They are eager to break out of the inner world and enter the surface world for a few days of joy.
However, they must wait for an opportunity to arise.
If the bizarre entities were to forcibly enter the surface world, they would be instantly assimilated by the rules of the surface world, eventually vanishing without a trace.
Conversely, when the surface world forcibly enters the inner world, there is no effect whatsoever.
The two worlds have maintained each other for so long, it has become very difficult for them to continue existing.
One of the worlds is bound to completely collapse, while the other will gain tremendous benefits.
Thus, the bizarre entities' goal in rushing out from the inner world to wreak havoc is to shatter the surface world, allowing greater changes in the inner world.
