Name: Severus Snape Year: Professor House: Head of Slytherin Gender: Male Background: Severus Snape is the Potions Master at Hogwarts and head of Slytherin House. He is a tall man with greasy black, shoulder-length hair and a hooked nose. He has an unusually unpleasant personality. However, he is an expert potions brewer and he holds a position of some authority and respect under Dumbledore. His teaching style is based on intimidation and bullying. He favors students of his own house while actively undermining the efforts of students from Gryffindor. He is particularly antagonistic toward Harry, based partly on built up grudges against Harry's dad. He is also cruel to Neville Longbottom for no discernable reason except that he can sense that Neville is afraid of him. Snape is extremely sharp-tongued, and his behavior is often inexcusable, such as when he sees Hermione with her teeth expanded past her chin and says "I see no difference."
Snape was part of a group of Slytherin students in the 70s who nearly all became Death Eaters. He served Voldemort for a time, but at some point before the Potters' murder and Voldemort's downfall, turned against the Dark Lord and became a spy for Dumbledore. Snape still has the Dark Mark on his arm. He has since gone back to spy for Dumbledore again, though the remaining Death Eaters and Voldemort are not aware of this due to Snape's skill with Occlumens.