Underdark

Category	Lexicon
Type	geographical lore

The Underdark represents the realm beneath a world's surface. Cartographers frequently subdivide it into distinct tiers, with Tier 1 denoting the area closest to the surface and subsequent tiers occupying lower depths. While the Underdark is sometimes referred to as the "Lightless Realm," this description is not entirely accurate. Vast stretches of darkness do exist, but the region also features expansive areas illuminated by the dull luminescence of subterranean organisms and vegetation. The forested regions of the Underdark are commonly known as Fungals.