Professor Quirinus Quirrell was a half-blood wizard who taught Muggle Studies and later Defense Against the Dark Arts at Hogwarts. During a period of time around 1991 he was possessed by the spirit of Lord Voldemort, and was killed in the summer of 1992.
 Character Development
A foolish young man I was then, full of ridiculous ideas about good and evil. Lord Voldemort showed me how wrong I was.</blockquote>
Quirrell was a Muggle Studies Professor, before taking the post of Defence Against the Dark Arts Professor. He took a year off to get some practical experience (presumably of Defence rather than Muggle Studies) where his encounters with vampires and a hag supposedly left him a nervous wreck with a stutter. However, this was an act devised to conceal his new loyalties to Lord Voldmort. He secretly worked for him from then on, his new master leading him into such crimes as breaking into Gringotts, repeatedly attempting to murder a child, and slaying a unicorn in order to drink its blood. His attempt to steal the Philosopher's Stone from Hogwarts led to his being caught by a surprised Harry. There he dropped his nervous act and revealed his true loyalties, but his failure to get the Stone and to kill Harry again before Albus Dumbledore arrived ultimately led to his death. Voldemort abandoned him just before this.
 First book
We first meet Quirrell in The Leaky Cauldron, where he is introduced by Hagrid as Harry's new teacher at Hogwarts. He has agreed to take the position as Defense Against the Dark Arts Professor, previously teaching Muggle Studies.
 Outward Appearance
Quirrell always wore a turban in order to conceal the fact that Voldemort was in the back of his head.
 Magical Accomplishments and Skills
Quirrell owned a turban which he claims was given to him by an African prince for getting rid of a troublesome zombie. It smelt of garlic and he used it to conceal Voldemort's face in the back of his head.