Drudwas ab Tryffin
While he is listed as a follower of Arthur, one story tells how he was to meet Arthur in single combat. Drudwas' wife gave him three griffins, loyal and obedient creatures. He craftily told his pet griffins to go ahead and kill the first man who came to the field of combat, expecting it to be Arthur. However, Drudwas's sister was Arthur's mistress and she delayed her lover. Drudwas himself arrived first and the griffins, not recognizing him, killed him.
He was one of King Arthur's Three Golden-Tongued Knights of the Island of Britain, and his horse is listed as one of the Three Bestowed Horses of the Island of Britain.
Twenty-four Knights of Arthur's Court | The Legend of King Arthur
Adar Llwch Gwin | Myths and Legends
Griffins | Myths and Legends