Nightbringer | The Arthurian Online Encyclopedia

Duach

‘Black’

Son of Gwawrddur Hunchback, and brother of BrathachNerthach, and the lady Gwenwledyr.

He was one of King Arthur’s warriors. Duach and his brothers were “sprung from the Highlands of Hell“.


Source
Culhwch and Olwen | Late 11th century