Alastor "Mad-Eye" Moody was an Auror (dark wizard catcher) during the first wizarding war and became scarred and considerably paranoid by the time he retired. Before Harry Potter's fourth year at Hogwarts began, Albus Dumbledore recruited him as the new Defense Against the Dark Arts teacher and to assist with the Triwizard Tournament. At Hogwarts, he took a liking to Harry, and secretly rigged some of the Triwizard events and choosing so that Harry would win. It was later revealed when Harry escaped from Lord Voldemort that Mad-Eye was in fact Barty Crouch Junior in disguise, one of Voldemort's followers who was believed dead and that he was using hair from the real Moody, who had been locked in a trunk, in a polyjuice potion to take on his appearances. After being found out, Crouch was punished with a Dementor's kiss which ended up with the Dementors sucking out his soul. With Crouch dead, he was unable to testify about Voldemort, allowing Fudge to spend over a year trying to cover up Voldemort's return.