Brannon Galathynius was the Fae King and founder of Terrasen, ancestor to Celaena Sardothien and Dorian Havilliard. Originally a bastard born in Wendlyn about thousand years before the beginning of the novels, he fought the Valg with Maeve in Wendlyn before emigrating West. Brannon was blessed with the gift of fire magic by the goddess Mala Fire-Bringer. His daughter, the half Fae Elena, founded House Havilliard with her mate, Gavin, after defeating Erawan a thousand years before the beginning of the novels.
In Empire of Storms, Brannon is described as handsome, with broad features and wearing ancient armour, having shoulder length red gold hair and "brandy" coloured eyes.
Little is known about Brannon's childhood, but it is known he grew up a bastard in Wendlyn before he caught the eye of Mala Fire-Bringer, who blessed him with the power to summon and manipulate fire. He was a formidable warrior, having fought the Valg with Maeve in Wendlyn before sailing west to Terrasen. Believing Maeve's intentions for the Wyrdkeys were far more dark than she let on, he took them with him along with the sacred Sun Stags from Mala's temple in Wendlyn, destroying it so no one could trace his footsteps. At some point, a temple sprung up around the rock he allegedly first stepped on when he reached Terrasen's coast in the ancient port city of Ilium.
More of his history is revealed in Empire of Storms, where his ghost makes an appearance to Aelin Galathynius after she takes back his temple in Ilium. He implores her to find the mysterious Lock in the Stone Marshes before vanishing. In Skull's Bay, the ghost of Elena Havilliard reveals that Mala Fire-Bringer was actually Brannon's mate, having forsaken her immortality to live a mortal life with him, bearing him several children, including Elena herself. She cast all of her life force and power into a Lock which Brannon forged to seal the Wyrdkeys into the Wyrdgate and banish Erawan and the other gods and goddesses to their home realm. Only Elena stole the Lock to seal Erawan in his dark tomb beneath Morath. The Lock then became known as the Eye of Elena, its true history lost to time. When she steps into the witch mirror made by Elena and Rhiannon Crochan, Aelin witnesses much of Brannon's history; Brannon sobbing over Elena's tomb, forging the Amulet of Orynth and concealing the first key inside and slipping the second into the crown of Elena's sarcophagus. He then takes the final Wyrdkey to Mala's temple, an island at the heart of a burning molten river, where he hides it beneath a flagstone, at last walking into the molten river, never to emerge again.