The Underverse is a constellation of dark, new stars. The Necromonger Empire consider it their promised land; that only the Lord Marshals of the Necromongers are known to have journeyed to.
"In this verse... Life is antagonistic to the natural state. Here humans, in all their various races, are a spontaneous outbreak. An unguided mistake. Our purpose is to correct that mistake, because there is another verse. A verse where life is welcome, cherished. A ravishing evernew place called Underverse. But the road to that verse crosses over the Threshold ."