The Cult of Nul is a quickly-expanding Underworld religion, with its appealing promise of reliable delivery from the miseries of consciousness. It has many local franchise temples throughout the Underworld, and maintains roadside Graven Images along major Underworld thoroughfares.
The Department of Cosmology at Omni-Cosmic University (go, fighting Pulsars!) seems to have an inordinate interest in the politics of a particular section of the Underworld in the impossibly remote Age of Swords and Sorcery.