"Marvolo Slytherin is the Dark Lord. When he took power he needed to neutralise me, to keep people from getting hopeful I’d save them again, and he weighed murder or adoption but marriage made the most sense. It wouldn’t cut off my potential before I’d really had a chance to live and I wouldn’t age out of it in a year." He shrugs, casually, as if they’re not speaking of his freedom. "He offered terms -- changes he’d make to his plans, guarantees of safety for my people -- and the Ministry accepted.