Dark Guards
These are dwarfs who guard the Deep-Downers who rarely go above ground.
It's said that they take a slow poison before thy go on an important mission.
The Dark Guards in Thud! tried to invade Commander Vimes's house but unfortunately they came against his butler Willikins who dispatched most them with aplomb. One other Dark Guard flees in panic out of the nursery of Young Sam after seeing something resembling the mine sign of the Summoning Dark on the floor. But he mustered his courage again, and tried to flame Lady Sybil whilst she was in full Swamp dragon protective clothing when she was feeding the dragons. The swamp dragons, seeing the flame as challenge, answer with their own fire. The result is a black outline of the dwarf and two white-hot iron boots.
In Raising Steam, these are the bodyguards and enforcers of the Deep-Downers, who are first seen being used to menace and beat up threAnkh-Morporkian dwarf Magnus Magnusson in the streets of Bonk. They are next encountered as the muscle used by the ultra-conservative grags to impose traditional Dwarf values in Pant-y-Girdl, Llamedos. In this book they are called the Delvers.