In their ceaseless search for ores and minerals, Earthen, and particularly their miner genies, created numerous Underdark passages beneath the lands of Karnegmoth. Many of these passages are unused or forgotten, making them a haven for escaped slaves or wandering Underdark creatures. These tunnels, built in the name of Rilirthad, are collectively knowns as the Khans Passages; honoring the Dao Khan that have ruled Rilirthad.
The main tunnels vary in size from 20' to 40' wide. They are interconnected across many levels with smaller passages. The central axis begins at Tachylyte and then fans out in rings, connecting all of Rilirthad's major holdings.
In the Dao Civil War, the Khans's Passages were a chaotic maze of tunnels that led to many getting lost. The tunnels were also where much of the fighting occurred. The solidified bodies of dead dao can be found all over this area.
Today, parts of Khans's Passages are subterranean trade routes for the Rilirthad and the denizens of the Underdark. In the major trade lanes, the dao charge tolls which could be money that funnels back to the empire or feeds into some local Earthen gang. For many it is too difficult to the tell the difference between one serving the empire and one dressed to look the part, and not worth a fight to contest the toll.