The Saturnian Criminal
Nemesis: Martian Manhunter
Other Major Foes: Zook
Appearances: One comic story.
Powers: Super-strength/speed/senses/durability, x-ray vision, spinning, energy projection and chameleonic shapeshifting. Vulnerable to oil.
Bio: The Saturnian Criminal sought refuge on Earth while pursued by lawmen from his world. He battered and stole the identity of Detective John Jones, which he used to set a trap for his pursuers. Jones was rescued by his pet Zook, and as J'onn J'onzz, used the Saturnian vulnerability to oil against the criminal.
Win: The Mercurian (?-1); Ryx (13-1); Scorch (5-4)
Lose: B'enn B'urnzz (?); S'vor (6-7)
Other Major Foes: JLA, Birds of Prey, Arsenal
Appearances: 50+ comics, playable character in Justice League Heroes with cameos in two other games.
Powers: Genius with an arsenal of specialized weaponry and cybernetic implants.
Bio: Prometheus' parents were outlaws gunned down by police when he was a child. A sort of reverse-Batman, Prometheus swore revenge against authority figures, eventually targeting the JLA while under the borrowed identity of Retro. Prometheus fared well against heavy hitters by using devices designed specifically to target their known weaknesses, but was less adept when faced with unfamiliar heroes. Prometheus continued to struggle with setbacks against lesser heroes, but rebuilt his reputation through the murder and mutilation of same before appearing to be executed by Green Arrow.
How's this for an unlikely Greco-Roman themed throwdown? On paper, the Saturnian is vastly more powerful than Prometheus, and they're both conniving identity thieves with murderous intent. Prometheus has taken on hordes of angry heroes at once though, and did a real number on Star City, even if its destruction wasn't his primary intent. However, Prometheus is just as easily felled by the deux ex machina he employs against good guys. If Prometheus goes for the commonly known Saturnian weakness to fire instead of the obscure issue with oil the Saturnian Criminal suffers from, he isn't likely to survive the encounter.