His friends might be divided. Some who are more inclined to support Olympus might be at odds with Percy. For example, Annabeth, who has a certain respect for the gods, could face a dilemma in choosing between Percy and Olympus.
It could also affect the enemies of Olympus. They might see Percy as an ally or at least a potential tool to use against Olympus. This could change the power dynamics in the whole 'Percy Jackson' universe, as new alliances might form and old ones might break.
Maybe he feels betrayed by the Olympians. They often have their own agendas and don't always consider the well - being of demigods like Percy. For example, they might send him on dangerous quests without proper support.
Obviously, Percy would be one of the main characters. And probably the Olympian gods like Zeus, Poseidon, Athena etc. would also play important roles as he is raised in their domain.
Grover could also be a major character. As Percy's best friend, he would probably be involved in trying to stop Percy if he thinks Percy has gone too far. Or, if he sees the corruption in Olympus, he may side with Percy. Grover's connection to nature means he could play an important role in the events that unfold, like using nature spirits to either protect Olympus or aid Percy depending on his stance.
Annabeth could be a main character. She might be desperately trying to find Percy after he jumps off Olympus. She could use her wisdom and strategic skills to track him down, facing various obstacles along the way, like mythical beasts or other unfriendly demigods. Another character could be Grover. He could sense Percy's distress and join Annabeth in the search, using his nature - related powers to help them.
Ares could be a likely character. He's always been somewhat of a wild card in the Percy Jackson series. He might betray Percy for his own amusement or to gain more influence in Olympus. Another could be Zeus. He's often paranoid about his power and might see Percy as a threat and betray him to protect his throne.
Grover might also be an ally. His connection to nature could be useful in Percy's new role. For example, he could help Percy understand any nature - related aspects of Olympus or deal with nature spirits in the realm. Also, some of the more benevolent gods like Poseidon (Percy's father) and Athena (Annabeth's mother) might side with Percy, at least to some extent, as they have their own interests in seeing Percy succeed in maintaining order in Olympus.
His hatred might make him more distant from the other demigods who still have some respect or hope for Olympus. They may not understand his extreme feelings and this could create tension.
Obviously, Percy Jackson is the central character. The Olympians such as Zeus, Poseidon, and Athena are likely to be involved as the ones doing the betraying. Other demigods like Annabeth Chase could also be part of the story. She might be torn between her loyalty to Percy and her respect for the Olympians. There could also be minor gods and goddesses who either side with Percy or the Olympians, depending on their own motives and relationships. For example, Hades might see an opportunity to gain more power if Percy is out of the picture, or he could help Percy out of a sense of fairness.
There might also be some of the gods as main characters. For example, Poseidon, Percy's father. He could be involved in protecting Percy and guiding him in the new setting of Olympus, while also dealing with his own affairs among the other gods.
Well, Percy is obviously one of the main characters. Since it's about him growing up on Olympus. Annabeth might also be a major character as she has a close relationship with Percy. She could be visiting him on Olympus or they could be having some long - distance communication that affects the story.