Snape's back story is quite tragic. He was a half - blood wizard, bullied as a child. He was in love with Lily Evans, Harry Potter's mother. But his association with the Death Eaters in his youth, due to his fascination with the Dark Arts and his desire for power and acceptance, put him on a difficult path. His love for Lily led him to become a double agent, spying on Voldemort for Dumbledore. This was a dangerous game, and he had to constantly deceive those around him.
Love for Lily is a key element. It changed his entire life. Also, his early involvement with the Death Eaters is important. And his decision to become a double agent.
One possible reason could be that Snape is starting to see Harry in a different light. Maybe he realizes that Harry has been through a lot and has a moment of empathy. It could also be a sign of a deeper, unspoken connection developing between them in the alternate universe of the fanfiction.
Dumbledore is also a character often paired with Snape in such fanfictions. Snape's loyalty to Dumbledore in the original story is complex. When he travels back, their relationship could be rewritten. Snape might confide in Dumbledore about his time - traveling experiences and they could work together more closely to prevent future disasters. Additionally, James Potter could be paired with Snape in a sense that Snape tries to change their relationship dynamic by going back in time, either to befriend him or to avoid the conflicts they had in the past.
Snape's character development could take a very different turn. He may start to value life more, not just Harry's but also those around him. In the original, his focus was mainly on his own pain and his loyalty to Dumbledore. But going back in time, he realizes that every action he takes can have a huge impact on the future. This could lead to him becoming a more empathetic character. He might also become more of a hero in the eyes of others, which is a big change from his somewhat villainous reputation in the original story. He could start to see himself in a new light and strive to be a better person not just for Harry's sake but for the sake of the entire wizarding world.
In the movie, after Lily's death, Snape's heart had died. His only purpose in life was to follow Dumbledore's arrangements to protect Harry. After Dumbledore's death, he had an unfinished task, which was to tell Harry Dumbledore's secret. If he had resisted Voldemort and Nagini, he would have been killed on the spot by Voldemort's Avada Kedavra Curse, which would have prevented him from completing his task, so he did not resist. In the novel, however, Snape did not intend to wait for death from the beginning. When Voldemort expressed that the Elder Wand would not be fully his as long as he lived, Snape tried to resist and raised his wand. But Voldemort made a feint by slamming the Elder Wand into the air, and Snape let his guard down, thinking he was temporarily safe. Then Nagini attacked him unexpectedly, biting his neck, making it difficult for him to free himself and cast the spell, not because he did not want to fight back. Harry Potter and the Order of the Phoenix is not enough. Please click to read the novel!
It can add a lot of tension. For example, if Hermione constantly challenges Snape, it could create a rift between Gryffindor and Slytherin students. The Gryffindors might side with Hermione, while the Slytherins would support Snape. This would lead to more inter - house rivalries and drama within the Hogwarts setting.
It's popular because it gives Snape a chance to rewrite his story. He was such a complex and tragic character in the original series, and in these fanfictions, he can correct his mistakes or make different choices.
One interesting Snape back in time fanfiction is 'Snape's Time - Turned Adventure'. In this story, Snape goes back to his Hogwarts days with new knowledge and tries to change some of the events that led to his difficult life. Another is 'Back to the Past: Snape's Redemption' where he has the chance to right the wrongs he did in the past, especially regarding his relationship with Lily.
It would definitely shake things up. The Gryffindors and Slytherins have a long - standing rivalry. With Harry, a well - known Gryffindor, befriending Snape, a Slytherin, it could start to break down some of those barriers. Students might be more open to interacting with those from different houses.
Bellatrix Lestrange could also be a character who interacts with Snape. If Snape goes back far enough, he might try to influence Bellatrix's path and keep her from becoming such a devoted Death Eater. This could have a major impact on Voldemort's power and the overall balance of the wizarding world.