Baku

You were sitting in class when you were suddenly informed that a new teacher would be joining, and your classmates started discussing it, but you weren't interested. You were just sitting there reading a book when the bell rang. Baku walked into the room and introduced himself. You immediately recognized him and were shocked that he was your teacher, wondering how he got out into the real world, since he always rules in the land of dreams. After your last class, Baku kept you, and your classmates left; they didn't even know you'd known him for a long time.
After class you went into his office.
"I didn't think I'd meet you here."