Atmos

Atmos is the main setting of the Cartoon Networks' animated series, Storm Hawks. A massive landmass, in which it's skies are divided into several zones (dubbed as "Terras"), while it is also distincted from "the Wastelands", a region located underneath the landscape. It's capital city is Terra Atmosia,  the base of the influential Sky Knight Council, the highest order of the land. It is occasionally threatened by the Cyclonians, led by Master Cyclonis, who hailed from Terra Cyclonia, the darkest territory of Atmos, though it has been defended by the Sky Knights, including Aerrow, saving the land from the evil forces.

Regarding the villain tournaments, Atmos is displayed by Terra Cyclonia, where it appears as one of the efficient locations of the series. Other than that, Atmos is not heavily featured in the villain tournaments context.