Which villain is Mario trying to stop in Super Paper Mario?

In Super Paper Mario, Mario is trying to stop Count Bleck. Bleck is the central antagonist who uses the Chaos Heart and the Dark Prognosticus to begin the destruction of the universe.

The adventure starts after Bleck abducts Princess Peach and Bowser and forces them into a marriage predicted by the Dark Prognosticus. Their union activates the Chaos Heart, which opens the Void, an expanding dimensional rift. Mario must gather the eight Pure Hearts to weaken Bleck and stop the apocalypse.

Dimentio is a major villain, but he initially serves Bleck as one of his minions. He later betrays Bleck, takes control of the Chaos Heart through Luigi, and becomes the final threat. Grodus belongs to Paper Mario: The Thousand-Year Door, while King Olly is the antagonist of Paper Mario: The Origami King. The commonly missed nuance is that Count Bleck is ultimately revealed to be Blumiere, a tragic figure whose plan grew from grief and despair.