The UnderWorld
From Ardrana
The UnderWorld is a system of interconnected underground passages that, it is rumored, spreads throughout the area beneath Lanad i'Sarois, if not all of Ardrana. It is home to many creatures, most notably Drow, Duergar, and Deep Gnomes, but also stranger beings such as cloakers, illithids and aboleth.
Though it has never been mapped in its entirety, it is known that there are several entrances to this throughout the Lanad. These include one in the Caves of Chaos (which leads to the ruined Dwarven city of Dekh), one in the wood south of Semmarch, one in the Dwarven mines beneath the Thair Mountains, one beneath an abandoned temple of Kuraliskar in the Ruisti Forest south of Nazivonema, and one north of Promise Junction in eastern Arin. There may also be one in the Camlekian Waste, uncovered by the collapsed tunnel dug by a purple worm, but that has not been confirmed.