With a compelling original story based on the theme of battle against darkness that revolves around the lost kingdom, Majin creates a new fusion of stealth and action adventure as the player takes the role of the game's hero to fight alongside the AI-controlled monster Majin and overcome the obstacles and adversaries in their path. They pursue their individual objectives while fighting against darkness which brings them strong friendship, and the secrets around the lost kingdom and Majin unfold as the story continues.