the character that forces the Main Character to face his personal problem
Every Main Character has a single Obstacle Character that forces him to face his personal problems. From the Main Character's point of view, the Obstacle Character may seem to be blocking the road to the solution of the Main Character's personal problem, or he may seem to be trying to knock the Main Character off the road to the solution. In a more objective view, the Obstacle Character functions to block the Main Character from sweeping his personal problem under the carpet, forcing the Main Character to address it directly. In every act, a story problem is introduced that requires the Main Character to expose his personal problem in order to solve the story problem. It is the Obstacle Character that creates the most personal tension for the Main Character. Frequently, the Main Character is chosen by the author to be the Protagonist as well, and often the Obstacle Character function is combined with the Guardian or the Contagonist. In this way, they each do double duty as prime movers of both the Objective and Subjective concerns of the story. This arrangement is not essential, however, and in many cases it is prudent to assign the Main and Obstacle Character roles to characters other than the Protagonist and Guardian/Contagonist in order to clearly explore the relationship between the Objective and Subjective problems of the story.