Junko Natsumizaka
Just a demonic overlord studying Earth firsthand.
He wasn't very good with magic, so two years before the Battle of Hogwarts broke out with Luna taking over, Claudia went through the same interview process with Soren that Nova went through with Stephan. McGonagall accepted Soren into the fourth year (because that's where he was at magically at the time, even if he looked older), and now he's moved onto his sixth year. Claudia used the excuse that they had tried to have Soren home-schooled for three years, hiring tutor after tutor, but none of the tutors had been able to teach him magic, so they had to resort to enrolling him in a school.