Dark Dwarf Miners are short but large creatures with large white beards, bright, red eyes, and rugged faces that look similar to the faceplates of samurai armour. They are dressed in simple and warm, brown attire, with a red cloak on top, and wield simple pickaxes, which they use as their weapon of choice.
On June 22, 2023, a large amount of Dark Dwarf Miners spawned in a hidden room in the 27th Floor Labyrinth, after Ducker triggered a treasure box trap that sealed off the area, prevented the use of crystals and continuously drew monsters to the area. With the help of Mineral Elementals, who were also summoned to the room by the trap, the dwarves slaughtered four out of six of the Moonlit Black Cats members: Ducker, Tetsuo, Sasamaru and Sachi. The last surviving member in the room, Kirito, managed to defeat a large number of them and disable the trap without being killed.