The Original Dimension, also known as the United World, is a dimension that became split into Four Dimensions.
A colorful and futuristic city, it has hovering vehicles and virtual birds while sharing many general similarities to the Fusion, Synchro, Xyz and Standard Dimension's architectural structures. It is also the birth place of the ARC System technology.
At some point, much of it was destroyed by Zarc using his fused Dragon form. At a later point, Ray Akaba opposed the Supreme Dragon King Zarc by using four cards to defeat him which caused them and the Dimension to split into four.