- The World of Makai Ouji: Devils and Realist is not a "whole", "single" space.
- Previously, it contained many different worlds.
- "A long time ago …That’s right, a very long, long time ago. This world had many gods. And they each had their own worlds. You may not believe it but, the world was like the countless tree leaves that floated on a pond. I was one of the gods in one of the worlds of those small tree leaves."
- "This world is constructed in such a way. The world that has been separated will become one the instant God becomes one."
- "Thanks to the work of them primordial angels, Heaven began to gain power rapidly. They took in other gods, destroyed small worlds and absorbed them."
At first, the World was separated into many smaller worlds, each having their own Gods. At some point in the Past, Heaven started expanding and forcing others to Submit to their God,conquering other lands/Worlds ("swallowing them up" as Gilgamesh put it) and melding them into one.
- "Once there was a battle that was enough to tear Heaven and Earth apart. Lucifer, the Chief of the Seraphim and the Closest to God, he landed in the Inferno and revolted against Heaven."
A great battle happened (possibly the one between Lucifer and Michael) and split this single world, which was under the control of Heaven. Heaven and Earth were now two separate worlds, and whether Hell was created (separated) in this battle or existed before it remains unclear (Cassandra calls Hell "Lucifer's World" so the former is probable.)
- The World of the ancient Greeks, where the Greek Gods ruled.
- The World where Dantalion was one of the Gods.
- The World of ancient Mesopotamia (Sumeria), where Gilgamesh was one of the Gods.
- The World where Baal Zebub was the High God (God of Gods); Canaan.