Slitherswamp was the eighth level of Undermountain.


Originally a sublevel located beneath the Farm Level, it was a series of water-filled caves not physically connected to any other part of Undermountain.[2] Rather, it was connected by portals to the Serpent Hills and High Forest.[2] Flora, fauna, fresh air, heat in the summer and cold in the winter, all came through these portals.[2] Over time though, the water and organic materials that entered the sublevel turned the environment into a swamp.[2] Circa 1295 DR, Halaster Blackcloak brought hundreds of snakes and serpentine monsters into the swamp to experiment on.[2] Save for those creatures he took for his experiments, Halaster left the swamp and it's inhabitants alone, sealed in the sublevel.[2] A few dark naga located the portals and managed to escape, prompting Halaster to install ssvaklor guards over the portals.[3] However, in 1369 DR, a concerted effort by the sublevel's increasingly numerous residents broke through the defenses of the High Forest portal and fully half of the Slitherswamp's population escaped through it.[3] The remaining 30-odd nagas and around a dozen ssvaklors ruthlessly kept the population of serpentfolk relatively small and ruled over them.[3] In the following years, physical routes to the surrounding levels were cut, appeared, or formed, and the serpentfolk apparently built a collection of temples dedicated to evil yuan-ti gods. In 1491 DR however, the yuan-ti who worshiped at the temples were wiped out by a trio of spirit nagas.[1] In light of this event, Halaster brought in a bullywug tribe, known as the Blacktongues to take control of the Slitherswamp, and installed a cruel death slaad, whom he controlled, to govern them.[1]



The following ways could be used to leave Slitherswamp:


The Ssethian Scourges
These were three spirit nagas who once fought the yuan-ti on this level, eventually emerging victorious. The nagas maintained a stable of thralls, controlling them with a rod of rulership.[1]
The Blacktongues
Sent in by Halaster Blackcloak, this bullywug tribe acted quickly, enslaving four carrion crawlers and a hydra. The death slaad king's control gem was kept on level 9, Dweomercore, and Halaster Blackcloak forced the slaad to rule over the bullywugs.[1]
Karstis of Dweomercore
The mages on level 9, Dweomercore, had sent a spy of their own, a mage named Karstis.[6]