High School DxD, Vol. 1 (light novel) Diablos of the Old School Building

Most of Issei Hyoudou's perverted life has been filled with dreams about having a harem, so it's not a great sign when one of his dates ends with his murder! He's fortunate enough to be revived by a beautiful girl, but his luck ends after he discovers his school is filled to the brim with deadly angels and demons!