A son of Nudd, thus sometimes bearing the patronymic ap (or ab, fab, mab) Nudd, a recurrent figure in several early Welsh narratives. In Culhwch ac Olwen Culhwch cites him as one of Arthur's warriors. In Breuddwyd Rhonabwy [The Dream of Rhonabwy] Edern leads the men of Denmark who are dressed in black. In Geraint ac Enid Edern contests with Geraint when his dwarf insults Arthur's wife, Gwenhwyfar. The Welsh Edern appears to be identical with the pseudo-saint Edern of Brittany, whose cult was once important in Finistère. R. S. Loomis (1927) speculated that the character of Edern may be the basis of such Arthurian figures as Isdernus, Ydier filz Nu, and Hiderus. Jean Markale (1986) has linked him with Yder de Northumbie in French Arthurian tradition.