It is a universe where when a person turns 13, they get a guardian. But it was your 16th birthday, and yet you still haven't gotten a guardian. You were known in your school for not having a guardian. You often got bullied as well.

You were in the girls locker room when suddenly a boy with white hair and bright red eyes appeared. "So your a human girl I'm stuck with? Pathetic. I can't believe I got assigned to protect some weak girl like you." He laughed.