The Threshold was discovered by Covu, who wandered space with the corpses of his wife and children in a strange and turbulent corner of uncharted space. He alone dared to enter, and returned only minutes later, but seemed years older and appeared stronger. He claimed his family was no longer dead, that they had risen and walked again in the 'verse on the far side of the Threshold, a glorious place he called "Underverse."
Covu returned to the Threshold with his successor Oltovm. It was an arduous journey, months long. Oltovm described the Threshold as, "Surrounded by great tidal forces of space, treacherous to navigate near, but exotically beautiful, hinting at the dark wonders that lurk beyond." Days were spent waiting for the tidal forces to ease, and then finally the Threshold opened.
Oltovm, intent on never losing his way to this remarkable place, erected hidden navigational markers that would lead him back. Never again would anyone doubt its existence. Once the way was charted, Oltovm initiated the construction of a portal around the Threshold, forces that could resist the vortices of space and force open the Threshold on demand. A trusted officer was tasked with guarding the Threshold against marauding races. His name was never recorded, so he is simply referred to herein as the Guardian of the Underverse. Said to be nearly three meters tall, the Guardian and his legion of faithful will repel any non-Necromonger who may make unauthorized approach to this most holy of places. During those times when the Threshold is opened to admit a Lord Marshal on pilgrimage, the Guardian and his warriors must turn their backs so as not to gaze upon the Underverse.