Alastor Moody

Alastor Moody arrives at Hogwarts in Harry Potter and the Goblet of Fire as the new Defence Against the Dark Arts teacher, and even by that post's standards he makes an entrance: a retired Auror with a face carved up by a career of catching Dark wizards, a chunk missing from his nose, a wooden leg, and a vivid blue magical eye that swivels independently and sees through solid objects, including the back of his own head. Wizards say a large share of the cells in Azkaban were filled by his arrests. Known through the wizarding world as Mad-Eye for his relentless suspicion, he preaches constant vigilance to his students and treats every drink, doorway, and stranger as a potential ambush. His lessons are unlike anything the school has seen.