Griffon of the Treacherous Pass
The knight with the black armor of the Treacherous Pass.
He once lent Lancelot some armor, and later demanded Lancelot’s armor in repayment. Griffon rode around, displaying the armor, leading everyone to believe that Lancelot was dead.
He defeated and imprisoned Kay, but became scared when a body of Arthur’s knights set out after his head. He released Kay to Aglovale and stopped bothering Arthur.
See also
Maruc the Red | The Legend of King Arthur
Source
Vulgate Lancelot | 1215-1230