Ser Gwayne Corbray is an unseen character in Game of Thrones. He is long dead before the start of the series, and thus is not expected to appear. Ser Gwayne Corbray was a renowned knight of House Corbray and member of the Kingsguard under King Daeron II Targaryen.
In the books
In the A Song of Ice and Fire novels, Ser Gwayne Corbray's actions are recorded in the White Book. During the Battle of the Redgrass Field, he fought in the vanguard of Lord Arryn and dueled Daemon Blackfyre bearing Lady Forlorn, the Valyrian steel blade of House Corbray, while Daemon bore Blackfyre. Daemon defeated Ser Gwayne after an hour, but in a demonstration of chivalry, had his supporter, a knight known as Redtusk, take Ser Gwayne to the Blackfyre rear to see to his wounds.