“Ris of Outer Shadows”
King of Outre-Ombre who defeated nine kings and made a mantle for his paramour, the Queen of Iceland, out of their beards. He sent a message to Arthur’s court demanding Arthur’s beard. When Arthur refused, he besieged and captured the city of Cardigan.
He offered to grant any favor to a knight who would brave the fearsome Waste Chapel. When none of the knights rose to the task, Lady Lore of Cardigan – over Ris’s objections – completed the adventure and forced Ris to return her city. Later, Arthur’s Sir Meriadeuc defeated Ris and his best knights in combat, forcing them to surrender to Arthur. Ris reconciled with Arthur and became one of the king’s knights.
Found in the tale of Meriadeuc, his character and name were evidently suggested by Ryons.
Source
Meriadeuc or Le Chevalier aux Deux Épées | c. 1225-1250