High School DXD, Vol. 8 (Light Novel): A Demon's Work (novel)
Issei is a novice devil, an idiot, and a pervert. As part of his nighttime demon-work, he heads around town, fulfilling customers’ wishes. He’s handled a few unusual requests already, but he never anticipated that his latest client would be a female college student decked out in armor! Could this be the prelude to another big upset for the Gremory Familia?