It could be that the entire camp system, which he once believed in, failed him. If the camp's leadership made decisions that put Percy at a disadvantage or endangered his life, he might feel betrayed. Chaos could then seem like a haven, a place where he can start anew and not be bound by the rules and expectations that have let him down.
One possible reason could be that his friends wrongly accused him of something major. For example, if they thought he was secretly working for an enemy and didn't give him a chance to explain. Another reason might be that the gods themselves turned against him unjustly, perhaps because they feared his growing power and influence. This could make Percy feel so alone and betrayed that he decides to join Chaos as a form of revenge or to find a new place where he is accepted for who he is.
Maybe Percy was betrayed by someone he deeply trusted, like a close friend or a family member. If this person spread false rumors about him or directly harmed him in some way, it would be a huge blow. He might then see joining Chaos as an opportunity to break free from the world that has turned against him and gain power to protect himself from further harm.
One possible reason could be jealousy among his peers. Maybe someone was envious of Percy's skills or popularity and spread false rumors about him, leading to his betrayal. For example, if Percy had a special power or was favored by a certain group, others might feel left out and decide to turn against him.
He could be seeking revenge. After being betrayed, Percy might see Shield as a means to get back at those who wronged him. By joining Shield, he may think he can gain the power and resources needed for revenge.
One possible reason could be jealousy among other characters. Maybe there are those who envy Percy's powers and leadership, Jason's status as a hero, or Nico's unique abilities. Another reason might be a misunderstanding. For example, they could be wrongly accused of a crime they didn't commit, which leads to others turning against them.
Percy might initially be confused. He might start to question everything that led up to the betrayal. His mind could be racing, trying to figure out if there were any signs he missed. He might also be hurt, but the confusion could overshadow the pain at first as he tries to make sense of the situation.
After joining Chaos, Percy's character evolves into a more complex one. He is no longer the naive hero he once was. He gains a new sense of purpose. With Chaos, he might be involved in more dangerous and morally ambiguous situations, which forces him to re - evaluate his values. He may become more independent and self - reliant, relying less on the support he used to get from his old friends and more on his own skills and the new allies he finds in Chaos.
One possible reason could be jealousy. Maybe Percy has some special abilities or achievements that make others envious. For example, his connection to the sea could be seen as a huge advantage that others might resent. Another reason could be misinformation. Someone might spread false rumors about Percy, leading others to believe he's done something wrong when he hasn't. It could also be that there's a misunderstanding about his relationship with Annabeth. Some might think he's getting special treatment from her or the other way around, which causes them to turn against him.
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, perhaps Percy is betrayed by his friends or allies who he thought he could trust. This betrayal could be due to jealousy, a misunderstanding, or someone's hidden agenda. As a result, Percy feels so hurt and angry that he decides to join the Hunt. In the Hunt, he might find a new sense of purpose, new friends who understand his pain, and he could start to train hard to become a more powerful fighter. He may also seek revenge against those who betrayed him.
Well, perhaps Percy could be disillusioned with his current situation in his normal world. He might see the chaos army as a way to break free from the constraints he's felt. He could start off as an outsider in the chaos army, having to prove himself.
If Percy Jackson joins Chaos in fanfiction, it would likely change his entire perspective. He's used to the world of Greek gods and demigods. But in the realm of Chaos, there are no such clear - cut rules. He could be sent on wild adventures across different dimensions. He might have to face enemies that are far more powerful and unpredictable than anything he's encountered before. And his relationships with his friends from Camp Half - Blood would also be put to the test as he becomes something more than just a demigod.