Severus Snape biography
Severus Snape is a fictional character in the Harry Potter book series written by J.K. Rowling. In the first novel, Harry Potter and the Philosopher's Stone (published as Harry Potter and the Sorcerer's Stone in the United States), he is hostile to Harry and is built up to be the primary villain until the final chapters. As the series progresses, Snape's character becomes more layered and complex, and Rowling does not fully reveal the details of his true loyalties until the end of the final book, Harry Potter and the Deathly Hallows. Snape appears in all seven novels of the series.
Over the course of the series, Snape's portrayal evolves from that of a malicious and partisan teacher, to that of a pivotal character of considerable complexity and moral ambiguity. Snape primarily teaches Potions at Hogwarts, though in the sixth novel he finally teaches Defence Against the Dark Arts, a position which he was known to have desired throughout the series. He ultimately becomes Headmaster of Hogwarts in the final novel. Rowling has described him as "a gift of a character.