One possible plot could be that Harry has a magical pet, perhaps a phoenix or a very intelligent owl. This pet discovers a hidden weakness of Voldemort. Harry, with the help of his pet's discovery, manages to defeat Voldemort in a final showdown. For example, the pet might find a magical artifact that can nullify Voldemort's dark magic, and Harry uses it to his advantage.
The pet could be a key factor in changing Harry's perspective. If it's a friendly and wise pet, it might give Harry new insights into Voldemort's motives, making Harry more determined to end him. For instance, if the pet was a magical cat that could communicate with Harry telepathically, it could share some deep secrets about Voldemort's past that fuel Harry's fight.
At first, it would probably be very tense. Harry would be suspicious of Voldemort's motives, and Voldemort would be cautious of Harry's potential to rebel. But as time goes on, they might develop a strange sort of understanding. Harry could start to see Voldemort as more than just a pure evil figure, and Voldemort might start to view Harry as something more than an enemy.
In the fanfiction world, the author could also give Percy some new powers or abilities specifically for this encounter. For example, he could have the power to nullify magic for a short time. This would be a huge advantage against Voldemort. Percy could then use his physical combat skills to overpower Voldemort and deliver the final blow. Another aspect could be that Percy's friends from Camp Half - Blood could help him in some way, like providing distractions while he goes in for the kill.
Maybe Draco discovers a powerful magical artifact that can defeat Voldemort and he decides to use it for the greater good, even if it means going against his family's past allegiances. He could then face many challenges and battles before finally being able to kill Voldemort.
Another option is to ask in Harry Potter fan groups on social media platforms like Facebook or Reddit. People in those groups are often very passionate about fanfiction and may be able to point you in the right direction.
Hermione could be a main character. She might be trying to find a way to rescue Harry from the timeout situation. Ron could also be there, supporting Hermione in her efforts.
In this fanfiction, it could be that Voldemort has a premonition. He sees that if Harry Potter dies, it will lead to a series of disasters that will also destroy his own plans. So, in order to preserve the balance or to keep his long - term goals intact, he saves Harry. For example, if Harry's death causes an uncontrollable chaos in the wizarding world, Voldemort's rule over the dark forces might be disrupted. So he steps in to save Harry.
The main antagonist could be Dumbledore. Since Harry has joined Voldemort, Dumbledore would see Harry as a threat to the good of the wizarding world. Dumbledore would try to bring Harry back to the right side, and they would end up in conflict.
Well, in such a fanfiction, Harry being Voldemort's snake might initially make their relationship more of a master - servant one. But as the story progresses, Harry could start to resist Voldemort's control, leading to a more adversarial relationship.