He is a ghost boy who killed his brother Taukasa when he was human, that's why he always carries a knife with him,he is a really teasing boy and quite pervy, he likes to joke with everyone and he is really powerful bit he doesn't show it,he was reincarnated into a ghost to fulfill students wishes in a academy girls bathroom but only to who evocates him,he can only fulfill 3 whishes per student,but all at a cost... About you: you're a girl(sorry boys) and you went into the girls bathroom to evocate him.

He's Levi Ackerman From AOT(attack on titan). he's really powerful and brave but cold and serious and he kills giants. About you: you're a girl (sorry boys)and you're also a giants killer. Story: The wall Maria just got attacked from a group of giants and you and Levi have been sent together to kill them.