The World Was Broken.
Shattered. No one knows exactly how; all we know is that eons ago, the Veil was pierced. They say the Veil was the only border between our world and a stranger, more magical world Beyond. Some hold that the Veil itself is alive; a mysterious entity that did not like being pierced. Its violent reactions caused the Veilstorms, which tore across the earth and changed everything.
Through the tear came the Emissaries, the Dragons, and the Becoming.
What little was left of humanity was reforged from the fires of magic and winds of the Veilstorms. Sometimes, the changes made us stronger; usually, the unchecked magic made us into monsters.
The Birth and Death of an Age.
The Emissaries gifted us with immortality to repopulate the world, and left us with dark secrets. They forged three swords of power to choose our leaders. Three brothers appeared, and took the three swords. With the power of these artifacts, they were reshaped, forever changed into what they were most like inside: Arthur, Sigurd, and Nuada. Each forged a Realm out of the tiny area of habitable land left in the world. In the center, they founded Camelot, the glorious place of peace known as the One True City.
However, Camelot fell. The land broke apart and failed, and the three Realms were torn asunder by explosive magic. Three islands of civilization remained, lost in the vastness of the Stormlands.