Grae'Dol participated in Warworld's once civilized competition to becoming Galactic Champion. At the very last stage of competition, he was overpowerd and lost to Mongul. Soon after Mongul claimed his title, he immediately seized Warworld and enslaved Grae'Dol in his deadly gladitorial games. Grae'Dol survived through the games and, despite his dire circumstance, have hopes of becoming free from Mongul's tyranny.
In the 551st Warworld Games held over Earth, Grae'Dol was teamed with Im'Thror against Superman, Lobo, Cyclops, and Black Bolt in Murderball. During the game, Superman planned in deliberately tying the game and allowing the participants to live; Grae'Dol quickly catches on to Superman's plan and joined him in creating a tie-breaker.
Grae'Dol saw potential in Superman and his companions' determination in freeing themselves and stopping Mongul. A fact that Grae'Dol shared their determination; furthermore, Grae'Dol realized that Mongul feared Superman and is strongly convinced that the Man of Steel will overthrow the Gamesmaster. The Kryptonian's threat to Mongul, however, convinced the Gamemaster in arranging Grae'Dol to fight Superman in the Final Conflict while threatening to destroy Grae'Dol's home planet with his planet-killer weapon.
Grae'Dol fought Superman and urged him to finish him in order to buy time to defeating Mongul. However, Superman refused to kill him and defeat him with a minor fraction of his powers. Following Mongul's defeat, Mongul's fate was left to the vengeful gladiators until Grae'Dol quickly decided to spare Mongul's life as he reasoned that killing Mongul would be proving Mongul's belief that his gladiators are nothing but animals. Grae'Dol turned Mongul over to the Green Lantern Corps and stripped him of his title of Galactic Champion, in which he offered it to Superman. Superman humbly turn down the title as he points out that it was a team effort that defeated Mongul. Instead, Grae'Dol is entitled to Gamemaster of Warworld and hosting it back to its honourable competition.