The Dark Cathedral was a portal to the Darksmith Collective's lightless underworld home, beneath the surface of the planet Karagula. Few uninvited visitors survived, except those striking a deal with the Darksmiths themselves.

Inside the Dark Cathedral could be found a library of the Darksmith Collective, which housed the trading registers and contract details of those agreements undertaken by the Collective. Brother Varlos' journal on the Eternity Project was stored here in a secret room. (PROSE: The Colour of Darkness)