Hogwarts staff of the Marauder's Map (the Weasley twins, Harry, Ron and Hermione), and Voldemort himself. He tends to favor almost sadistically harsh punishments, and gleefully allies himself with Umbridge when she prescribes such punishments on students. He has an obsessive dislike of mud, animate toys, and all other things that might interfere with his desire for an immaculately clean and orderly Hogwarts. He is also portrayed as having a constant antagonism towards Peeves the poltergeist and often tells Dumbledore that Peeves should be thrown out of Hogwarts. He also likes to wander Hogwarts corridors at night, presumably in the hope of
Hogwarts staff in "Half-Blood Prince", she becomes the acting Headmistress of Hogwarts. However, in the series finale, she does not become headmistress at the start of term as expected; Snape is appointed by the new Minister for Magic Thicknesse, who is actually under the Imperius Curse and acting for Voldemort. Death eater Alecto Carrow replaces McGonagall as deputy headmistress. Despite the many changes, she is retained as head of Gryffindor House. Before the Battle of Hogwarts, she goes to the Ravenclaw tower and finds Alecto stunned by Luna and Amycus Carrow searching for Harry. She's surprised when Amycus tells her Voldemort warned