Saltdepth

Underneath the sprawling pile of habitation that is the city of Shellspinelies a far more orderly city, the Kobold stronghold of Saltdepth.
A labyrinth of interconnected tunnels, warrens and caverns that are nearly impenetrable to an outsider, the Kobolds who make their home here scuttle through them as one would the most open thoroughfare's on the surface. The construction is solid if a bit uninspired, enough to warrant a nod of approval from the best dwarven architect even as they found it a bit boring.
The city is ruled by a complex arrangement of hundreds of different clans with centuries of interwoven conflict, machinations and alliances. Each clan has sections of the city that are under their control with these sections shifting constantly, workshops and Nest Warrens being the most hotly contested spaces. These maneuverings rarely run into outright warfare however, it is considered very untrustworthy to openly spill blood in the city. The Kobold engineers have devised water driven apparatus to provide quick transport between sections of the city, several great lifts as well as small rail lines for industry and passengers.
The Kobold clans of the city have a close relationship with the city of Shellspine above, providing much of the infrastructural and engineering work needed to maintain the precarious structures there as well as forming the backbone of the Shellspine drydocks workforce.