Dark Sun Gwyndolin is the leader of the Blade of the Darkmoon covenant and the youngest of Lord Gwyn children in Dark Souls. He can be found in the lowest level of Anor Londo's moving spiral staircase and required the Darkmoon Seance Ring to reveal the hidden staircase by the bonfire.
Although male, Gwyndolin's association with the moon caused Lord Gwyn to raise him as a daughter. The last diety watching over Anor Londo, as his sister Gwynevere is only an illusion created by Gwyndolin himself, he is tasked with the execution of all sinners through his covenant.