King Bowser Koopa is the main antagonist of the Mario series, the supreme leader of the Koopa Troopas, and the arch-nemesis of Mario. He has repeatedly kidnapped or attempted to kidnap Princess Peach and take over the Mushroom Kingdom. He has on other occasions attempted to conquer the entire Mushroom World, as well as the entire universe. Since his debut, Bowser has been in nearly every Mario game, including the main series, spin-offs, and crossovers. Besides being a primary villain, Bowser has at times played an anti-villain in several Mario RPGs, with the exception of Paper Mario.

It appears that Bowser has gone even further corrupt than in the past this time, and the crew of Gongshow:Gaiden has embarked on a quest to find what caused his craziness. Information known to the party: Has cannabalized and genocided the koopas. Is supposedly 80 feet tall. Has had a recent personality shift.