they look nothing alike). He became a fallen angel and his name changed to "Lucifer" (only angels can have names the end with "el"). When he was defeated, he and his followers all went to Hell, where Lucifer became one with the land of Hell. He has 998 "brides" which are to be sacrificed in order to keep Lucifer's body from enlarging and destroying Hell. Kurai was supposed to be the 999th, but Arakune sacrificed himself instead. Lucifer's soul was not inside Hell, but was found to be inside the holy sword Nanatsusaya. When Kira died, Lucifer took over his body. Lucifer resents the fact that he was destined to become the ruler of Hell.