Perhaps Annabeth's dad has some old - fashioned ideas. He might believe that Percy doesn't have the right qualities to be with his daughter. He could also be jealous in a way. Percy is an important person in Annabeth's life and her dad might feel left out or that Percy is taking his place in a sense.
It creates conflict. For example, Annabeth might have to choose between her dad and Percy, which adds drama to the story.
Maybe in some fanfictions, the writers change the characters' personalities too much. Annabeth is a strong - willed character, and if Percy is portrayed in a way that goes against their original relationship dynamic, she might seem to 'hate' him in that fictional context.
It could be that the fanfiction plots are so convoluted. For example, the writer might create some really out - of - character situations for Percy and Annabeth. If Percy is constantly put in scenarios where he's made to be at odds with Annabeth in ways that don't feel true to the original series, it could give the impression that he hates her in the fanfiction.
It could be that the way the child is written in the fanfiction goes against Annabeth's character. For example, if the child is depicted as being overly needy or bratty and Annabeth, who values independence and order, just can't stand it. Also, it might be that the existence of the child changes Percy in a way that Annabeth doesn't like. Like Percy starts to neglect her in favor of the child.
Well, at first, Annabeth's dad might be quite hostile. He'd be worried about his daughter getting involved with someone like Percy who is constantly in danger. But if Percy shows his loyalty to Annabeth and his good nature, like by being polite and showing respect for Annabeth's family, her dad could gradually change his attitude. Maybe he'd start to see Percy as a brave young man who can protect Annabeth rather than a threat.
Maybe they have a different taste in literature. They might prefer other types of stories and not be into the fanfiction genre, especially those related to Percy and Annabeth.
Maybe in some fanfics, the author wants to create a new and controversial plot. They might make Percy hate Annabeth due to some misunderstandings, like a miscommunication about a quest or Percy believing Annabeth has betrayed him in some way.
Perhaps in this high school fanfiction setting, Percy has a different group of friends who don't like Annabeth. Their influence on Percy gradually makes him develop a dislike for her. You know, peer pressure can sometimes change a person's attitude towards others.
In the fanfiction world, when Percy meets Annabeth's dad, it could start off rocky. Her dad might be overprotective and see Percy as a threat to Annabeth's normal life. However, as they talk, Percy could share his heroic tales, not to brag but to show that he has the strength and courage to protect Annabeth. Annabeth's dad might then start to warm up to Percy, realizing that he is more than just a trouble - making demigod. Percy could also learn a lot about Annabeth's family background from her dad, which would strengthen his bond with her.
It could be that Annabeth has a misunderstanding about Percy. She might think he's a threat to her position or status at the camp, so she bullies him to try and keep him in check.