Colgrevance of Gore
Colgrevaunce de Gorre, Galogrinans
Malory mentions "Sir Colgrevaunce de Gorre" as early as the battle of Bedegraine against the rebel kings, where he fights on Arthur's side. Malory notes that Bors, Lancelot, and others "had made promise to lodge with Sir Colgrevance" for a night. This knight of the Round Table had at least two deaths, both of them spectacular.
During the Grail Quest, Colgrevance happened to find Sir Lionel ready to slay his own brother Bors, who had earlier left him a suffering captive in order to go rescue a virgin. Colgrevance loved Bors and tried to stop Lionel. They fought long, but Lionel got the upper hand. Colgrevance cried out to Bors for help; Bors, however, was busy doing the Right Thing by refusing to raise a hand against his brother. So Lionel, who had already cut down a hermit for coming between him and Bors, slew Colgrevance. Colgrevance died with a prayer on his lips, and then, at last, with tears, Bors dressed to defend himself.
You can't keep a good man down, though. Colgrevance shows up again among the knights who try to heal Sir Urre, in Malory's story. Colgrevance of Gore was among the knights who went with Mordred and Agravaine to surprise Lancelot and Guenevere together. Lancelot was unarmed, and Colgrevance was the first to go into the Queen's chamber.
[Lancelot] unbarred the door, and with his left hand he held it open a little, so that but one man could come in at once; and so there came striding a good knight, a much man and large, and his name was Colgrevance of Gore.
Lancelot deflected his blow, killed him, and took his arms and armor. Colgrevance thus became the evening's first casualty. He might have been better off staying dead the first time; it was a more pious death and in a worthier cause. It is, of course, possible that the Colgrevance slain by Lionel was different from the Colgrevance of Gore slain by Lancelot - in which case there were two companions of the Round Table by that name. Some suggests Colgrevance and Calogrenat to be one and the same character.