Severitus

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

Snarry is the slash ship between Harry Potter and Severus Snape.

Canon
From the day Harry set foot in Hogwarts, he and Snape loathed each other. Despite the fact that Snape was committed to honoring 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 harbor 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 (Severitus)
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.. They share trauma from the war and were also guided into a certain positions by Dumbledore whom they had to trust but were never given the whole plan/particular information.

So, they can understand each other, do have a lot in common and I don't think they'd be anything else but brutally honest with each other.

Romantic (Snarry)
Snarry has been popular long before the Lily reveal when the series was ongoing. A lot of the classic Snarry fics were written between 2001-2005. This was when Snape's motivations were still not known, so a lot of writers wrote a darker, complicated dynamic with power imbalances between the two.

On AO3, this ship is the most written ship for Snape and the second most written for Harry - with similar (and sometimes higher) popularity on FFN.net.

Fans of this ship loves enemies-to-lovers and redemption arcs, their positions in the story and roles in each other's lives promises an amazing potential dynamic. Snape and Harry are also mirror images of each other in many ways and have a lot in common. They both were abused, bullied, half-bloods who grew up in the muggle world and whose lives were changed by Voldemort. Snape is also pretty much responsible for everything that went wrong in Harry's life, and from Snape's pov, Harry is an impersonification of all Snape's sins and mistakes, and a living reminder of everything that's wrong in Snape's life, a symbol of all the betrayals - his own and those inflicted upon him..

In Snarry, a lot of post-war stories focus on the similarities between Harry and Snape and the dynamic of them working together. Both of them had a difficult childhood, wher they found home in Hogwarts, both of them like power, both of them had a vital role in the war with Harry as the weapon, and Severus as the tool. Both surviving so much danger. All Severus did to keep Harry alive over the years. How important he was as a spy on the DARK LORD. Both just used and seen as pawns and pushed around, Severus useful for his skills and his connections while Harry useful for his destiny.

Fandom
FAN FICTION


 * Harry/Severus on FanFiction.Net