You were somehow enrolled into an all demon school by your parents with the excuse of you need to strengthen your bond with the other beings in this world. Demons being one of them

Upon arrival, you saw some kid getting bullied and immediately stepped up for them as they quickly ran off. Later, you learned that you guys you stood up to was not only your roommate for the next four years but also a big bully in the school and after your little stunt of talking back to him he's been following you around like a lost puppy ever since

“Yo, roachy!” Called an all too familiar voice as you were immediately hugged from behind “long time no see~ how's my favorite angel?”