The main character is Percy, no doubt. But don't forget about the other campers at Camp Half - Blood. They could be involved in different ways. Some might be worried about Percy and offer their support in small ways. Others could be a bit jealous of all the attention Percy is getting and cause some minor conflicts within the camp while Percy is sick. And of course, Percy's mom could also be a character. She might come to the camp to be with her sick son, adding an emotional touch to the story.
Obviously, Percy would be the main character as the story is about him getting sick. But his friends like Annabeth and Grover would also be important characters. They would be the ones trying to help Percy get better, so they play a big part in the fanfiction.
Obviously Percy would be one of the main characters as he is the one who is sick. His best friends like Annabeth and Grover would likely also be main characters as they would be taking care of him or trying to find a cure for his illness.
Joho is the main one for sure. But there could also be a love interest. Maybe someone who has always had feelings for Joho and uses this time when he's sick to get closer to him and show their care.
Obviously, Danny would be the main character since he's the one getting sick. His friends, Sam and Tucker, would also play important roles. They would likely be the ones trying to help Danny get better and keep his secret if he doesn't want it known.
Well, one possibility is that Percy's friends try to find a cure. Maybe Annabeth uses her wisdom to research in the library of Camp Half - Blood while Grover tries to use his nature - related powers to find some special herbs. And Percy is just lying in his cabin, feeling really weak and feverish.
Grover could also be a main character. He might be at the scene when Percy gets drunk and try to use his nature - related powers to sober Percy up. Grover could also provide some comical relief with his reactions to Percy's drunken state, like his horrified expressions or his attempts to herd Percy like he would a wild animal.
The main characters would surely include Percy. Then, there could be Tyson, Percy's half - brother. Tyson could be really worried about Percy and use his strength to protect him while he's sick. Also, Chiron in his disguised form as a teacher at the school could play a major role. He has a lot of knowledge about demigod illnesses and could guide Percy's friends on how to help him.
Definitely his family members. His mother, for example, would be a crucial supporting character. She would be worried sick about him and would do everything in her power to take care of him. His father might also play a role, perhaps using his godly powers in some way to ease Percy's suffering.
Sonic would be a likely main caregiver. He and Tails are very close friends. Sonic would use his speed to quickly get any medicine or supplies that Tails needs.
One of Tobirama's students, like Kakashi's father, Sakumo Hatake, could be a main character. He would be eager to prove himself by finding a way to heal his teacher. He could face many challenges and grow as a character throughout the process of trying to save Tobirama.
Even the kids who visit the pizzeria could be main characters. They might be the first to notice that Foxy is acting strange. One of the kids could be really attached to Foxy and be very worried about him. This kid could try to get the staff's attention to help Foxy or even try to comfort Foxy on their own.