Upon entering Dreamland Cave World, Yan Fei immediately severed the space channel to Dream Island, signifying that Dreamland Cave World was now completely isolated from the outside Universe.
Although Dreamland Cave World has a significant flow of personnel and materials within the Solar System, it does not actually reside in the Solar System, instead being at an infinitely distant location. Dreamland Cave World is not even within this Big Universe—it merely adheres to the Space Crystal Wall of the Big Universe, existing by virtue of the Big Universe itself. Without knowing the specific spatial coordinates of Dreamland Cave World, no matter how powerful a force may be, they cannot find the true location of Dreamland Cave World and naturally cannot pose any threat to those inside Dreamland Cave World.
