Hogwart's School for Witchcraft and Wizardry
Hair: hidden under his turban most of the time; missing at the back where Voldemort’s face is.
Eyes: one twitches.
Voice: Spoke with a stammer so he would sound pathetic, and thus, less suspicious.
Distinguishing features: pale and nervous, prone to fainting, pale, usually trembling, and then there’s that extra face…
Field: Muggle Studies, and later of Defence Against the Dark Arts (PS5, BLC).
A young wizard with a “brilliant mind,” Quirrell was a professor of Muggle Studies, and later of Defence Against the Dark Arts, at Hogwarts. In between holding these two posts he took a year off to gain experience dealing with Dark Arts; unfortunately during this time he met Voldemort in Albania, and by the time he returned to Hogwarts, he was possessed by the Dark Lord. To mask his newfound allegiance he faked a stutter and an eye twitch, hoping nobody would suspect him, though he certainly made Dumbledore suspicious.
Quirrell spent the 1991-1992 school year – Harry’s first at Hogwarts – working on an attempt to steal the Philosopher’s Stone, and thus bring Voldemort back to life. His first attempt to steal it, from Gringotts, was thwarted when Hagrid took it from the vault first and it was after this that Voldemort decided to possess him. As Voldemort’s face was sticking out the back of his head, Quirrell had to wear a purple turban the entire school year to hide him.