Duergar

From LSWiki

Duergar:

The duergar are the grey cousins of the dwarves who dwell deep within the depths of the earth, where they compete for food and living space with drow, svirfneblin, and other less-savory races. They speak the Kathdax tongue, derived from the ancient Dethek spoken before the dwarf and duergar races divided. There is considerable enmity between the races in these times; most consider this to be a result of the more vicious, less honorable culture the duergar have developed over the centuries.

What is more curious is that some pressure of their aforementioned environment seems to have awakened in the duergar, alike with the svirfneblin, peculiar powers of the mind, and rare is the duergar who does not develop at least one esoteric psychic capability in his lifetime.

These "grey dwarves", as they are sometimes called, usually live for at least 250 years. Their vision is superbly adapted to lightless subterranean environments, but suffers significantly in light.