Isis is also a possibility. She is known for her magic and wisdom. In the fanfiction, she could be seeking Percy's help to retrieve a powerful artifact that has been stolen from her temple. Percy, with his own set of skills, teams up with Isis to embark on a dangerous quest to get the artifact back and restore peace to the Egyptian godly realm.
Ra, the sun god. Maybe the story is about Ra losing his power to make the sun rise, and Percy has to help him get it back. This could involve a journey through different realms, with Percy using his wits and Ra using his remaining divine knowledge to solve the mystery of what has happened to his power.
The fanfiction might involve Percy being a guide for an Egyptian god who is new to the mortal world. Percy shows the god how things work in this world, and they get into all sorts of adventures together. For example, they could be trying to stop a dark force that is threatening to disrupt the balance between the mortal and divine realms. And during this journey, the Egyptian god might use his unique powers and Percy his own skills to overcome the obstacles.
Set, the Egyptian god of chaos. He could be a great antagonist as he might see the combination of Greek and Egyptian powers in Percy and the other demigods as a threat to his own plans of spreading chaos. He could try to manipulate events to turn the two groups against each other.
Zeus is a possibility. As the king of the gods, he might see Percy's potential and adopt him to have an ally among the demigods. Another could be Poseidon, since Percy is already his son in the original story. It would be an interesting twist to have Poseidon formally adopt Percy in a more divine way.
Percy would interact in a cautious yet curious way. He'd be curious about their powers, like Anubis' role in the afterlife. But he'd also be cautious as he doesn't know how they'll react to a Greek demigod. He might use his charm, which has worked on some Greek gods, to try and build relationships. However, he may face some resistance from the more xenophobic Egyptian gods who see him as an intruder.
Ra would be a likely candidate. He's one of the most important Egyptian gods, and his reaction to the fanfiction would be interesting. He might be offended if his power is misrepresented or amused if the writer has come up with a unique take on his role.
Percy would probably be initially cautious when interacting with Egyptian gods. For example, when meeting Ra, the sun god, Percy might be in awe but also a bit hesitant as their powers are so different. He would need to show respect as he does with the Greek gods. The Egyptian gods, in turn, might be curious about Percy's abilities, especially his control over water which is not as prominent in Egyptian mythology.
Another storyline might involve Percy getting lost in the Egyptian afterlife. He has to navigate through the different realms with the help of Egyptian gods such as Thoth, who is known for his wisdom. Along the way, he discovers secrets about the connection between the Greek and Egyptian pantheons. This could include how their powers are related and how the two mythologies might have influenced each other in ancient times.
In a fanfiction where Percy Jackson meets the Egyptian gods, it would be a clash of two mythologies. Percy's sword skills and ability to control water might not be as useful as he thinks against the Egyptian gods' unique powers. He could befriend some of the Egyptian gods who share similar values to the Greek gods he knows. However, he might also make enemies among those who see him as an outsider. The fanfic could explore how Percy uses his wits and his knowledge of Greek mythology to navigate the world of Egyptian gods and their associated creatures.
One idea could be Percy having to team up with an Egyptian demigod to stop a common enemy that is causing chaos in both Greek and Egyptian mythological realms. Maybe a powerful monster that is using the powers of both mythologies to grow stronger.
Well, without reading the specific fanfiction, it's hard to say exactly who Percy is. But generally, in a 'champion of the gods' scenario, Percy would be a central figure. He might be a hero with unique powers, like being able to control certain elements or having superhuman strength. He could be a character who has to face various challenges and tasks on behalf of the gods, kind of like a chosen one in a fantasy story.