Who could be the main antagonist in a 'Percy Jackson Son of Kronos' fanfiction?

It could be one of Kronos' old allies who feels betrayed that Percy is now in a position of power. Maybe someone who was promised a lot by Kronos but didn't get it.

In this fanfiction, it could be some of the Titans who are still loyal to Kronos' old ways. They might see Percy as a tool to bring back Kronos' full power. They would try to manipulate Percy into joining their cause, and when he refuses, they become the main antagonists trying to either kill him or use his power against his will. Another possible antagonist could be a powerful demigod who is jealous of Percy's new - found status and wants to take it for himself.

The Olympian gods could be the main antagonists. Since Percy is the adopted son of Kronos, they might see him as a potential threat and try to stop him before he can fulfill any of Kronos' possible plans. They may send their demigod heroes after him.

A group of rogue sky spirits might serve as the main antagonists. They are jealous of Percy's status as the 'Son of the Sky' and want to steal his powers. They could be constantly causing chaos in the sky, like creating dangerous storms and attacking flying creatures. Percy would have to figure out their motives and stop them before they cause too much damage. These sky spirits could have their own hierarchy and leader, making them a formidable foe.

Perhaps an ancient and evil creature that has a grudge against Oin. Since Percy is Oin's son, this creature targets him. It could be a monster that was once defeated by Oin and now wants revenge by going after his son.

Another option could be a corrupted demigod. Maybe a child of a minor Egyptian god who is jealous of Percy's status as Son of Sobek. This demigod could form an alliance with some dark forces and try to undermine Percy at every turn, creating all sorts of challenges for him.

Perhaps an ancient sea god who was once an enemy of Pontus. This god could see Percy as a threat because of his heritage. He would use his own minions, like sea serpents and murlocs, to attack Percy and those he cares about. He might also try to corrupt Percy, tempting him with power to turn against his friends.

It could be a powerful Titan who escaped from Tartarus and wants revenge on Zeus by targeting his son Percy. This Titan might have unique powers that make him a formidable foe.

The main character is surely Percy Jackson. But in this 'son of kronos percy jackson fanfic', new characters might be introduced that are related to Kronos' side of the story. However, the classic characters like Annabeth Chase are bound to be there too. She would be crucial in Percy's journey as she often is in the original stories. Grover Underwood, Percy's satyr friend, would also be a mainstay. His loyalty and friendship with Percy would be tested and explored in this new narrative where Percy has this unexpected connection to Kronos.

A powerful Titan who sees Percy as a threat to his plans. Since Percy has the power of Zeus and Poseidon, he could potentially stop any chaos the Titan wants to create. The Titan might try to turn Percy's friends against him or find a way to strip him of his powers.