The Black Road, the lair of Kabraxis, the Thief of Hope, is an uberlevel accessible by using Dark Portal after killing Buyard Cholik in the Chaos Sanctuary.
The Thief of Hope and the Banisher of Light is a demon lord summoned long ago by a very powerful Vizjerei magi. He used his intelligence and power to form his cult and rule the lands. People followed his philosophy; 'walked' the Black Road he created, and soon his power grew so much that even the Prime Evils feared him. Thus they imprisoned him within the portal he came from, between the Sanctuary and the Burning Hells. It is whispered, among his remaining followers, that there is a way to release him from his centuries-long prison...
Points of interest
Kabraxis is sealed inside the Pillar of Skulls at the centre of the Black Road. Once it is destroyed, Kabraxis will be released.
Spread around the dungeon, there are also 5 elemental seals, each of which corresponds with one element: Fire, Cold, Lightning, Magic and Physical. When one is destroyed, it will unseal an Ultra Elemental, along with some normal elementals. Each seal and all elementals are immune to all elements except for their own. On Destruction difficulty, each Ultra Elemental will drop a Great Gem when defeated, which can be transmuted with the Soul of Kabraxis, dropped by Kabraxis, to upgrade it.