Grover could also be in it. He has known Percy for a long time, and his reaction to Percy's new - found self would be interesting. Maybe he is initially skeptical but then comes to fully accept and support Percy's transformation.
Another possible character is a new antagonist. This new bad guy might be the catalyst for Percy's change, and the way Percy deals with this antagonist makes everyone see him differently. The new antagonist could also be used to contrast Percy's old and new selves.
There could be his friends like Annabeth. She might be the one who first notices Percy's change and helps others to see him in a new light as well.
There could be an old gardener who mentors Percy. The gardener might teach Percy all about the plants in the garden, their needs, and how to keep the garden thriving.
There could be other gods and goddesses. For example, Athena might be there to offer her wisdom to Percy as he navigates his new role. Poseidon, being Percy's father, could also play a part, maybe giving him advice on handling the power of a major god.
Well, without actually reading the fanfic, it's hard to say for sure. But it could be his friends. In many fanfics, there are often sidekicks or best friends who play important roles. They might support Percy in his adventures or add some comic relief to the story.
There could be new characters introduced as well. Maybe other gods or demigods who have a particular interest in Percy's new - found godhood. They could either be allies or antagonists, depending on their motives and how Percy's new power impacts the existing power balance in the fanfic's universe.
The fanfic might revolve around Percy going through a personal growth experience. He could have learned a valuable lesson that changed his perspective on life, and as a result, others start to see him in a new light. This new - found wisdom might make him more respected or admired by those around him.
There could be a rival within the family. Someone who wants Percy out of the way, perhaps for inheritance reasons or because they're jealous of Percy's abilities or popularity. This rival could be the one who instigates the events that lead to Percy's disownment. And then there might be a mentor - like figure outside of the family who takes Percy in after he's disowned and helps him to grow and face his new situation.
There could be his friends or comrades in the hunt. For instance, someone like Annabeth who might be affected by his leaving and try to convince him to stay.
There could be an alien sidekick named Zorx. Zorx might be a small, furry creature with the ability to see in multiple spectrums, which helps Percy navigate through different planetary environments.
Annabeth could be a main character. She might be initially distrustful of Percy because of his mother but then come to see his true worth. Another could be Grover, Percy's loyal friend, who stands by him through all the difficulties. There could also be new characters, like a half - spider half - human hybrid who is Percy's distant relative and helps him understand his heritage.
Annabeth could be a main character. She might be skeptical at first about Percy's new ability to control Styx, but then she uses her wisdom to help him understand the implications and possible uses of it. For example, she could research ancient texts to find out if there are any hidden dangers or benefits to Percy's control.