A new demigod who has a very different set of powers from Percy. This demigod could be from a previously unheard - of parentage among the gods. For example, a child of Hypnos, the god of sleep, who can put people into different levels of sleep - like a deep coma - like sleep or a trance - like state. This would add a new dynamic as Percy has to figure out how to work with someone with such a different power set.
Percy himself is obviously a must - include. His powers and his connection to Poseidon make him a central figure. Annabeth is also very popular. Her intelligence and her relationship with Percy add a lot of depth to the story. Grover is another great character. His loyalty and his role as a satyr can bring in some interesting elements, like his ability to sense danger and his connection to nature.
Definitely Thalia. Since she has a history with Percy and is a part of the Hunters of Artemis, she could bring a lot of drama and interesting interactions. Another character could be Reyna. Her strong - willed and leadership - like nature would make her a great addition to the group. And of course, some of the lesser - known hunters could be included, like Zoe Nightshade. Her backstory and her relationship with Artemis could add depth to the fanfiction.
A satyr who has a special connection to the minor god. He could be like Grover, but instead of being dedicated to Pan, he's dedicated to this minor god. He could help Percy understand the ways of the minor god and provide some comic relief as well.
Nico di Angelo could be a central character. Given his connection to the underworld and his own complex relationship with the gods, he might be the one who has the most knowledge about what really happened to Percy and how to reverse it. He could be on a quest to bring Percy back from the dead, facing many challenges along the way.
Annabeth could be one of the main characters. She might be torn between staying with the gods and following Percy. Their relationship could be a central part of the story as she tries to convince him to stay or decides to go with him.
One interesting character to include would be a half - blood from the Ares cabin who has the power to control fire, named Ember. She could be both a friend and a rival to Percy. There could also be a centaur who is a bit of an outcast from the main centaur group and teams up with Percy. His unique perspective and skills could be very useful. And then there's Rachel Elizabeth Dare. Her ability to see through the Mist and her non - half - blood status could bring a fresh dynamic to the story, especially when it comes to Percy's new situation as the 'Son of Ares'.
One idea could be Percy having to face a new and powerful enemy that even the other gods are afraid of. He has to use his unique skills and connections to defeat it.
He might introduce new relationships among the gods. Maybe a forbidden love between a god of the sun and a goddess of the night, which would create a lot of drama and conflict. This could lead to power struggles and changes in the divine hierarchy. He could also create new backstories for the gods, like a god who was once a mortal and achieved divinity through an extraordinary act of kindness.
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.
Another character that could be included is Clarisse. Her tough - as - nails attitude could contrast with the niece's, and they could start off as rivals but eventually become friends. Also, Tyson, Percy's cyclops half - brother. He could be like a big, protective figure for the niece, and his unique abilities could come in handy during adventures or when the niece is in danger.