As legend states in Fire Emblem: Radiant Dawn and, vaguely, in Fire Emblem: Path of Radiance, the world was created by a sole goddess, Ashunera. However, out of desperation over the warring Zunanma, in an emotional burst she flooded the world, destroying everything within it, save the continent of Tellius. Realizing what she had done, she decided to part with her emotions, splitting herself into Yune, goddess of chaos and transformation, and Ashera, goddess of order. Ashera now summoned three heroes to seal away Yune: Dheginsea, the Black Dragon King, Soan, the Lion Warrior, who became the second king of Begnion, and Altina, who became the first Queen of Begnion and the mother of the first Branded. They succeeded and Yune was sealed within Lehran's Medallion; she was now dubbed as a "dark god" to prevent people from freeing her.
Though it was not much of a secret after the Part 4 endgame section 4 of Radiant Dawn, Prime Minister Sephiran, Duke of Persis, was actually Lehran, creator of the medallion, the thousand year old Heron, and the father of the first Branded. He was also said to be the representative of the bird tribes to Ashera. It is theorized that Lehran had inherited Altina's dual blades, Ragnell and Alondite, after she had died. About 650 years later, Lehran, now known as Sephiran, gave both swords and a blessed suit of heavy black armor to Zelgius of the Daein army, who later became the General of the Begnion Central Army.