King Jaxx was the supreme sovereign of the Red Saturnians of Saturn-One, and found that the underclass White Saturnians had formed a coup against his regime necessitating his wife Jarlia hiding their son Prince Jemm. This lad had snuck away from his home world and headed for Earth-One to live in exile in the city of Harlem. However, the White Saturnian known as Synn had tracked the lad down and sought the energy crystal embedded in his head as an energy resource. This jewel gave Jemm energy powers in addition to his superstength and flight.
Then there was Prince Porra of a Saturn-Two whose misguided father King Ool and his brother Prince Gorla sought to rule Earth-Two, which brought them into conflict with Zatara. The top-hat troubleshooter recruited Porra and finally convinced Ool and Gorla the folly of trying to conquer the human home world. Remarkably, Porra's people look like the green Martians of Mars-One and Mars-Two, and in fact on the former world those inhabitants had created the race of red skinned clones to help them colonize Saturn. Apparently, their counterparts simply migrated a portion of their population to Saturn-Two.
While Jemm had a few adventures while on Earth-One before returning to his world, Porra never bothered to appear on Earth-Two as Zatara's awesome array of powers overwhelmed he and his kin. Also, they didn't have superpowers as had their doppelgängers on Saturn-One, instead relying on all sorts of strange unearthly equipment in their egotistical endeavors. Jemm encountered Zatara's fellow Action Ace Superman who was as kind yet firm as his colleague towards the Saturnians.