Another possibility is that it's GoGo. The 11 years without someone could be a time when she has to reevaluate her role in the team and in the world. Maybe she was separated from a mentor or a close friend, and the fanfic details her journey to become even stronger and more independent during that long time apart.
It could be Hiro. Maybe he's been without Tadashi for 11 years in this fanfic, and it shows how he's grown up without his brother's physical presence but still holds onto his memories and ideals.
Baymax might be the main focus. Suppose he's been separated from the team for 11 years. The fanfic could explore how he's changed during that time, perhaps developing new programming or ways of thinking while being away from his friends in Big Hero 6.
Maybe Hiro. Since he's the main protagonist in Big Hero 6, it's possible that the story could revolve around him getting into an embarrassing wedgie situation. It could be used as a way to show his more human and vulnerable side among all the high - tech superhero stuff.
It could be about a character in Big Hero 6 who has been separated from someone important for 11 years. Maybe it's about how they've coped during that time, the changes they've gone through, and their journey to reunite.
It might be a commoner who has shown extraordinary abilities. The council, made up of the elite, might not want to give him a say in important matters and make decisions without his consent. This could then lead to a story of the commoner rising against the unjust council.
GoGo could be a main character. She's strong - willed and independent in the original Big Hero 6, and in a Yuri fanfic, she could be in a relationship or have strong emotional ties with another female character. Honey Lemon is also likely. She's kind and creative, and her personality would make her a great candidate for a Yuri - themed relationship. They could be exploring their feelings for each other in the fanfic.
James might be the main character. He's the vain one, so getting a wedgie would be especially humiliating for him. It could be a story about how he has to deal with his vanity after such an embarrassing incident, like trying to hide it from the fans while still being his flamboyant self.
It could be a child. A young kid who is always getting into trouble at school for being too curious. One day, while exploring an old attic in his school, he accidentally uncovers a map that leads to a hidden treasure. But this treasure is also the key to saving the school from being demolished. So, this naughty child becomes an accidental hero.
Maybe it's Captain America. He represents the moral compass of the group. In a sleeping fanfic, his dreams could be filled with memories of his old life and how he has adapted to the modern world. His sense of duty might even be present in his sleep, and he could be the one to wake up and check on the others if he senses danger.
It could be a mermaid or merman who is alone in the ocean for some reason, maybe banished from their community.
The main characters are Hiro and Baymax. There are also other friends in their team.
I'm not entirely sure as I haven't read this specific fanfic. But since it's a Naruto - related fanfic and mentions Ophis, it could be Naruto himself as the main character with Ophis having some sort of significant role in the story, perhaps as an ally or a source of power or conflict.