Hermione is often a very popular character. She's known for her intelligence and resourcefulness, and in fanfiction, she might come up with new spells or strategies to help Harry in his fight against Voldemort.
One interesting plotline could be an alternate universe where Harry and Voldemort have to team up against a greater evil. This flips the traditional dynamic on its head.
One great Snape vs Voldemort fanfiction is 'The Dark Mark's Secret'. It delves into Snape's complex relationship with Voldemort. Snape is constantly in a precarious position, having to play the double agent. The story shows how he uses his wits against Voldemort's brute power. Another one is 'Snape's Hidden Alliances'. It focuses on how Snape manages to outmaneuver Voldemort in some crucial situations. The characterizations are really well - done in both of these, making them engaging reads.
One interesting plot twist could be that Voldemort actually has a change of heart. Maybe in the fanfiction, he realizes the futility of his dark ways after seeing the strength of Harry's love and friendship. Another could be that Harry discovers a new, unexpected power within himself that is not related to his typical Gryffindor courage or his connection to Voldemort's soul pieces. For example, he might find he has the ability to manipulate time in a way that gives him an edge in the battle.
Harry often becomes more conflicted. He has always seen Voldemort as the ultimate evil, but now being mates, he has to re - evaluate his views. He might start to see the humanity in Voldemort, which makes him question his own beliefs and actions in the fight against the Dark Lord. For example, he may hesitate in battles more than before.
Often in fanfiction, their relationship can change drastically. They could end up as allies, which would require both of them to change. Harry would have to see past Voldemort's evil deeds, and Voldemort would have to let go of his hatred for Harry. This exploration of character change makes fanfiction so interesting.
The Gryffindors, of course, are usually very vocal in their support of Harry. They might cheer him on, offer their own magical skills if they can, and be ready to fight alongside him. The Slytherins can have a more complex reaction. Some might side with Voldemort out of fear or ambition, but there could also be Slytherins who see the wrong in Voldemort's ways and secretly support Harry. The Hufflepuffs would likely be focused on protecting the innocent within Hogwarts and providing a sense of stability and comfort during the chaos. And the Ravenclaws might be analyzing the situation, coming up with strategies to help Harry or trying to understand the deeper magic at play in the battle.
Maybe Harry uses some powerful and unexpected spells. For example, he could combine the Patronus Charm with a blasting spell. The Patronus might distract Voldemort while the blasting spell hits him hard.
In this fanfiction, the relationship between Harry and Voldemort would be full of contradictions. Voldemort adopts Harry for his own purposes, but Harry has his own will. In the beginning, Harry may be forced to follow Voldemort's orders out of fear. As time passes, he might start to question Voldemort's actions and ideology. Voldemort, seeing Harry's growing independence, could become more controlling. This could lead to a cycle of rebellion and suppression in their relationship. Harry may also find some common ground with Voldemort in their shared loneliness or desire for power, which would add more layers to their complex relationship.
In this fanfiction, Voldemort's character is explored in a way that challenges our traditional view of him. His seeing Harry abused might make him reevaluate his relationship with Harry. He may start to see Harry not just as the Boy Who Lived who he wants to defeat, but as a person who has suffered, much like he might have in his own way. Harry, on the other hand, is stripped of some of his heroic facade. His abuse makes him more relatable in a sense. We can see his pain and how it affects his actions and decisions, and also how he reacts to Voldemort's new - found interest in his situation.