The original "World War III" saga was a narrative arc of the JLA series written by Grant Morrison and drawn by Howard Porter in 2000 (over JLA #36-40), and currently in print as the JLA, Vol. 6: World War III paperback. This was the final arc written by Grant Morrison and provided explanation for hints dropped over his tenure about the importance of the JLA as "forerunners" in defending the Earth from an impending menace.
Lex Luthor, failing to defeat the JLA, formed a new Injustice Gang consisting not of villains who mimic the JLA, but with villains that posed major threats to them in the past. The villains were (in order of recruitment) Prometheus, Queen Bee (Zazzala), and General Wade Eiling. With a deadly plan in mind, this new team was able to infiltrate the Watchtower via the Ghost Zone and defeat the JLA. As the JLA was about to fight back, they soon found out that the Injustice Gang were not doing these things under their own will, but were being controlled by an unknown force. The latter is revealed to be the cosmic entity Mageddon, an extremely ancient living weapon originally intended to be used for wars among primal cosmic gods. Mageddon had been influencing the thoughts of the population of Earth to promote a world-wide state of war, and ultimately aimed to destroy the planet.
The JLA rallies the help of many heroes of the DC universe, most notably that of Aztek (a Grant Morrison creation), who is blinded and sacrifices himself in the effort; it is revealed that Mageddon, under the name of "Tezcatlipoca", was indeed the menace Aztek was originally created to oppose. Finally, the JLA is able to confer superpowers to the population of the Earth, who unite in the decisive effort to vanquish Mageddon and save the planet, keeping it occupied long enough for Superman- trapped at the "heart" of Mageddon- to absorb the anti-sunlight powering Mageddon's systems and disable it for good.
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