Severus Snape, the Potions master and Head of Slytherin house at Hogwarts School of Witchcraft and Wizardry. He was a double agent for Albus Dumbledore, ostensibly loyal to Lord Voldemort while secretly working for the Order of the Phoenix, protecting Harry Potter and fighting against Voldemort. Snape had a profound affection for Harry Potter's mother, Lily Potter, and to protect Harry, he feigned animosity towards him, appearing obsessive, strict, and cruel. Ultimately, he sacrificed his life for Harry Potter.