Dafyll ap Gwydion was the first High King of the North American sidhe and leader of their armies during the Accordance War. He wielded the magic blade Caliburn from the moment he returned with the Resurgence until his death in 1973 in the Battle of Manhattan. He was succeeded by David Ardry.
Lord Dafyll's death has frequently been blamed on commoner spies within his own retinue, including the sluagh anarchist Doctor Coma. However, he was actually betrayed by his own fosterling, Alexandria ap Fiona, who had her lover Rat Breath murder him in the confusion of battle.