How to know if the MC is the protagonist or not
Question: I have a main character, who is the brother of the antagonist, who is the leader of the city. The story is about the rebellion leader, who tries to show the main character, how things truly are in the city. For example, how people are dying, the huge difference between the poor and the rich.
The Main Character realizes more and more, that he is wrong, but isn't sure about who he can trust. The rebellion leader wants to use him to end the conflict in the city, but the main character is reluctant. Is he the protagonist, or is the rebellion leader the protagonist?Answer:
The antagonist's brother is the main character if the story is told primarily from his point of view, and if his decision at the climax determines the outcome.
At the same time, it sounds as though your rebellion leader is both protagonist and impact character.
This is assuming, of course, that the main character is not the primary character driven to pursue the story goal or consider its importance. (Pursue and consider are the defining traits of a protagonist.)
There are also times when the functions of pursue and consider can be split between characters, creating non-archetypal character roles.
For instance, you could have the rebel pursuing the goal of deposing the current leader, but have the main character be the one who considers or gets others to consider the need to achieve it.
Or you could have your rebel argue for the need to depose the leader (consider), and then have your main character lead the charge (pursue).
To not give your main character the pursue function will make him seem a little more passive. But there is no reason why he cannot take on one of the other archetypal roles (sidekick, skeptic, guardian, contagonist, reason, or emotion).
Sometimes it is more interesting to tell a story from the point of view of someone other than the protagonist, particularly if you want to give your main character a moral dilemma (as it seems you do), and make the story more of a dilemma/decision story than an action story.