It could be for the greater good as she perceives it. Annabeth might think that by betraying Percy, she can save more people or prevent a greater disaster. However, her perception might be wrong, and she realizes it too late after the betrayal has already occurred.
One possible reason could be that Kronos has somehow tricked her. Maybe he promised her something she desperately wanted, like power to protect her loved ones in a way she thought Percy couldn't. Another reason might be that she was brainwashed. Kronos could have used some dark magic or manipulation to make her believe that Percy was on the wrong side.
Well, it could be that in the fanfiction, the writer might have developed Annabeth's character in a way where she becomes disillusioned with Percy. Maybe she sees Luke as having something that Percy lacks, like a different kind of power or charm. Or perhaps there are some misunderstandings between Percy and Annabeth that Luke takes advantage of, pushing Annabeth towards the betrayal.
Then, she would probably be angry. Annabeth is a strong - willed character. She would feel betrayed and used, and her anger would fuel her to find out the truth. She might start her own investigation to figure out what's really going on with Percy, whether he's been influenced by someone or if there's another reason for his actions.
One possibility is that it could lead to Percy's downfall. If Annabeth, who has been his close ally and friend, betrays him, it might shatter his trust not only in her but also in others. He could become more isolated and vulnerable, making it easier for his enemies to target him.
Percy's reaction could also be one of self - doubt. He may start to question his own actions and leadership. He might think that he has done something wrong to push Annabeth away. However, his loyalty to his friends and the cause would eventually make him stand up against Kronos and try to bring Annabeth back to the right side.
If Annabeth betrays Percy in fanfiction, it would likely shatter Percy's trust. He has always relied on her, and this would be a huge blow. He might become more withdrawn and less likely to trust others in the future.
Percy would probably be extremely hurt. He trusts Annabeth deeply, so this betrayal would shatter that trust. He might feel angry at first, wanting to confront both Annabeth and Luke.
In the long run, Percy might grow from the experience. He could become more cautious in his relationships and less trusting. Or, if there's a chance for redemption in the fanfic, he might be open to forgiving Annabeth if she shows true remorse and has a valid reason for her actions. But initially, it would be a very difficult and emotional time for him.
In fanfiction, Percy and Annabeth's love can be depicted in various settings. It could be in the Camp Half - Blood, where they train together and their love story unfolds gradually. For instance, Percy might be clumsy at first when trying to show his affection, which adds a cute touch to the story.
Love is a big reason. She loves Percy deeply and is afraid of losing him. In the world of the fanfiction, there could be many threats to their relationship, so she holds on tightly.