Robert Jordon's The Wheel of Time

In the beginning, the Creator made the Wheel of Time, which spins the Pattern of the Ages using the lives of men as its threads. The Wheel has seven spokes, each representing an age, and it is rotated by the True Source from which the One Power, a source of magic, is drawn. The One Power is divided into male and female halves, saidin and saidar, which work in opposition and in unison to drive the Wheel; those who can use this power are known as channelers.

The Creator imprisoned Shai'tan, known as the Dark One, a powerful, evil being, at the moment of creation, sealing him away from the Wheel. At some point, however, the Dark One was given purchase in the world through the machinations of well-meaning people and began his efforts to conquer the world, creation, even the Wheel itself. To counter this threat, the Wheel caused the Dragon, the champion of the Light and a channeler of immense power, to be born.

Due to the cyclical nature of the Wheel of Time, there can be no definitive victory for the forces of the Light; the war has been fought innumerable times since the dawn of Creation. The Dragon would defeat Shai'tan and seal him from the Wheel, only to have his work undone millennia later, necessitating his occasional rebirth to counter the continuing threat.

Robert Jordan's novels concern themselves with one incarnation of the Dragon in particular. About 3500 years have passed since the last war between Shai'tan and the Light, which the Dragon (known as Lews Therin Telamon in that life) ended by patching the hole in the Dark One's prison with the help of a group of other male channelers known as the Hundred Companions. Unfortunately, the Dark One managed to taint saidin, the male half of the One Power, with a counterstroke which brought madness and a wasting sickness to any man who channeled it. The taint quickly overcame Lews Therin and his companions and eventually drove every male channeler to insanity, with catastrophic results that changed the face of the world.

The rebirth of the Dragon, then, is viewed with hope and fear. On the one hand, the Dragon Reborn will be a channeler of saidin, vulnerable to the taint which Broke the World once before, and the prophecies promise that his rebirth will bring similar upheavals. On the other hand, he is the only one capable of defeating Shai'tan, who is once again reaching beyond his prison.