Severus Snape was the Potions Master, Head of Slytherin House, Defence Against the Dark Arts professor, and eventually Headmaster of Hogwarts School of Witchcraft and Wizardry. A character of profound complexity and moral ambiguity, his true allegiance remained a central mystery for much of the series. Though he initially served Lord Voldemort as a Death Eater, he spent the majority of his adult life as a double agent for Albus Dumbledore and the Order of the Phoenix. His actions were driven by a deep, unrequited, and lifelong love for Lily Evans, Harry Potter's mother, making him one of the most pivotal and tragic figures in the Second Wizarding War.
Early Life and Hogwarts Years Severus Snape was born to Eileen Prince, a pure-blood witch, and Tobias Snape, a Muggle, making him a half-blood wizard. He grew up in a derelict Muggle street called Spinner's End in Cokeworth. As a child, he met and befriended Lily Evans, eagerly informing her of her magical nature. They attended Hogwarts together, but while Lily was sorted into Gryffindor, Snape was placed in Slytherin. At Hogwarts, Snape proved to be a prodigiously talented student, particularly in Potions and the Dark Arts. He experimented with and invented new spells, such as Sectumsempra and Levicorpus, recording his findings in his copy of the Advanced Potion-Making textbook under the moniker “The Half-Blood Prince”. He developed a bitter rivalry with James Potter and the Marauders, who frequently bullied him. His fascination with the Dark Arts and association with aspiring Death Eaters strained his friendship with Lily, which he ultimately destroyed by calling her a “Mudblood” in a moment of humiliation. The Wizarding Wars and Professorship After graduating, Snape joined the Death Eaters. He overheard a portion of the prophecy made by Sybill Trelawney concerning Lord Voldemort and a child born at the end of July. He relayed this information to Voldemort, who interpreted it as referring to the son of Lily Evans and James Potter. Horrified that he had marked Lily for death, Snape sought out Albus Dumbledore, begging him to protect the Potters. In exchange, Snape became Dumbledore's spy within the Death Eater ranks. Following Lily's death, a grief-stricken Snape dedicated his life to protecting her son, Harry Potter, though he concealed his motives behind a facade of bitterness and resentment. Dumbledore secured him the post of Potions Master at Hogwarts, where he became known for his strict, biased, and often cruel teaching style, showing open favouritism to Slytherin house and particular disdain for Harry. Throughout Harry's time at Hogwarts, Snape consistently played a duplicitous role. In Harry's first year, he secretly worked to protect the Philosopher's Stone from Professor Quirrell. During the Second Wizarding War, he rejoined the Order of the Phoenix as a re-activated spy and taught Harry Occlumency to defend his mind from Voldemort. In Harry's sixth year, Snape made an Unbreakable Vow with Narcissa Malfoy to protect her son, Draco Malfoy, and fulfill his task if he failed. This culminated in Snape killing Albus Dumbledore at the top of the Astronomy Tower, an act secretly pre-arranged with Dumbledore himself. Final Year and Death Following Dumbledore's death, Snape became the Headmaster of a Hogwarts under Death Eater control. While outwardly serving Voldemort, he covertly protected the students and assisted the resistance. He used his doe Patronus to guide Harry Potter to the Sword of Gryffindor, a key instrument in destroying Voldemort's Horcruxes. In the final hours of the Battle of Hogwarts, Voldemort mistakenly concluded that Snape was the master of the Elder Wand. To claim the wand's allegiance for himself, Voldemort ordered his snake, Nagini, to kill Snape. In his dying moments, Snape gave Harry Potter his memories, which revealed his lifelong love for Lily and his true loyalty to Dumbledore. After viewing the memories in the Pensieve, Harry understood Snape's profound sacrifice, later naming his second son Albus Severus Potter and describing Snape as “probably the bravest man I ever knew.”
Snape is consistently described as a thin man with sallow skin, a large, hooked nose, and greasy, shoulder-length black hair which he wore curtaining his face. He had cold, black, empty eyes and yellowed, uneven teeth. He typically dressed in sweeping black robes, which made him resemble an “overgrown bat.” His personality was a complex and carefully constructed facade. Outwardly, he was sarcastic, caustic, vindictive, and cruel, holding deep-seated grudges, especially against Harry Potter for his resemblance to his father, James Potter. However, beneath this bitter exterior lay immense courage, a capacity for deep and enduring love, and unwavering loyalty. He was a master of deception, able to fool even Lord Voldemort, the most accomplished Legilimens known. His entire public persona was a mask to protect his true role as a spy for the Order of the Phoenix.