Harry Potter has a lot on his plate. About to start his third year at Hogwarts, a mass murderer escaped the Wizarding prison, Azkaban, then Dementors surrounding the school and to top everything off, he has to deal with the taunts of his classmates. Plus there's a new student starting third year as well. Who is he? And can he be trusted? AU. Merlin/Arthur SLASH. Don't like don't read. Spoilers for the first 3 books and Fantastic Beasts and all 5 seasons of Merlin