Hyoudou Issei is an ordinary yet lecherous high-school student who is killed by his girlfriend, Amano Yuuma, during their first date. Yuma is revealed to be a fallen angel named Reinare who was sent on a mission to eliminate divine weapons. Issei is later reincarnated as a demon by his senpai Rias Gremory; in return, he will serve under Rias to fight against the fallen angels.