MONGUL!

In the deep reaches of space is an artificial planet which roams the galaxy, raiding planets for their resources and, particularly, their most valiant warriors. These are kidnapped and trained to fight in massive gladiatorial combats for the amusement of millions. This is Warworld, and its ruler for uncounted years was the terrible Mongul.

When Superman exiled himself into space following his encounter with General Zod, he was captured by emissaries from Warworld and forced to fight in Mongul's games. Superman, however, refused to kill, an action which drew Mongul's ire. Mongul faced Superman in open combat and lost.

Superman's defeat of Mongul caused chaos on Warworld, and the planet's ruler was overthrown and replaced. Disgraced, Mongul vowed revenge against Superman. His opportunity came when the Cyborg crossed his path.

The Cyborg, too, had vowed to seek vengeance on Superman. Together, the two of them devised a plan. The Cyborg returned to Earth shortly after Superman's death at the hands of Doomsday, and claimed to be the fallen Man of Steel returned to life. Using this cover, the Cyborg destroyed Coast City, preparing the area for Mongul's arrival.

The pair's fiendish plan would have led to the subjugation of the Earth, had not the real Superman returned from the dead and, together with Supergirl, Green Lantern, and Superboy and the Man of Steel (two other "replacement" Supermen), defeated Mongul and the Cyborg.

Years later, Superman was quite displeased when Mongul crashed on the planet Earth--a displeasure not lessened by the revelation that this was in fact the son of the ruler of Warworld. But Mongul had not come to Earth on his own--he had, he told the Man of Steel, been thrown to the planet by the cosmic entity known as Imperiex. Imperiex was coming to destroy the universe, and Mongul wanted Superman's help to defeat him.

But before Superman could hope to go up against the power of Imperiex, Mongul needed to train the Man of Steel, to help Superman better utilize his amazing powers. In deep space, in the depths of the ocean, and on desert plains Mongul taught Superman to tap into the deepest reserves of his power and combine his abilities to increase his effectiveness as a fighter. After weeks of training, the two went into deep space to confront Imperiex.

Superman and Mongul's battle with Imperiex was fierce, but the two eventually triumphed, forcing Imperiex to retreat. At that point, Mongul attacked Superman, seeking vengeance for Superman's defeat of his father. But Superman had been prepared for this treachery, and managed to subdue Mongul just as the intergalactic bounty hunter Lobo arrived on the scene.

Mongul escaped from Lobo and returned to Metropolis, this time accompanied by his sister, Mongal. The two sought out Superman, supposedly coming with a warning that Imperiex was not truly defeated. However, when they attacked and endangered innocent lives, Superman was less inclined to listen to them. With the aid of his dog Krypto, he defeated Mongul and his sister.

Mongul was taken into custody by STAR Labs, where he was then turned over to Federal authorities for inclusion in President Luthor's Project: Suicide Squad, a group of super-villains drafted into service in exchange for leniency in sentencing. The mission of Project: Suicide Squad was to travel to the moon to release Doomsday from its JLA transporter prison, so that the monster could be used in the upcoming war against Imperiex.

Mongul, along with several other villains, was killed by Doomsday in the course of this mission. His sister became the ruler of Almerac following Maxima's death during the Imperiex War.