The Mourning Man

Arthur Pendragon. Son of Uther Pendragon, wealthy muggle CEO of one of the world's largest investment firms. His mother Ygraine Pendragon passed away when he was little.
Oh. He's also a wizard.
Upon arriving at Hogwarts School of Witchcraft and Wizardry he begins to notice things. The castle seems so familiar, yet he knows for a fact that he's never been here before.

He also hears tell of a spirit. Not like the ghosts at the school, but more like what you hear in muggle ghost stories. the lost spirit of a man, who wanders the forbidden forest, before going to the lake and sobbing. They say he's lost someone. They call him; The Mourning Man.