Sometimes in fanfiction, the plot demands a big twist. So the author makes Annabeth betray Percy to shock the readers. It could be a completely out - of - the - blue reason like she suddenly decides she doesn't like Percy's friends and since he won't abandon them, she betrays him.
One possible reason could be jealousy. Maybe she sees Percy getting more attention or praise than her in the fanfic world, and that envy turns into betrayal. Another reason might be a misunderstanding. For example, if there's some misinformation spread about Percy that makes Annabeth believe he's done something really bad.
Misunderstandings about their future plans often lead to fights. Percy might want to focus on one type of adventure while Annabeth has other ideas. They argue about it, but in the end, the love between them overcomes the differences and they kiss. This shows how their relationship is complex and full of different opinions that need to be resolved.
Well, one possible reason could be that Percy made a really stupid decision without consulting Annabeth first. Like, if he went off on a dangerous mission on his own when they were supposed to be a team. Annabeth is a very strategic person and she might feel betrayed or extremely frustrated by such actions.
It could also be due to some sort of magic or mind - control. A powerful enemy might have cast a spell on Annabeth, forcing her to turn against Percy. In this case, it's not really her own will but the result of external manipulation.
In some fanfictions, Annabeth could abandon Percy because of a prophecy. If the prophecy seems to imply that being with Percy will lead to a great disaster, she might choose to leave to protect him or the world. Also, it could be due to a personal growth arc for Annabeth. She may realize that she has been too dependent on Percy in the past and decides to go off on her own to find her true self, leaving Percy behind.
One possible reason could be a misunderstanding. Maybe Percy did something that Annabeth misinterpreted, like being overly friendly with another character which made her jealous and led to her rejection.
One reason could be a shift in the plot where Annabeth's character development leads her to realize she and Percy are not compatible in the way they were initially thought. Maybe she has new goals or a different understanding of herself that makes her feel she's better off without Percy in the fanfiction world.
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.
One possible reason could be Percy's recklessness. He often jumps into dangerous situations without thinking fully, and Annabeth, being the more strategic one, might get frustrated and yell at him. For example, if Percy decides to face a powerful monster alone just to prove himself, Annabeth would be worried and angry at his lack of caution.
Maybe Percy has shown some uncontrollable power that scares Annabeth.