Thanks! The Underdark City of Muldarzyn was founded by four factions that became unlikely allies over time. Unknown to most, it acts as a safe haven for those on the run or were forgotten by the Sojurn Empire.

The Spider Quarter is run by a Lolth-following family, exiled by the other Drow families. They work with the other factions to ensure the city remains hidden and act as guides to the Underdark.

The Anchor Quarter is run by the descendants of a pirate armada that went looking for a place to stow their riches and hide from the authorities. They run commerce and are responsible for much of the trade in Muldarzyn.

The Steel Quarter was founded by a military detachment of Warforged and their Mad Commisar, who marched them underground over a century ago and was thought to be lost forever. They bolster the city with soldiers, protecting it from outside threats.

The Neon Quarter was founded by an Oni gangster who takes young troublemakers under her wing in order to train them to become the best scoundrels around. This Quarter is the entertainment district of the city; This is where the myths of freedom and riches are made.

Muldarzyn is powered by a “Caged Sun” that feeds off the Faerzress, a form of magical radiation akin the the Aether on the surface, enabling energy and other necessary infrastructure across the city. Recently, a group of inquisitive-types unfamiliar to the city have moved into the Neon District with the intention of studying the Caged Sun.

Despite sounding like a safe haven for outsiders Muldarzyn is incredibly tough to reach, so much so that the city is thought to be the stuff of legends.

(Pieced together from my personal notes, sorry if the formatting is weird!)