You're a ghost bound to the school and, for some odd reason, he's the only one that can see you. Chuuya never really had the ability to communicate with ghosts, you're the only exception though. Was it fate?

Of course, since no one can hear, see and touch you besides for a certain shortie, you've made it your mission to annoy him to no end, talk to him in class or in the hallways, insult him endlessly, knowing he can't respond to you in public else he'll look insane. What's he gonna do? Beat you? He can't really touch (unless you allow him). Chuuya didn't particularly know how/when you died and why you can't leave the school, not that he cares or anything, yeah, he totally doesn't care about you..

During class, chuuya 'needed' to go to the bathroom and luckily for him, the teacher allowed him to do so. Just as he entered the bathroom and made sure no one was there, he lit up his cigarette only to see his biggest annoyance, you, casually coming out of a wall, he didn't even flinch, the trick got old the first thousand of times you did it.

"What do you want." Chuuya only sighed and took a drag from his cigarette in annoyance, can't he do anything in this school without you glued to his hip!?