Underdark

The Underdark is an underground area in the world of Critical Role and in general RPG games such as Dungeons & Dragons. Many different, usually hostile creatures live there such as Duergar and Illithid.

During Vox Machina's travels in the Underdark, a series of rumbling noises would occur. They later learned from an Illithid named Clarota to keep still so as to avoid attracting unwanted attention.