nameless king

According to the lore of his armor, soul, and weapons, a dragon slaying god of war and heir of lightning that sacrificed everything to ally with the Ancient Dragons, taming a stormdrake who fought with him in countless battles.

Heavily implied to be Gwyn's Firstborn: a fearsome, dragon-slaying war god, founder of the Covenant of Sunlight and master of Ornstein, from the time of the ancient lords that had his deific status revoked and his name stripped from the Annals after an unnamed incident.