Dimension D was a world created by Dimentio in Super Paper Mario. It made everyone stronger, but in Into the Fourth Dimension, Dimentio used this place to survive and made it so that only he will get stronger in it and synced it with the Fourth Dimension through the Dimensional Gateway. Princess Kiwi was captured and trapped in Dimension D with many other citizens of the Fourth Dimension. When the heroes arrived at Dimentio's Lair, Dimentio threatened Quario that he would kill her if they don't give him the D-Stars. The heroes later used this place against him and evacuated this dimension so they can un-sync and destroy it, destroying Dimentio. It made everyone over 256 times stronger, but Dimentio made it so only it would give him over 256 times more powerful. After Dimentio's defeat in INt4D, Dimension D was destroyed.