The Monster Within is a duo RPG where players play a human dealing with their monster within. They must fight for control of their body or cooperate to survive.

One player will be the Human, a person tormented with a monster living in their body, an the other is the Monster, a creature eager to take control of the body to saciate its apetites.

This game brings rules to emphasizes the conflict between the two parts and the tension of losing the control in difficult times.