From PathfinderWiki

Undermarket is a name given to the various underground layers that stretch beneath the entirety of the city of Goka as well as much of Xu Hong Bay. The Undermarket consists of many different layers from various eras and only one rule holds true for all of them: the deeper you go, the more dangerous it gets. The uppermost layers are populated by ne'er-do-wells, thieves, and thugs; while below those layers, lies a warren of catacombs, dangerous vaults, and forgotten temples dedicated to dark deities. At its lowest point, the Undermarket connects with the Darklands in what becomes known as the Deepmarket.1


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  1. James Jacobs, et al. “Regions of the Dragon Empires” in Dragon Empires Gazetteer, 16. Paizo Inc., 2011