Our original intent was to view the OC as an obstacle preventing the MC from hiding from his personal issues. We revised the label to IMPACT Character to make the IC/OC more active than the seemingly passive "obstacle" to be circumvented.
Just to make your lives even more complicated, we're introducing a third interpretation of this character's label in the next version of Dramatica: the Influence Character. We feel it strikes a nice balance between the indirectness of an obstacle and the directness of an impact.
In point of fact, they are ALL equally valid interpretations of the purpose for having a character representing or proselytizing an alternative viewpoint to that of the MC in the MC's approach to resolving his personal issues. Active or passive, aware or unaware, the obstacle/impact/influence character represents an alternative paradigm to that of the main character.