In the Post-Vulgate Mort Artu, a knight who hated Lancelot, and who participated in Agravain’s plot to expose Lancelot’s affair with Guenevere. He was in the group of knights that surprised Lancelot in the Queen’s chamber, and was the first to fall under Lancelot’s blade.
In Malory, this knight is Calogrenant.
Source
Post-Vulgate Mort Artu | 1230-1240