The World of Ice & Fire (mentioned)|
The Sworn Sword (mentioned)
A Feast for Crows (mentioned)
Ser Gwayne fought during the First Blackfyre Rebellion, at the Battle of the Redgrass Field in Lord Donnel Arryn's vanguard. Lord Arryn's lines were shattered and nearly overrun by Daemon I Blackfyre, until Ser Gwayne appeared with reinforcements.
Ser Gwayne came across Daemon and the two dueled ahorsed for nearly an hour. The duel was considered a sight to behold, partly because of the clashing of two Valyrian steel swords against each other, with Gwayne wielding Lady Forlorn and Daemon with Blackfyre. Ultimately, Daemon cut through Ser Gwayne's helm and left him blind and bleeding. Daemon dismounted to ensure the wounded knight was not trampled and ordered Redtusk to bring Ser Gwayne to the maesters in the rear to see to his wounds.
A Feast for Crows