"In the shadow of a dormant volcano crouched the dead city of Sumara. Wandering necromancers rediscovered it in the wake of the Divine War, and from the bones of that slain nation, the wizards fashioned a new realm: Hollowfaust, City of the Necromancers. Today, this city-state grows and prospers, defended by legions of undead warriors and ruled by a secret society of powerful spellcasters. On the surface, there exists a curious culture that embraces both the joy of life and the inevitability of death, but deep below, in tunnels beneath the city, the necromancers delve into the secrets of mortality and the undead. Welcome, then, to Hollowfaust — one of the strangest cities in all of Ghelspad. Enjoy your visit. And don’t die."
- – Official sourcebook blurb
Hollowfaust is a city-state in the Scarred Lands setting of Dungeons & Dragons that is run by a magocracy made up exclusively of non-evil necromancers. Despite the terrible reputation that this gives it, Hollowfaust is actually one of the nicest places to live in all of the Scarred Lands. The necromancers don't really care for mundane taxes, and a side-effect of their studies (and their reliance on a military/labor force made up of skeletal undead) means it has one of the highest understandings of health, medicine and public hygiene in the world - for the simple price of submitting to the rule of the necromancers (who actually don't care about the messy business of day-to-day operations and generally leave their rules at "the bodies of your dead belong to us" and "we're in charge, so don't try to rebel"), its residents enjoy one of the highest standards of living anywhere in all the world.
It had its own dedicated sourcebook: "Hollowfaust: City of Necromancers".
The religiously inspired portions of Hollowfaust's culture center around the psychopompic death deity Nemorga. Nemorga's iconography commonly depicts him wearing a mask, and Hollowfaust's most spirited holiday is its Carnival of Masks, originated in honor to it's mask-wearing deity. Modest shrines to other deities can also be found in Hollowfaust.