Protagonist + Antagonist

Protagonist drives the plot forward.

Antagonist tries to stop him.

In the Story Mind, the Protagonist is the Prime Mover of the effort to achieve the Story's Goal. The Antagonist is the Chief Obstacle to that effort. In a sense, Protagonist is the irresistible force and Antagonist is the immovable object.

 The Protagonist represents our Initiative, the motivation to change the status quo. The Antagonist embodies our Reticence to change the status quo. These are perhaps our two most obvious human traits - the drive to alter our environment and the drive to keep things the way they are. That is likely why the Archetypes that represent them are usually the two most visible in a story.

Phillips, M.A,http://storymind.com/content/68.htm, (07.05.12)