I don't know for sure as I haven't read it. But surely the mercenary girl herself is a main character. There might also be some classmates who play important roles, like a popular student who befriends her or a bully who challenges her. And there could be a teacher or two who notice her different behavior and try to understand her better.
Since it's a novel about a mercenary girl in school, the girl is the central character. There may be a male lead, perhaps a fellow student who is intrigued by her and tries to get to know her better. There could also be a group of friends she makes, each with their own personalities and backstories. Additionally, there might be an antagonist, like a jealous student or someone from her past in the mercenary world who follows her to school and causes trouble.
The main character is the mercenary girl without a doubt. In addition to her, there could be a best friend character who is very different from her, like a very studious and shy student who helps the mercenary girl with her academics. There might also be a school principal who has a strict attitude towards discipline and is initially suspicious of the girl because of her unusual behavior. And there could be a rival mercenary who also enrolls in the school for some mysterious reason, creating more drama in the story.
I'm not sure specifically as I haven't read it. But generally, it might be about a girl with a mercenary background experiencing school life. It could involve her using her unique skills from being a mercenary in the school setting, like dealing with bullies in a more combat - ready way or having a different perspective on friendship and competition compared to regular students.
The main character is definitely the girl who is known as the 'school prince'. She is likely to be surrounded by various characters. There could be a best friend who knows her secrets if she is hiding her true identity. Then there might be a group of students who look up to her as the 'prince'. And of course, there could be an antagonist, perhaps a student who is jealous of her popularity and tries to bring her down.
Well, obviously the main character is the girl who is disguised as a school hunk. She must be a complex character with the ability to act in a way that convinces others she's male.
I'm not sure specifically as I haven't read this particular novel in full. But usually, there would be the main mercenary character who is the focus of the story. There might also be a mentor figure, someone with more experience in the mercenary world who guides the main character. And then there could be comrades, other mercenaries who work alongside the main character on various missions.
Since I haven't read it, I can't say for sure. But likely there is the girl who is the 'prince'. There may also be her friends, who could be both male and female. And of course, there might be some love interests, like a boy who is attracted to her because of her unique charm as a 'prince' in high school.
Since I'm not familiar with the exact novel, common main characters in a mercenary - based story could be the broke mercenary himself, of course. There might also be a mentor - like figure, an old and experienced mercenary who gives advice. And then there could be a female character, perhaps a healer or another mercenary, who forms a relationship with the main character, be it friendship or something more.
Most likely, the main character is the invincible mercenary king. He might be accompanied by some interesting side characters. There could be a wise old mentor - type figure who has guided him in his mercenary career. And perhaps there are some rival mercenaries who constantly try to challenge his supremacy.
The girl herself is the central character. However, depending on the nature of the story, there could be other significant characters. If it's a story about revenge or getting back at someone who gave her a wedgie, there could be a character who helps her plan her revenge. Or if it's a story about growing up and learning from an embarrassing experience, her parents could be important characters as they might give her advice on how to handle such situations at school.
There could be detectives if it's a mystery - centered story. They would be main characters as they try to solve the case of the dead school girl. Also, any suspects in the story, like someone who had a conflict with her, might be main characters.
Since I don't know the exact 'School Girl Muscle Story', it's hard to say for sure. But likely, the main character would be the school girl herself. There might also be her friends, family members, or coaches who play important roles in her muscle - building journey.