Underdark

The vast cavern world beneath the surface.

The Underdark is a vast network of linked caverns and tunnels that stretches beneath whole continents in Dungeons & Dragons and forms an underworld for the surface settings. Polygon called it one of the game's best-known realms.

Lore & Background

Gary Gygax introduced the idea of a dungeon spanning a planet in his D-series modules, and Doug Niles described the Underdark in detail in the Dungeoneer's Survival Guide (1986). It is prominent in the World of Greyhawk and the Forgotten Realms, where much of its fame comes from R. A. Salvatore's Drizzt novels. Drow, mind flayers and aboleths live there among many other creatures, and its dangers include bad air, collapses and getting lost; apart from patches of glowing fungus there is no light. The Neverwinter Nights expansion Hordes of the Underdark is set there.