Gog is the name of several different fictional character in the comics published by DC Comics. The first version first appeared in New Year's Evil: Gog #1, (February 1998), and was created by Mark Waid and Jerry Ordway.
The first version of Gog was known as William, the sole survivor of a nuclear disaster in Kansas that was caused by the Parasite's shattering of Captain Atom during a battle with the Justice League, and became a believer in Superman as a savior, even creating a church dedicated to his philosophy as he tried to find meaning in the cataclysm that had taken place. One day, Superman visited him and told him that he wasn’t the omnipotent, perfect being that William thought he was, shattering William's world view and mentally unbalancing him. When the Quintessence (Shazam, Ganthet, Zeus, Highfather, and the Phantom Stranger) invested him with a portion of their vast power, William, now known as Gog, went insane and blamed Superman for his misfortune, believing him to be the Anti-Christ who had allowed the Kansas disaster to take place to regain his standing in the world.
Using his new found powers, Gog killed Superman. Unsatisfied by his victory, Gog traveled 24 hours back in time, found Superman, and killed him again, repeating the process over and over, going backwards one day further each time, and each time varying the means of Superman's death and absorbing portions of the slain Supermen's power. When he arrived on the day that Superman and Wonder Woman's child was born, the entire Justice League tried to stop him, but they failed, and Gog took the child, deciding to go directly to the past where he intended to trigger the Kansas cataclysm almost twenty years early, burning Superman's insignia into the countryside.
Gog's actions exposed the existence of Hypertime, a fictional construct similar to the Multiverse in pre-Crisis stories. Gog unknowingly passed into an alternate timeline each day he traveled back in time, effectively killing a different Superman at every turn. As a result, the Phantom Stranger was forced to recruit time traveler Rip Hunter of the Linear Men, the only other person aware of Hypertime, in an attempt to preserve the secret, the other members of the Quintessence refusing to act to stop Gog for their own personal reasons.
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