The whole Douluo Dalu Universe is so vast that no one can measure how big the whole universe is. Therefore in the Universe, there are actually many existences like a God Realms, these higher-dimensional realms. But these realms are only a piece of the infinite amount of higher-dimensional parallel spaces that makes up the whole universe. These infinite higher-dimensional spaces is why the theory of multidimensional space exists in the Douluo Dalu Universe.
This is why different higher-spaces and star domains may give birth to their own God Realms. Making it possible for Gods with the same position to exist because they exist in other higher-dimensional spaces/God Realms. For example, it's possible for a God-King and a First Class God Sea God to exist with the same concept because they lived in another God Realm.
It should be know that First-Class Gods are beings that can the changes in higher-spaces and be able to shuttle between them. This is because the higher one climbs in dimensions, the more they can feel the Multidimensional Spaces.
Hence why the universe is divided into ten levels, with the higher ones grasping more of the Multidimensional space. Starting from 4-D spaces one can travel anywhere in the 3-D spaces and between the higher.
Then 5-D-space one can see the past and future of different parallel universes. Those in 6-D can see the past and future of any different parallel universes space-times. The creatures in the six-dimensional space can change time and space arbitrarily. Those in 7-D are connected by two infinite possibilities brought together. Those in 8-D space can travel in different multi-universes, with the rules in these multi-universes being different. In short, in each multi-universe, matter, nature, and chemical reaction rules are different. Those in the 8-D spaces are required to master and rule over all higher-dimensional universes leading to being the Master Of All Universes.
In 9-D, one is called the God Of Creation and can arbitrarily control the rules of the whole Douluo Dalu universe. They can change the Universe Rules such as gravity, time, speed, etc. at will. And the 10-D space holds infinite space-time, contains all the universe, all the possibilities, all the time, and all of everything. But touching this space will lead to the collapse of the Old multidimensional universe for the birth of a new one. And there also exist other Multidimensional Universes outside of the Douluo Dalu.
All of this fall under the Multidimensional Space Theory and is the origin of the entire Douluo Dalu universe.
The Universal Law is the origin of everything in the Douluo Dalu universe and also where everything originates from including the Multidimensional Space. It's beyond the normal 3-Dimensional universe of mortals with the Universal Law being abovethe rules of every multi-dimensional universe and with them being only parts of it. The Universal Law is formless, it cannot be seen or touched and it's consider an irreversible existence in the Douluo Dalu Universe and is what balances the entire universe. If something was to happend to the Universal Law then it will affect the life-span of the whole Douluo Dalu Universe and will lead to its collapse.
The Universal Law is hostile to all thing that it considereds a threat. Such as God Realms which accelerates the death of the Universe by adding more space into it. The Universal Law will destroy all God-Kings that is not in a God-Realm or with a position anchor to a God Realm. If one was to control the Universal Law they would be able to change the rules of all of the higher-dimensional universe across the whole Douluo Dalu Universe.