Dramatica does not allow for more than one Main Character in a story. By Main Character, we are referring to the character through whose eyes the audience experiences the story, the very personal, “in the trenches” point of view. This is not the same thing as a Protagonist, nor the same as a principle or primary character, nor the “player” that these characters are played by. Very few stories have multiple Main Characters within a single story. Usually, when there is more than one Main Character, there is more than one story going on. If that is the case in your story, then you will want to create a different storyform for each Main Character. Stories that have multiple Main Characters work because the MC’s share exactly the same world view and they “hand off” the role back and forth. This is quite difficult to do—principally because the audience is unaccustomed to “body hopping” in their normal experiences.
The terms Antagonist, Protagonist, Main Character, and Impact Character have a very specific meaning in Dramatica. The Antagonist and Protagonist are part of what we call the Objective Characters which represent various approaches to problem solving in the Objective Story throughline (the “big picture”). The Main Character and the Impact Character are participants in the Relationship Story throughline and are identified by their points of view, not their functions. These objective and subjective characters are put into “players,” be they human or otherwise. For example, the “player” Luke in Star Wars is both the Protagonist and the Main Character. He functions as both the prime mover in the Objective Story throughline (trying to blow up the Death Star) and the personal point of view in the Relationship Story throughline (training to be a Jedi Knight). This is different from the way most story theorists approach story.