Definitely Annabeth. In a high school setting, she could be the super - smart girl who helps Fem Percy with her studies while also being involved in the demigod stuff. Her strategic mind would be great for solving high school mysteries too.
Grover would be an interesting addition. He could be the shy, but loyal friend who always has Fem Percy's back. Maybe he's part of the school's environmental club and uses his nature - loving side to make the school a better place.
Definitely Pikachu. Pikachu is Ash's loyal partner and can add a lot of cute and funny moments in the high school setting. Another interesting character could be Misty. She could be the tough girl who has her own ideas about Pokémon training and often clashes with Ash in a friendly way. Gary Oak is also great. His rivalry with Ash can be taken to a new level in high school, competing not just in Pokémon battles but also in academics or popularity.
I think Tiana from 'The Princess and the Frog' would be a great character. She could be the hard - working student who is always trying to save up for college by working part - time jobs at the school cafeteria or library. She might also be part of a cooking club and compete in school - wide cooking contests. Another interesting character would be Hercules. He could be the star athlete in high school, but also a bit of a dork when it comes to academics. He would constantly be trying to balance his sports achievements with his need to study and fit in with the smart kids. And Maleficent could be the mysterious, feared teacher who has her own hidden agenda for the school.
Lizzie could be a popular cheerleader - type character. She's always trying to get Ciel's attention and is really good at sports. But she also has a bit of a temper when it comes to other girls getting too close to Ciel. And then there could be a new character, a shy transfer student who gets caught up in the drama between Ciel and the other students, and she has her own special abilities that she's not aware of at first.
One of the most interesting characters to include would be Hermione from Harry Potter. Her intelligence and knowledge of magic could help Percy and his friends in many situations. Also, Captain America from the Avengers. His leadership and sense of justice would blend well with Percy's own heroic nature. And Clary from the Mortal Instruments, her skills as a shadowhunter and Percy's demigod abilities could create a really engaging story.
Nico di Angelo is quite popular in these fanfictions. His dark and mysterious nature adds an exciting element. He might be the new kid at school who Percy has to befriend or protect. Also, some of the new characters created by fans for the high school setting can become popular. For example, a new demigod who has a unique power and becomes Percy's rival or ally in high school.
Grover would be a great addition. He could be the quirky sidekick in the high school setting, always getting into comical situations while also providing some sage advice to Annabeth and Percy based on his own experiences. For example, he could help Percy figure out how to ask Annabeth to the prom.
Grover could be a great addition. He could be the goofy but loyal friend who always gets caught in the middle of Percy and Annabeth's drama. For example, he might accidentally spill some secrets that cause more trouble between them. Another good character could be Clarisse. She could be the school bully who has a grudging respect for Percy and Annabeth but still tries to cause problems for them now and then.
Definitely Percy and Artemis themselves. Percy with his demigod powers and his ability to adapt to different situations is always interesting. Artemis, being a powerful goddess, adds a lot of depth and mystery. Also, including Chaos as a character can be really cool. It could be this all - powerful, enigmatic being that controls the very essence of disorder. Another interesting character could be one of Percy's friends like Grover. Grover's satyr abilities and his loyalty to Percy could play an interesting role in a story involving Chaos and Artemis.
Definitely Percy, as he is the center of the 'Remember Me' concept. But also, characters like Nico di Angelo could be really interesting. Nico has his own dark past and powers, and he could potentially use his abilities to try and reach into Percy's forgotten memories. Another interesting character would be Chiron. His wisdom and knowledge of the past could be crucial in finding a way to restore Percy's memory. And let's not forget Tyson, Percy's half - brother. His simple - minded but strong and loyal nature could bring some heart - warming moments as he tries to help Percy.
The teachers can be really interesting characters. There could be a really strict teacher at Edward High School who everyone is scared of, but deep down has a heart of gold. Or a young, hip teacher who the students all love and can relate to. And then there are the popular kids. They have their own dramas, like trying to maintain their status, deal with jealousy from others, and handle the pressure of always being in the spotlight.