Well, in fanfiction, if Percy is the Champion of Pontus, his story would be filled with more mystery. Pontus is an ancient and powerful entity. Percy might be called upon to do things that go against the traditional ways of the Olympian - influenced world he's used to. He could discover secrets about the origin of the sea and his own powers that were previously unknown. This would not only make for an exciting read but also show how Percy can adapt and make his own path even when given a very different role.
One possible plotline could be Percy having to fight against other champions of different deities who see him as a threat. Another is that he has to find a way to combine his new role with his loyalty to his friends and the Olympians. For instance, he may be forced to make a choice between following Pontus' orders that might seem harsh to his friends or standing by his friends and risking the wrath of Pontus.
The heir of Pontus is the central figure. They will have their own personality, goals, and struggles. Alongside them, if the fanfiction is set in the Percy Jackson universe, characters like Grover could make an appearance. Grover might be involved in guiding the heir in some way, or he could be a sidekick during their adventures. Also, there could be villains in the form of other powerful beings from the sea or those who want to take advantage of the heir's power. For example, a sea witch - type character who tries to manipulate the heir.
Well, it could be about Percy having to deal with the powers and heritage that come with being the adopted son of Pontus. Maybe he discovers new underwater abilities that are different from his Poseidon - given powers. He might also have to face enemies who are after the secrets Pontus has.
Well, one interesting plot could be the heir of Pontus having to deal with new and strange sea monsters that are loyal to Pontus. They might have unique powers and abilities that the heir has to figure out how to control or defeat. Another plot could involve a power struggle between the heir and other demigods who fear the power of Pontus. And sometimes, there are plots where the heir discovers long - lost secrets about Pontus' realm and has to protect them from falling into the wrong hands.
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.
The plot could involve Percy's journey to discover the true meaning of being the son of Gaea and Pontus. He could be on a quest to find out more about his parents' realms and how they interact with the world of the demigods. Along the way, he may encounter mythical creatures that are related to Gaea and Pontus, and he has to either fight them or make peace with them. There could also be a sub - plot about Percy's relationships with his friends at Camp Half - Blood, as they struggle to accept this new side of him.
One possible fanfiction could be about Percy Jackson seeking the guidance of Hestia, the goddess of the hearth, who has now become a champion in some way. Maybe she is a champion against a new threat to the demigod world. Percy could learn new skills or gain unique powers from her. For example, powers related to home and family, which could be used to protect Camp Half - Blood in a different way than before.
In fanfiction, Percy Jackson as the champion of Hades could bring a whole new dynamic. He might have to deal with the darker aspects of the Underworld. For example, he could be in charge of ensuring the souls are properly sorted, which is a huge responsibility.
In some fanfiction, Percy Jackson might be depicted as a champion of Kronos, but this goes against his character in the original series. In Rick Riordan's official books, Percy is a hero who stands against Kronos and his evil plans.