The Void is an interdimensional rift in Super Paper Mario. The purpose of it is to suck up all worlds in the game. It is purple and black in color, and grows larger and larger when Mario and Co. pass each chapter. Castle Bleck, Count Bleck's castle, is located in The Void. Each time that The Void grows larger, all of the worlds, Flipside, and Flopside, rumble and shake. The Void destroyed Chapter 6's world, with King Sammer and all of the 100 Sammer Guys, and destroyed the purple Pure Heart. However, Queen Jaydes, ruler of The Underwhere, was able to restore the purple Pure Heart. When Count Bleck became good again, and he and Tippi were reunited, The Void disappeared.
Although the word "the" in The Void's name is always capitalized in the game, on Super Paper Mario's website, Count Bleck called it "the Void".