Well, in some fanfictions, the author might be exploring a 'what - if' scenario. For instance, if Annabeth had some sort of dark turn or was influenced by something bad. This could lead to her bullying Percy. Also, it could be an attempt to show Percy's growth through dealing with such a difficult situation. If he can overcome being bullied by someone he might have considered a friend, it could be a significant part of his character development.
One reason could be a misinterpretation of their characters. Maybe in the fanfiction, the writer wants to create a more complex or different dynamic between them. Another reason might be for the sake of drama. By having Percy bullied by Annabeth, it can create conflict and drive the plot forward in a new and unexpected way.
It could be because Percy is different. If he comes from a different background or has a unique personality trait, the bullies might target him. In the fanfiction, if Percy is from a different race or has an unusual way of speaking, the bullies might pick on him for not being like them.
Perhaps Percy made a decision without consulting Annabeth. In many fanfictions, Annabeth values being part of the decision - making process, especially when it concerns their relationship or a mission they're on. If Percy went off and did something like made a deal with a potentially dangerous character on his own, Annabeth would be furious.
One possible reason could be a misunderstanding. Maybe Percy said or did something that Annabeth misinterpreted. For example, he might have made a joke that she took the wrong way, thinking he was being disrespectful to her or her beliefs. Another reason could be that Annabeth is under some kind of magical influence that makes her act out of character and lash out at Percy.
Well, it could be due to a misunderstanding. Maybe Percy thought Annabeth did something wrong regarding a quest, like made a decision without consulting him. In fanfics, authors often play with such relationship dynamics.
One possible reason could be a misunderstanding. Maybe Percy made a decision without consulting Annabeth, thinking it was for the best, but she felt left out. For example, if he agreed to a dangerous mission without her input. Another reason might be jealousy. If Percy got a lot of attention from someone else, Annabeth could feel insecure.
In fanfiction, it could be because of their strong emotional bond. They've been through so much together that being apart makes Annabeth feel不安. Their adventures have created a deep connection where she's used to having him around, and without him, she feels incomplete and can't relax enough to sleep.
Percy might initially be confused. He would probably wonder why Annabeth, who was once his friend or ally, is treating him this way. So he could try to talk to her to find out what's wrong.
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.