Professor Slatero*
Quirrell

"Poor bloke. Brilliant mind. He was fine while he was studyin' out of books but then he took a year off ter get some first hand experience..."
     -- Rubeus Hagrid

Defense Against the Dark Arts teacher 1991-1992, took 1990-1991 school year off, went to Albania to get first hand experience dealing with Dark creatures and Dark magic. Quirrell met Voldemort there, who twisted his mind to accept the Dark way. Quirrell became a host and a slave to the disembodied Voldemort. Quirrell wore a purple turban to hide the face of Voldemort which was on the back of his head. When Voldemort was defeated, he abandoned Quirrell, who died shortly thereafter.

Slatero Quirrell
*first name: according to the Internet Movie Database website's listing for the film, it's Slatero. That is not, however, considered canon until we can get it confirmed.
hair: 
eyes: 
voice: stammering
distinguishing features: nervous, prone to fainting, pale, usually trembling, and then there's that extra face...
age: young
field: Defense Against The Dark Arts
interests: