A knight from Carlisle or Tabriol.
On Erec’s third day of adventuring with his wife to prove his prowess, they met Sir Cadoc’s lady weeping because two giants had just captured her lover. Erec gave pursuit and found Cadoc, naked, bound, and perched on a nag, his captors beating him with scourges until the blood ran.
Erec challenged, battled, and killed both giants, armed though they were with great, iron-shod clubs. Then he gave the grateful Cadoc back to his lady, requesting them to take the story to King Arthur, which they did. If the usual pattern holds, Cadoc and his lady would have joined Arthur’s court.
He is called Kalviel in the Norse Erex Saga.
Source
Erec | Chrétien de Troyes, late 12th century