Maybe an Atlantean sea - witch would be Percy's ally. She has powers that are different from the regular Atlanteans and she sees potential in Percy. She helps him with her magic when he's in difficult situations. There could also be a young Atlantean inventor who creates gadgets that come in handy for Percy. They work together to improve the safety of Atlantis and also to help Percy with his personal quests.
One of his main allies could be an Atlantean princess. She could be well - versed in the ways of Atlantis and help Percy navigate the complex social and political structures. Another ally might be an old Atlantean sage. The sage would have a vast knowledge of Atlantean magic and history, and could offer Percy valuable advice. There could also be a merman who is an outcast like Percy in some ways. They bond over their differences and help each other out in tough situations.
Annabeth would definitely be one of his main allies. She has always been by Percy's side and her intelligence would be crucial in helping him navigate any challenges he faces while being 'god - like'. Grover could also be an ally. His connection to nature and his loyalty to Percy would make him a great support. Another possible ally could be Nico. With his powers over the Underworld, he could offer a different perspective and unique assistance when Percy is dealing with threats related to the afterlife or the darker aspects of his new - found status.
Eragon could be one of Percy's allies. Eragon has his own set of powers and knowledge of Alagaesia. Percy and Eragon could combine their skills, with Percy's control over water and Eragon's magic and sword - fighting abilities. They could also share their different cultural knowledge, Percy from the world of Greek mythology and Eragon from the world of Alagaesia.
It could be a power - hungry Atlantean noble who wants to rule not just Atlantis but also the surface world. He sees Percy as a threat to his plans and tries to stop him at every turn.
Maybe there is a scientist or an inventor who becomes Percy's ally. This person could be creating new weapons or gadgets that Percy uses in battle. Their alliance could be crucial in giving Percy an edge in the fight. For example, the inventor might create a special type of grenade or a device that can jam the enemy's communication lines.
Chiron could be an important ally. With his vast knowledge of the demigod world and its history, he could guide Percy in making just decisions. Also, some of the minor gods who have been overlooked in the past might side with Percy, seeing him as a champion of a more fair and inclusive form of justice.
The Hunters of Artemis could be allies. Their leader, Artemis, respects wisdom and knowledge. Her hunters, who are skilled in archery and survival, could join forces with Percy. They could help him in his quests related to wisdom, like finding ancient artifacts that hold the secrets of wisdom. Also, some of the minor gods who have been overlooked might see Percy as an opportunity to gain more influence. They could offer their unique powers and knowledge as allies to Percy in his new role.
If Percy joins the Titans, his allies could be some of the lesser - known Titans who are tired of the constant fighting. They might see Percy as a way to bring about change. Enemies? Well, the Titans who are fully committed to overthrowing the Olympians and establishing their own tyrannical rule would be against him. Also, Poseidon, his father, might be conflicted about Percy's choice and could end up being an enemy if Percy doesn't change his course.
The Titans could still be antagonists. Even though Percy is raised by Chaos, the Titans might see him as a threat to their plans of overthrowing the Olympians. They could try to capture or kill him to prevent him from interfering.
The main villain could be a power - hungry Atlantean sorcerer who wants to use the power of Atlantis to rule both the underwater world and the surface. He might see Percy as a threat to his plans and try to eliminate him.
Perhaps some minor gods or spirits who thrive in chaos could be allies. For example, a god of randomness or a spirit of disorder. They would understand the nature of chaos better than most and could offer unique powers or knowledge to Percy. They might also be able to guide him through the chaotic landscapes and help him when he's in a tight spot.