One possible plotline could be that Snape discovers a hidden vulnerability in Voldemort. Maybe it's related to his Horcruxes. Snape, being the intelligent and resourceful character he is, figures out a way to destroy all of Voldemort's Horcruxes without Voldemort suspecting. Then, he uses his powerful magic skills, perhaps a combination of dark and light magic, to directly confront and kill Voldemort.
One interesting fanfiction could be 'Snape's Redemption: Voldemort's End'. In this fic, Snape uses his deep knowledge of the Dark Arts against Voldemort. He discovers a long - forgotten spell that can counter Voldemort's main source of power. It's a really exciting read as it shows Snape's cunning and his determination to finally put an end to Voldemort's reign of terror.
There could also be interesting developments for Harry Potter in such fanfictions. Harry might have a different reaction to Snape. Instead of the complex and often conflicted relationship they had in the original story, Harry could fully embrace Snape as a hero and perhaps learn more about Snape's past and his motives in a more positive light. This could lead to a much closer bond between them, with Harry seeing Snape as a mentor figure in a new way.
After Harry kills Voldemort in the graveyard in the fanfiction, the magical balance might shift. With Voldemort gone, some of the dark magic that was prevalent might start to fade away. The Hogwarts School of Witchcraft and Wizardry could see a new golden age. New spells and magical theories might be explored as the fear of Voldemort no longer holds back the wizarding scholars. Harry himself might start to travel around the world to spread the news of Voldemort's defeat and also to learn more about different types of magic. His friends would also have new opportunities, like Hermione might be able to further her studies without the constant threat of Voldemort and Ron could finally relax and enjoy a more peaceful life at the Burrow.
One possible reason could be that Snape fails to deliver crucial information. Voldemort is a very demanding and unforgiving master. If Snape doesn't give him accurate details about the Order of the Phoenix's plans, for example, Voldemort would surely be enraged and punish him.
The wizarding world would likely be in a state of shock and then celebration. People would start to see Azkaban in a new light, perhaps no longer as just a place of horror but also as the site where the great evil was finally vanquished.
There could be. Fanfiction allows for all kinds of wild ideas. Given that Percy is a character in the Harry Potter series and Voldemort is the main villain, it's not surprising that someone might come up with a story where Percy manages to kill Voldemort. It might be a really unique read, delving into how Percy, with his own set of skills and personality traits, could achieve such a feat.
Harry Potter often features prominently. His relationship with Snape is complex in the original series, and in fanfiction involving Snape and Voldemort, his role can be further explored. For example, how he reacts to Snape's interactions with Voldemort and whether he can figure out Snape's true motives sooner.
In some fanfictions, Snape might be working with Voldemort because he has been blackmailed. Voldemort could have found out some deep, dark secret about Snape and is forcing him to cooperate. This could be related to Snape's past or something he has done that he doesn't want to be made public.
In fanfiction, Snape's relationship with Voldemort is often complex. Snape was a double - agent, so on the surface he seemed to be loyal to Voldemort. But in fact, he was working for Dumbledore. This creates a lot of tension in their relationship in fanfictions. Some fanfictions might explore how Snape managed to deceive Voldemort for so long, and the psychological stress he endured while being in such a precarious position.