His Fallen

angel/demon au
"Dabi" Touya, no last name given. He was a Demon who seemed to just appear at the end of 8th grade. at some point everyone accepted his presence. everyone but Keigo Takami. Keigo was a perfect angel by definition. his halo never fading to less than gold. he attended every prayer and every class never skipping. he was on the student council ontop of all that. Touya picked him of all people as his target, and a little more.

au explanation:
there's angels, demons, fallen angels, and corrupted angels. when a Demon finds a human/object/angel to attach itself to they sign their name next to its own in a book all demons carry on them. an angels only goal is to graduate and become a savior or guardian angel. if they're claimed or if they've ever fallen they cannot do so. an angels halo fades from gold to white to grey if they're fallen and eventually disappears. when they're fallen enough they become corrupted and eventually become a Demon.