High School DxD

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 devil by his senpai Rias Gremory who in return will serve under Rias in fighting against the fallen angels.