Kardruin is the dark twin of Thardruin, the nation of the dwarves. Set deep within the southern Granite Mountains, the nation of Kardruin is the realm where duergar and derro make their primary homes, living out their respective lives, relatively close in distance, though not in temperament. The derro are largely dominated by the duergar in the depths, though they are too mad to be properly conquered, and so the duergar simply ensure that they do not interfere with the plans and work of the duergar, and allow them to do otherwise as they please, doing a brisk trade in magic items in the process.

Major Races: Duergar; derro; various slaves.

Government: Theocratic fascism.

Nation Alignment: Lawful Evil.

Major Cities
Deepfast: Major population center of the duergar, capitol of the region, center of mineral trade for a vast territory, both above and below.

Madhome: Derro-dominated city with a Chaotic Evil alignment. Set along a major travel path for invading armies from Godskar heading to the west side of the Granite Mountains. Manufactures magic items for drow and duergar nations.

Earthsight: A reclusive area, largely inhabited by deep-dwelling gnomes and expatriots from several other factions of the Underdark. This community is a peaceful one, and noted for being accepting of all, while giving marginal support to the duergar, who largely leave it alone in exchange for occasional tribute and favors, as well as access to Earthsight's most important feature. Earthsight gets its name from the earth weird that lives in a deep cave burrowed into the base of Council Tower, the only such cave in the entire structure. She is willing to answer one question per visitor for every decade of a visitor's life (thus, if someone visited her at the age of twenty-nine, that visitor would get two questions, and then a third if the visitor came back the next year). Naturally, this is of great value to longer-lived races, such as dwarfkin and elfkin. The earth weird also governs Earthsight in a loose fashion, resolving disputes brought before her, but otherwise letting the inhabitants of the community do as they wish.