Located in the depths of the Northern Thrym Mountains, this Duergar city is closed to all outsiders. They do however, open a controlled exterior cavern where they sell their goods and charge outsiders to use two of their many mines.
The Bal’ynaz Duergar nation has maintained its isolationist doctrine for hundreds of years. In fact, the country of Markshire as a whole does not realize that there is a city beneath the mountains near the Pass. The leadership of Markshire has gone to great length to maintain a treaty of neutrality with Bal’ynaz. The fear is the dark dwarves have an army rivaling anything Markshire can muster and would use it if they felt sufficiently threatened.
The treaty is one of mutual defense against the frost giants and trade. The Duergar rival their cousins in craftsmanship and take magesmithing (magical crafting of arms, armor and more) to a higher level then even the elves. Some of their creations are sensitive to light since they only exist in the darkness of their caverns. They say that the truly powerful magical creations will lose their powers in the light of the sun or worse, explode.