A demigod with the power to control time in a very limited way. For example, they can slow down time for a few seconds during a battle, which could be a very interesting addition to the story. They could be an ally or an antagonist depending on their motives.
You could have a character like Marie, a young demigod with the power to control the wind. She grew up in New Orleans and knows all the secret alleyways and hidden places in the city. Another could be Jacques, an old Cajun fisherman who is secretly a protector of a magical spring near the bayou and has some knowledge of the ancient Greek magic that Percy is familiar with. And then there's Lila, a voodoo priestess - in - training who teams up with Percy to fight against a common enemy.
There could be a satyr who is an amazing inventor. He creates all kinds of gadgets to help the demigods in their quests. For example, he might make a device that can detect monsters from a long distance or a shield that can adapt to different types of attacks. He could be a bit of a comic relief but also a valuable asset to the team.
An ancient demigod who was frozen in time and now awakens in the modern Percy Jackson world. This character has archaic ways of thinking and fighting but also has knowledge of long - forgotten prophecies and secrets that could either help or hinder Percy. They might have a different view on the gods and their roles compared to the modern demigods. For instance, they could believe in more direct worship and obedience, which would clash with Percy's more laid - back attitude towards the gods.
You could add a new demigod character. Maybe a child of Hecate who can use magic in interesting ways around the school. For example, she could make the lockers disappear or change the school cafeteria into a magical forest for a short time. Another character could be a satyr who is pretending to be a normal student but is really there to protect the demigod students. He could be the one who always seems to be eating strange things from his backpack, like enchanted herbs.
A shape - shifting creature that can take on the form of any animal. It starts off as an enemy, trying to steal something important from Percy and the Wanderer, but later realizes they are on the same side and becomes an ally. This character could bring a lot of action and mystery to the fanfiction.
A character like a time - traveling demigod from the future could be really interesting. This character could have knowledge of events that are yet to happen in Percy's world and could either help or hinder him depending on their motives.
A new character could be a mortal who has somehow gained the ability to see through the Mist completely. This mortal is on a mission to expose the world of demigods and the gods themselves. Percy has to either convince this mortal to keep quiet or find a way to make them forget what they've seen, all while dealing with the chaos this person is causing in the demigod world.
A Venator wizard who can manipulate time could be an interesting addition. He could help Percy in his quests by using his time - manipulation powers to gain an advantage. Another could be a half - Venator, half - demigod character who is conflicted about which world to side with.
Well, for the fanfiction, we could add a character who is a demigod of the moon. This demigod would have powers related to the tides, lunar cycles, and could even use moonlight as a weapon or for healing. They would bring a different kind of magic to the group. Another unique addition could be a half - human, half - centaur who is an expert in ancient languages and prophecies. He could help the seven demigods decipher old texts that are crucial to their quests. And then there's the idea of a demigod daughter of Hephaestus who can create living machines. These machines could assist the demigods in battles or in solving puzzles.
Another great addition could be Circe. She has a lot of knowledge about magic and the supernatural. In the fanfiction, she could be an ally or an enemy. If she's an ally, she could teach Percy and Artemis some spells to combat the chaos - influenced threats. If she's an enemy, she could be working with the forces of chaos to try and gain more power.