Hal Jordan, once called the greatest of the Green Lantern Corps, fell victim to the corrupting fear-entity known as Parallax. Under its influence, he destroyed the Green Lantern Corps, and tried to remake the universe - and failed. He redeemed himself, somewhat, in death by saving the Earth from a Sun-Eater.
In the afterlife, he would be called upon once again, to act as the host of the cosmic entity known as the Spectre. Through the Spectre's power, and with the assistance of the Guardians of the Universe, Hal Jordan would come to live again - and serve once more as a member of the Green Lantern Corps.