The Endless Void is said to drive all who gaze upon it mad. Only Yama and his secretive Dark Elves and other denizens of the deep places could tell you for sure, for only in the deepest parts of the Whorl can you find the hidden portals that gaze Outside.
It is said that the sheer immensity of infinite space, punctuated by the tiny pinpricks of light that are thought to be other Whorls, makes the viewer feel so small and insignificant that their sanity shatters and they can no longer be confident in the safety and security of seeming-natural laws.
Some such people become cultists of The Outsider, the mysterious god or entity that they believe fills all that dark space. For the vast majority of the inhabitants of the Whorl the Endless Void is just a story, a mythological flourish in the creation myths of the Whorl and nothing more.