In fanfiction, the politics and intrigues within Olympus might be depicted in a way that makes Percy disgusted. The backstabbing and power - hungry nature of some of the Olympians could be too much for him to bear, so he hates Olympus.
It could also be that in the fanfiction, Percy is given a new power or ability that Annabeth sees as a threat. Or perhaps Percy is made to side with someone Annabeth dislikes, causing her to 'hate' him in that fan - created story. This shows how different plot elements in fanfiction can change the dynamics between characters.
It might be that in the fanfiction, Calypso represents something that Percy has come to dislike. Maybe she is associated with a force or an idea that Percy opposes, like a form of confinement if she tries to keep him on the island in a more extreme way than in the original tales.
Perhaps the fanfiction is set in an alternate universe where something has happened to change Percy's feelings towards Annabeth. For example, if there was a betrayal in the fan - created story that made Percy turn against her.
One reason could be jealousy. Maybe in the fanfic, Annabeth gets more attention or praise for her skills and Percy feels left out or overshadowed, which turns into hatred. Another possibility is that there's a rift caused by their different approaches to solving problems. If Annabeth's logical thinking clashes too much with Percy's more instinctive ways, it could lead to resentment.
One possible reason is that their personalities clash. Percy is often portrayed as a more outgoing and confident character, while Nico is more introverted and brooding. In a fanfic, this could lead to misunderstandings and animosity between them. For instance, Percy's bold actions might seem reckless to Nico, causing him to dislike Percy.
One reason could be jealousy. If Percy starts paying more attention to the child than to her, she might start to resent the child. It's a common trope in stories where a new addition to a relationship, like a child, can cause jealousy issues.
One possible reason could be to create a tragic story. Writers might want to show how the world of the story would be affected by the loss of such a central character like Percy.
One possible reason is that the person may find the fan - made interpretations of the Pokemon world too far - fetched. For example, some fanfictions might give Pokemon abilities that are completely against the established rules in the official games or anime. This can be off - putting to those who like the consistency of the official lore.
Maybe he feels betrayed by the Olympians. They often have their own agendas and don't always consider the well - being of demigods like Percy. For example, they might send him on dangerous quests without proper support.
He may dislike it because he feels that it undermines the real struggles and achievements of the ninja. In fanfiction, things might be made too easy or unrealistic. He has fought tooth and nail for everything in his ninja life, and seeing it made into something that doesn't represent that in fanfiction would make him hate it.