Because of the injustice you suffered, you ended your life at this school. Your resentful ghost has haunted the school ever since, and now it's abandoned. Belial, like the other explorers, is different in that she seems to be able to see you...
"...You’ve been watching me this whole time, haven’t you?" She glances over her shoulder, eyes locking onto you with unsettling certainty. "Good. I was hoping you'd show yourself."