Severitus

Severitus is the familyship between Harry Potter and Severus Snape from the Harry Potter fandom.

Canon
From the day Harry set foot in Hogwarts, he and Snape loathed each other. Despite the fact that Snape was committed to honouring Lily's sacrifice, he could not bring himself to judge the boy objectively because of the connection to James Potter, who bullied him in his school days. Indeed, Snape was filled with nothing but contempt and bitterness towards Harry, who simultaneously reminded him of both Lily and James. Harry served as living proof of the fact that Lily had given her love to someone else, and Snape wasted no time in comparing him continually with his father.

During Harry's time at Hogwarts, Snape treated Harry viciously, both in class and out. He frequently derided the boy's abilities, bullied him in class and punished him whenever possible. He was also resentful and even somewhat envious of Harry's popularity, which he also equated with Harry's father. Although Snape threatened to have Harry expelled more than once, he never attempted to follow through — presumably because it would have led to Harry losing the protection surrounding him. However, never did he forget that Harry was also Lily's child, and much beyond bureaucratic rules, this led him to put the boy's safety in the most critical situation. When he learned that Dumbledore had intended for Harry to die all along, Severus remained horrified, seeing it as a calculated betrayal of Lily's memory.

When Harry helped Sirius Black escape, their relationship went under further strain, since Snape believed at that time that Sirius betrayed Lily to Voldemort whereas Harry had learned of his innocence, although Snape continued to put Harry's safety first. During the brief period in which Snape gave private Occlumency lessons, Snape relished in forcing Harry to relive his worst memories. During the early years, Harry associated Snape with his abusive and bullying ways but when Sirius died, Harry took savage pleasure in blaming Snape for having taunted Sirius about being useless, causing him to leave his hiding place and join the battle. Though Snape came to the aid of the Order as swiftly as possible, Harry blamed Snape mainly to ease his own guilty conscience about the entire incident. However, this was nothing in comparison to the retroactive rage Harry felt upon finding out that Snape was the one who relayed the Prophecy to Lord Voldemort, causing him to hunt down Harry and his family. When he later murdered Dumbledore, the hatred between them was sealed almost as personally as between Harry and Voldemort.

Only once did Snape ever truly see him as Lily's son, and that was in the moments right before he died. Following this, Harry was given access to all of Snape's concealed memories, which brought the former teacher's true intentions to light. When Harry discovered the love Snape had for his mother and the constant danger he put himself in to ensure his safety, his opinion of him changed completely. By adulthood, all of Harry's hatred of Snape seem vanished and looks as though he never harbour it. This can be seen through his request that a portrait of Snape be hung in the Headmaster's office at Hogwarts, which was not done immediately after Snape's death since he had abandoned his post. Furthermore, Harry gave his youngest son the name "Albus Severus", and told him that his Slytherin namesake was "the bravest man I ever knew."

Family
This ship is when a fanfiction describes a situation in which Snape becomes a father-figure to Harry in some way; this often involves Snape being obliged to adopt Harry after his parents' deaths or similar.

Romantic
The ship is disliked by many fans due to their age difference and the fact that the characters dislike each other for most of the series. Despite this, the ship has a large fanbase with plenty of fanfiction and fanart.

Fandom
FAN FICTION