The Krephus Passage was created in the Dawn Era. It was created when a colossal primordial worm named Krephus escaped the Step of Foundation. Aftering boring its way through the Web of Magic, it found itself on another world. On Bal-Kriav's continent Hezmort, it dug down, leaving behind the great bore hole named after it, the Krephus Sink. In her wake, Krephus left a wide cylinder passage that crosses many continents, dives into the Underdark beneath oceans, ending in the Underdark region Badmaer where she died.
At its northern tip in the Badmaer region, where the passage joins with the cavern complex Vogelak, is where Krephus breathed her last. The last 900' of this tunnel, roughly 60' across, is the petrified body of Krephus. Upon her death, a spell was triggered that magically petrified her body (put on her by Hon'palos). Krephus's body became stone as hard as any diamond. Foreigners entering this northern tract of the Krephus Passage often don't even realize their traveling through the body of a petrified primordial purple worm.
. In the great caverns beyond, they rebuilt their civilization. In the early part of the Horgon Era this area and Vogelak had become territory of the gnome kingdom Isan-Kun. The gnomes of this kingdom consider this area to be sacred, for it was here that a long journey ended, one that took them from one continent, across the great deep Underdark beneath the ocean Morwuld Brinn, and then to Brucrumu's Underdark. Before Isan-Kun was founded by the Vogelak city-states, the gnomes did not always have the strength to protect the area. As a result, foes like the goliath, frost giants, and Azwyr Amoruk mined the Krephus Passage without regard to its sacred status to the gnomes. The pieces taken from the place though hard as diamond were as light as oak; these chunks of the petrified worm are often called Krephus Plates. They have been used to make armor and weapons of great strength and durability.