A knight slain by Sir Meliot of Logres.
Earlier, Gawain had cut off one of Gylbert’s hands during a duel. When Meliot killed Gylbert, Gylbert’s lover cast an enchantment on Meliot that left him with an incurable, festering wound. The wound could only be cured if some knight braved the adventure of the Chapel Perilous, retrieved a sword from within, and ran the sword over the wound. Lancelot completed the adventure and cured Meliot.
Source
Le Morte Darthur | Sir Thomas Malory, 1469-1470