In the beginning...

The Creator created the Wheel of Time, which is time itself. The Creator imprisoned the Dark One outside of the Pattern at the moment of creation. A bore was made into the Dark One's prison, but it was sealed before he entered the world. It is now held closed by seven seals.

Pretty vague, eh? Jordan seems to want to keep the origin of the universe very vague.

According to Ishamael's philosophy (Guide), in each age the Creator and the Dark One have champions who lead their battle for supremacy. These champions are the same two souls who are reborn at the end of each age. The Creator's champion in the Age of Legends was Lews Therin Telamon, the Dragon. In the current age, the champion is the Dragon Reborn, Rand al'Thor. The Dark One's champion in the Age of Legends(info) was Ishamael who was partly trapped with him when the bore was sealed. By all appearances, Ishamael was still the Dark One's champion until his death at the end of The Dragon Reborn. Since that time, the Dark One has tempted several of his minions with the title Nae'blis, but that honor has apparently been bestowed on one of the new Forsaken, Moridin.

At the end of the current age the Creator's champion, the Dragon Reborn, will face the Dark One at the Last Battle, Tarmon Gai'don.

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