Warworld is an artificial world that was ruled by Mongul. Originally, Warworld was a place of civilized competition; a place where warriors and athletes from over the galaxy could compete for the honour of becoming Galactic Champion, bringing glory to their home planet. This change when Mongul fought and defeated the current Champion Grae'Dol, and took over Warworld by force and hosting it to deadly gladitorial games that is broadcast throughout the galaxy. Many alien beings were enslaved to Warworld and coerced to play the games as Mongul threatened to destroying their home planets. The only rule to the games is to simply to survive; in which any surviving gladiators who lose are killed by being exposed to the vacuum of space.
Mongul brought Warworld to Earth and enslaved Superman, Lobo, Cyclops, and Black Bolt in Warworld's roster in the 551st Warworld Games. Conventional military retaliation from Earth are proven useless to attack Warworld due to its energy shields, in which Mongul had publicly and overtly threatened to destroy Earth. Mongul's reign over Warworld was ultimately overthrown by the Justice League and the X-Men, and Grae'Dol regain control over Warworld and returning it back to its original glory.