Professor Quirinus Quirrell is one of the 2 hidden main antagonists of Harry Potter and The Philosopher's Stone. He was a wizard and a Defense Against the Dark Arts teacher during Harry Potter's first year at Hogwarts. Although Severus Snape was initially thought to be the one trying to steal the Philosopher's Stone, it is ultimately revealed that the real villain is Quirrell. He was portrayed by Ian Hart, who also did the voice of Voldemort in the same film.