Student or Learner
Thorne was the last name of the woman whose spell had made Alice a demon. Who had, inadvertently I guess, made me a demon. There was no doubt in my mind that Alice had been one of those girls sent here during the Blitz, and that Thorne Abbey was where everything had started.
Who made Sophie (inadvertently) a demon? Alice or the other woman?
Not a teacher. It is ambiguous. I'd keep reading to find out. If I had to guess, I'd guess this Thorne person.