From the Dramatica Theory Book:
In The Elements of Structure: Foundations we described four throughlines in a story – the Objective Story Throughline, Main Character Throughline, Obstacle Character Throughline, and Subjective Story Throughline. The Objective Story Throughline describes the relative value of the approaches of the Objective Characters. The Main Character Throughline describes the point of view and growth of the Main Character. The Obstacle Character Throughline describes the alternative point of view and growing impact of the Obstacle Character, and the Subjective Story Throughline describes the ongoing argument between the Main and Obstacle Characters as to whether the Main character should change or not.
A good way to think of these four throughlines is as four different points of view through which the audience relates to the Story Mind — the same four points of view we all use in all of our relationships. The Main Character represents the “I” point of view. The Obstacle Character represents the “you” perspective. The Subjective Story Throughline covers the “we” perspective, and the Objective Story Throughline explores the “they” perspective. Taken together, the four points of view range from the most personal to the most impersonal, and provide all of the angles we use to examine the nature of our problems and the relative value of alternative solutions.
We have previously looked at the Elements of Character from a purely objective perspective. When we stand in the shoes of a character, however, we get an entirely different perspective. Rather than seeing how the events of a story relate to one another, we become more concerned with how events effect us personally. Providing this experience is the purpose of the Main Character.