The Sunkroot Warrens

A wild root-cave network in the dark beneath the Vale, upstream of Vel-Sathra's tamed terraces along the same Rootwater — no moot governs it, and the Kneeling Drowned keep company with worse things here.

Where Vel-Sathra fits its basalt terraces between the stone roots and calls it a city, the Sunkroot Warrens upstream stay exactly what the underdark is everywhere else: unlit, unmapped, and hostile to anyone who mistakes the Rootwater's tame reach for the whole of it. The Kneeling Drowned tend a flooded shrine here and have started keeping worse company than penitence.