The best FF i've ever read !
Hope you'll enjoy them
Book 1 : Severus Snape was born a half-blood wizard, son of the witch Eileen Snape (née Prince) and Muggle Tobias Snape. His grandmother was an healing witch.
He met Lily Evans when he was nine, and became a close friend of hers.
In 1971, he began his first term at Hogwarts School of Witchcraft and Wizardry where he was sorted into Slytherin. Lily Evans, unfortunately, was in a rival house, Gryffondor. Severus became the immediate enemy of James Potter and Sirius Black and was a frequent victim of their bullying, but he was also snubbed by the bullies in Slytherin House, many who were pure-blood supremacists. So he developed a passion for the Dark Arts at a young age, which increased as his desire for revenge grew stronger. He got a surname: the Cursemaster.
Severus Snape protégé of Bellatrix Black, Snape joined the Death Eaters along with a group of his fellow Slytherins. He became the Potion master of his teammates.
Shortly before Lily Evans was murdered by Lord Voldemort, Snape changed sides and became a double agent during the Second Wizarding War. With tremendous difficulty, he was able to prevent Lord Voldemort from learning the truth about his loyalties.
After the Dark Lord defeat, Snape, as a known Death Eater, was hunted by the Aurors bureau and sentenced to Azkaban, but Dumbledore obtained to keep him in at Hogwarts instead, as Potions professor and head of Slytherin, another sort of prison.
Severus Snape suffered terrible remorse when Lily, the woman who he always loved, died as a result of his actions. Devastated, he stayed at Hogwarts.
Then Harry potter arrived à Hogwarts. him and Severus Snape detested each other almost immediately.
Snape treated Harry with maximal coldness and never missed an opportunity to cause him troubles. But in reality, he protected Lily’s son on numerous occasions.
During the 1995-1996 school year, with Voldemort having returned to his body, Snape carried on with his work as a doubled agent for Dumbledore and the Order of Phoenix. When questioned by Bellatrix about his loyalties, Snape claimed to have been working for Lord Voldemort.
After Dumbledore death, Snape was named Headmaster of Hogwarts, and used his position to discreetly protect the students and continued to receive instructions from Dumbledore's portrait.