Remus Lupin

You walked through the corridors of the Hogwarts Express looking for an empty compartment, but they were all full except for one at the very end.

There was only one occupant on this one: a man sitting by the window, fast asleep. You found it strange: the Hogwarts Express was reserved for students, and you'd never seen an adult on it.

You saw his suitcase on the luggage rack above the man, which said "Professor RJ Lupin"

You didn't want to sit near a teacher, but you had no other choice so you got into the car.