The Great Net

The Great Net. The Shield of Heaven. The Cage of Reality.
This phenomenon goes by many names, some positive, kind words speaking to its protective nature, while others are negative, speech laced with venom at its oppressive presence.
Regardless of what may be considered, there is one truth. The Great Net prevents those who enter Refuge from leaving it easily.
While the mechanisms for the exact nature of this are unknown, sufficiently advanced people and civilizations have been able to conclude that this metaphysical net is the reason why the many bits and pieces of All-Existence are able to be captured into the infinite plane that is Refuge.
However, what is the Great Net catching everything for? What lies beyond the many infinite realities that make up the All-Existence?
The answer to this is little known, even to the divine, who themselves are fragments of the greater concepts, about what lies on the other side of The Great Net. 
Yet, to those who perceive just right. The answer is obvious.
The All-Nothing.
That is what Refuge, for all its inescapable frustrations, acts as a shield against. It and The Great Net are a bubble wrapped around all of reality preventing anything from leaving and thus being utterly destroyed. It is the final layer. The catcher of all the fragments of the universe. The last separation between All-Existence and that which it once was.
While it is not known how this came to be, whether this is a natural phenomenon or a constructed one, what is known is that it simply is. And it does not let anyone or anything pass it easily.

Manifestation

The Great Net does not manifest physically in the space above Refuge's many regions. Instead, it is a presence felt by those who choose to go high into the sky. A building pressure that prevents them from being able to go beyond and into the stars.
To those who teleport, use portals, or any number of other means to try and leave Refuge. it is simply static. A lost connection to the worlds beyond Refuge.
That said, while it is not impossible to slip through The Great Net, methods to do so are rarely able to work long or consistently. A doorway past in the present is inevitably locked in the future. And those who slip past, are unlikely, if ever, able to return.

Type

Metaphysical