As the drows for the high-elves the duergars are the evil breed of dwarves. Living in the underdark for ages they grew fearsome warriors and gained knowledge of the mystic arts of this region. Duergars like mining and raiding as well, as they gain profit of both.
Dorston was founded above an adamantium mine in the south-eastern parts of the mountains, which the duergars mined up by now. But it is hidden well. It is said that the depleted mines now house a black dragon, ruling the other monsters that infest the shafts.
The town is wealthy by the standards of the underdark, but of course not measure with any drow standards. A fountain in the middle of the market- square is the center of the town. The speaker square can be found south of there.
Take care if you mess around with citizen of dorston, the guards might not let you out without paying for your crimes.