Well, it could be about Percy learning to survive in the wild using his demigod abilities in unique ways. Maybe he discovers new mythical creatures that are only found in the wild areas he's in.
In this fanfic, Percy might be raised in a really isolated wild area like a hidden valley. He would have to figure out how to get food, water, and shelter all on his own. His powers might develop differently, for example, his control over water could be related to the small streams and waterfalls in the wild. He could also face challenges from other mythical beings who see him as an intruder in their wild territory, and he has to use his wits and powers to survive and prove himself.
Obviously, Percy Jackson would be the main character. But there could also be some wild spirits or minor gods that take on a mentoring role for him, like a dryad who teaches him about the plants in the forest.
Well, it could be that Percy is raised by a specific god like Poseidon but in a more direct and involved way. Maybe the god teaches him all kinds of super - secret powers and knowledge that normal demigods don't get. For example, he might be taught how to control water in ways that are far beyond what he learned at Camp Half - Blood. This could lead to him having a whole new set of adventures, facing different kinds of monsters and challenges that are related to the god's domain.
Perhaps in this fanfic, Percy is raised as a sort of prince on Olympus. He could be given tasks by the gods to prove his worthiness to be among them. This might include going on quests that are not just for the safety of the mortal world, but also for the stability of Olympus itself. He would also have to navigate the complex social hierarchies among the various gods and goddesses.
Maybe Percy would grow up with the instincts of a tiger. He could be super fast and stealthy like them. And perhaps he'd have a special bond with the tigers that would help him in battles against monsters, just like how his demigod powers usually do.
One possible plot could be that Percy discovers he has a special connection with dragons. Maybe he finds out that the dragons sense his demigod powers and take him in as one of their own. He then learns dragon - related skills like flying on their backs or using dragon fire in battles against his usual foes in the Percy Jackson universe.
The fanfiction could start with Percy being lost at sea as a baby. Instead of being found by his normal family, he is taken in by a pod of dolphins or some other intelligent sea beings. As he grows, he learns to communicate with all sea life. He then discovers his demigod heritage but feels more at home in the sea. His adventures could include using his sea - based powers to fight against underwater villains who want to disrupt the balance of the ocean world, and he has to decide whether to stay in the sea or embrace his role on land.
Perhaps the monster is from a different pantheon and is raising Percy to bridge the gap between two different mythologies. Percy then has to deal with the cultural shock and the politics of two very different mythological worlds while being raised by this strange being.
Poseidon is a likely candidate. Since he is Percy's father in the original series, it would make sense for him to take a more active role in raising Percy. He could teach Percy all about the ocean, its secrets, and how to use his water - related powers more effectively.
One possible plot twist could be that Percy's wolf - raised nature gives him unique abilities. For example, he might have enhanced senses like super - hearing or smell. This could change the way he approaches battles in the Percy Jackson universe. Instead of relying solely on his demigod powers, he could use his wolf - like instincts to outwit his enemies.
Perhaps in the fanfic, Percy is a weapon in the sense that he is the key to activating a super - powerful ancient weapon. The gods and goddesses are all vying for control over him because they know that with Percy, they can wield this ultimate weapon. Percy has to navigate through political intrigue among the deities while also trying to figure out his own role in this whole mess.