Hisceria

Hisceria was a colony and eventual city built by the Mynomeanian peoples supposedly by the 3rd Mynomeanian Empire, the dates of its establishment and desertion are unknown with no known survivors ever leaving the city after its raids and annexation by surface dwellers. It was largely known for its rich veins of iron which fueled the economy and war efforts of Mynomeania, these iron findings eventually led to hundreds and thousands of people coming to work and settle the area established the crown colony of Hisceria. The later half of the 3rd Mynomeanian Empire's reign saw many conflicts with surface dwellers despite residing deep into the world these people came with never before seen weapons which outmatched the iron weapons of Mynomeania and the largest battle in the region would be the Battle of Hisceria resulting in the large abandonment of the city and annexation, only soon after the Empire itself would dissolve into squabbling states until the Mynomeanians effectively disappeared altogether.