Black dwarves were a variety of dwarf. Though briefly mentioned, they were never described in The Edge Chronicles, until the book The Immortals.

In The Immortals, they are described as small beaked goblins, with talons on their feet. Their red skinned kin, the Red Dwarves, were in charge of maintaining the Thorn Gate, enslaving and abusing the Nameless Ones to trim the thorns. Presumably both red and black dwarves were extremely rare creatures as they were almost never encountered in the series.