Perhaps an ancient and dark deity who has been awakened due to some event related to Percy's exile. This deity wants to bring chaos to the world of gods and demigods, and Percy, even in exile, is the only one who can stop it. The deity would use all kinds of dark magic and minions to oppose Percy and his friends.
Maybe a rogue demigod who blames Percy for something and wants to make his exile permanent. This demigod could have some dark powers or be in league with some evil forces. They would constantly try to thwart Percy's attempts to return or find a way to clear his name.
One idea could be to explore Percy's life in exile and how he copes with being away from his friends and the world he knew. Maybe he discovers new powers or forms unexpected alliances. Another could be that he's exiled to a realm filled with ancient and forgotten creatures, and he has to find a way to survive and potentially return home.
One interesting plotline could be Percy trying to find a way to return home while facing new and unexpected challenges in his exile. He might encounter strange creatures or make new allies.
There could be a local guide in the place where Percy is exiled. This character could be an outcast from their own community and help Percy navigate the strange new land.
One idea could be Percy being exiled to a forgotten part of the mythological world, like a lost island where ancient and dangerous creatures lurk. He has to learn their ways to survive and find a way back to his friends.
He could be angry. Percy has always been loyal to the camp, and being exiled unjustly would make him furious. He might vow to prove his innocence and show the camp they made a big mistake.
In some fanfictions, he might be exiled because of false accusations. Maybe someone frames him for a crime he didn't commit, like stealing a powerful artifact from the camp's vault. The camp leaders, believing the false evidence, have no choice but to exile him.
One common theme is isolation. When Percy is exiled, he is cut off from his usual support system, so he has to deal with feelings of loneliness. Another theme is self - discovery. In exile, he often has time to reflect on who he is and what he wants.
A popular Percy exiled fanfiction is 'Percy in Exile: The Struggle for Survival'. It details Percy's day - to - day fight against the harsh elements and dangerous foes in the land of his exile. He discovers new allies and enemies alike, and the story is filled with intense action scenes. It also delves into Percy's internal thoughts as he copes with his situation of being exiled from his familiar world.