With every turn of the century, the Gods and Goddesses of different parallel worlds come together to participate in a show of strength by bringing along a representative from a species they rule over to compete in a battle royale-style tournament where the last person standing wins. These representatives were known as "Champions".

Leo Mathers was chosen last-minute to be the representative of the human race and as 'Champion' must fight to the death alongside other species from other worlds. From Elves, to Beastman, to Demons, to Centaurs, and other mythical and extraterrestrial beings that had far surpassed humanity in both strength and skill.

Overlooked and scorned by the other species, Leo must use all the cunning and wit he could muster to survive the many phases in the tournament and to be ultimately crowned victor above all and to prove to all the other species that humanity is not to be underestimated.