In the fanfiction, Percy might meet a mysterious new student who seems to have some knowledge about the demigod world. This student could be a potential ally or a new threat. Or he could meet an old acquaintance from the demigod realm who has also found their way to Goode for some reason. This encounter could lead to a whole new set of adventures and challenges for Percy.
He could meet his old teachers again. They might be surprised to see him back after his long absence.
There's a chance he'll run into some of his former classmates. Maybe some of them have changed a lot, and it'll be an interesting reunion. Also, new students could be introduced in the fanfiction, and Percy might interact with them, either becoming friends or getting into some sort of conflict.
He might meet his former classmates who have changed a lot since he left. Maybe some new students who are intrigued by his reputation.
There's a good chance he'll meet the goddess Athena. Since Percy has a connection to the world of the gods, and Athena is known for her wisdom and strategic thinking, she could offer Percy some valuable advice. Maybe she'd help him navigate the complex social and political situations in ancient Greece or teach him some new ways to use his demigod powers.
He could meet some of the older campers who usually don't interact with the new arrivals right away. They might give him some special advice or warnings about the camp.
He might meet alternate versions of his family members. Maybe a Percy from another universe whose mother is a powerful queen instead of a mortal.
He might meet Luke before he turned bad. Percy could try to change Luke's fate, convince him not to follow Kronos. It would be a great chance to save a friend and prevent a lot of the chaos that happened later.
He could also meet some minor nymphs or spirits that inhabit the island. These beings might be curious about Percy's return and have their own stories to tell. For instance, there could be a water nymph who has some knowledge about a prophecy related to Percy and his return to Ogygia. Or a spirit that has been observing the changes in Ogygia since Percy last left and can give him some insights on what has been going on in his absence.
Percy might meet an old enemy who has somehow been resurrected or changed in the future. This enemy could be more powerful and have a new plan to take over the world or destroy the demigods. Or he could meet a group of time - traveling demigods from an even further future who are trying to fix something in Percy's future that has gone wrong.
Perhaps Percy goes back to Goode to find a sense of normalcy. He might try to participate in school activities like sports or clubs. However, his past as a demigod will surely follow him. His powers could accidentally surface during a school event, causing chaos and confusion among his classmates. He'd then have to figure out how to cover it up while also protecting those around him from any potential danger.
Percy might run into Loki. Loki is known for his trickery. He could either befriend Percy for his own devious plans or try to deceive him. Percy, being used to dealing with tricky situations in his own world, would have to be on his guard against Loki's schemes.
He might meet a new teacher who is secretly a minor god or goddess in disguise.