What could be the reasons that Percy brother likes Annabeth fanfiction?

Maybe he likes it because he has a deep connection with Annabeth in the original story and the fanfic allows him to see different interpretations of their relationship.

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.

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.

One reason could be stress. Maybe they are in a really tough situation in the fanfiction, like facing a powerful enemy. Annabeth, being under a lot of pressure, snaps at Percy if she thinks he's not taking things seriously enough. Another possibility is jealousy. If Percy gets a lot of attention from someone else, Annabeth might snap out of insecurity.

One reason could be miscommunication. Maybe Percy misinterpreted something Annabeth said or did. For example, if Annabeth made a decision about a quest without consulting Percy, he might get angry and yell.