"The Mystery of The Fourth Void" 

People said that the place where domain clones were summoned was the fourth void, something in between the real world and the space crack. 

The real body of the domain would not exist in the fourth void at all because the fourth void was too 'small' to sustain such a complete dimension like domains. 

But to host domain clones, the fourth void was enough. 

People who used teleportation or any space-related abilities actually got in touch with the fourth void and not the real space crack because the space crack was like the path to find new worlds and new dimensions. 

The space crack opened the path for people from various worlds to leave their world and enter a brand new world, and most often, they had to venture the space crack first before entering a new world. 

This is also why, only people whose strength had already reached the ceiling of this world could leave safely.