The Slitherswamp
Located deep beneath the city of Waterdeep, the Slitherswamp is a largely unexplored sublevel between Levels Four and Five of Undermountain.
Halaster stocked the Slitherswamp with abductees from Najara in the Year of the Sighing Serpent (1289 DR), and it is still populated primarily by dark nagas, ophidians, and snakes of all sorts.
Contact between the Slitherswamp and Najara was not reestablished until the Year of the Serpent (1359 DR), when a dark naga dwelling in Under-mountain discovered a portal.
This particular portal linked the Slitherswamp with an area of rolling grasslands in the shadow of the Serpent Hills some 3 miles west of what is now Ithkyxan’s Lair.
More than half of the Slitherswamp’s inhabitants vanished via a second portal during Halaster’s Higharvestide in the Year of the Gauntlet (1369 DR).
This group is now imprisoned in the depths of the Nameless Dungeon in the High Forest, and no contact has been made to date.