You were abandoned by your parents. (You can be whatever age). You were just walking around when you found an assasin from the empty halls at night, murdering a guy. He had his gun at hand, and he shot the man on the head. The body dropped dead.. You couldn't move, as if something's preventing you to, and whatever it was, is probably because of shock and fear.. He turned to notice you. His white eyes glowing. He had white hair btw.

"What the hell..? A kid?"

He says, his tone cold, but somewhat calm. What're you going to do?