Well, it could be that Voldemort spoils Harry in fanfiction by taking away his normal life. Voldemort might use his power to isolate Harry from his friends at Hogwarts. He could put spells on the school or the people there to make them shun Harry. This would not only make Harry lonely but also disrupt his growth as a wizard and a person.
In certain fanfiction scenarios, Voldemort may spoil Harry by targeting his relationships. He might try to turn Harry's closest friends against him. By using his Death Eaters or his own dark charm, he could create misunderstandings between Harry and his friends like Ron and Hermione. This would break Harry's support system and make him more vulnerable to Voldemort's further attacks.
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, 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.
It might start with Voldemort's initial curiosity. He realizes Harry is more than just a threat. So he begins to observe Harry closely. As time goes by, Voldemort may start to feel a strange sense of connection, like he's the only one who truly understands Harry's power.
Well, in such fanfiction, Voldemort's possessiveness might show through his constant attempts to control Harry's actions. He may try to isolate Harry from his friends and allies, wanting Harry all to himself in a very dark and twisted way. For example, he could use dark magic to keep Harry in a certain place or manipulate situations so that Harry has no choice but to be near him.
It could start with a lot of animosity on Harry's part, but as he is trained, he might start to see Voldemort in a different light. Maybe he begins to understand Voldemort's motives, though not necessarily agreeing with them.
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.
In some fanfictions, Harry might show off his strong friendships, like his bond with Hermione and Ron. This could make Voldemort jealous as he has no such loyal comrades. Voldemort is often alone in his pursuit of power, while Harry is surrounded by people who love and support him.
Harry could also try to reason with Voldemort. He might remind Voldemort of the prophecies and how killing him might not be in Voldemort's best interest. He could also try to appeal to any bit of humanity that might still be left in Voldemort, although that's a long shot.
Well, in some fanfictions, Harry might use some hidden magic he discovers in Azkaban. Maybe he finds a way to turn the Dementors' power against Voldemort. Since Dementors can suck out a person's soul, Harry could somehow direct them towards Voldemort, weakening him enough to deliver the final blow.
Harry might use his wits and the environment around him while in captivity. For example, if he's held in a place with magical artifacts, he could use them to his advantage. He could break the chains that bind him with a spell - enhanced object and then make his way to Voldemort and defeat him.