One of the original finders of the Souls of Lords, Gwyn ascended to become a deity known as the Lord of Sunlight. He and his loyal Knights fought alongside Nito, the Witch of Izalith and Seath the Scaleless to defeat the immortal Stone Dragons and usher in the Age of Fire, heralding the dawn of human civilization. Armed with the power of his Lord Soul, Gwyn used his Sunlight Spears to shear away the stone Scales of Immortality covering the Dragons so that they might be slain by his Knights and the other Lords.
Since the beginning of recorded history, Gwyn ruled over Lordran with his children Gwynevere and Gwyndolin, as well as a large number of other deities. Gwyn's first-born child, a powerful god of war, had long ago been stripped of his deity status and banished from Gwyn's presence due to his own negligence; now even his name is unknown.
As time passed, the First Flame began to fade, and with it the Lords' power. Before departing from Anor Londo, Gwyn split and bequeathed his own Lord Soul to his longtime confidant Seath and the Four Kings of New Londo. In an attempt to prevent the collapse of all life and preserve the Age of Fire against the encroaching Dark, Gwyn led his army of Black Knights to the Kiln of the First Flame and tried to rekindle the fire by using himself as fuel. Unfortunately his efforts failed, and with so little left of himself, the Hollowed Gwyn became the reclusive "Lord of Cinder" as the First Flame continued to fade.
Many of Gwyn's surviving Black Knights continue to stand vigil throughout Lordran, as well as his elite Four Knights: Ornstein, Ciaran, Artorias and Gough. Gwyn's Silver Knights guard the now-deserted Anor Londo, despite the gods' exodus from the city long ago.
Even after having given up much of his power as the Hollow Lord of Cinder, Gwyn is still a formidable force and wields a flaming Greatsword with ease. Fighting Gwyn requires mastery of Dark Souls' parry mechanic in order to avoid taking damage; otherwise, the player must endure the unblockable Fire damage dealt by Gwyn's constant attacks, or engage him at range. Due to his damage type, gear offering protection from Fire, such as the Black Knight Shield, is most effective for defense.