The Human Flame
Nemesis: Martian Manhunter
Other Major Foes: The JLA, The Army of the Endangered
Appearances: 15+ comics.
Powers: Fire projecting technology. As Inhuman Flame: Flight, strength, nigh-invulnerability and size alteration.
Bio: Mike Miller was a minor inventor/thief who had a brush with the greatness of Libra. This led him to alienate pretty much the entire metahuman community, until he was transformed into the monstrous "Inhuman Flame" and trapped in outer space by Green Lantern John Stewart.
Lose: Human Squirrel (6-7); Scorch (4-9)
Nemesis: Green Lantern Kyle Rayner
Other Major Foes: Green Lantern Corps
Appearances: 40+ comics.
Powers: Fire generation and manipulation allowing flame blasts, energy constructs and flight.
Bio: Martyn Van Wyck was kidnapped by the Controllers and turned into a prototype for their own corps to rival the Green Lanterns. Following a mental breakdown, Effigy joined several villains in plotting the murder of J'Onn J'Onzz, the crime for which he was executed by the Spectre.
Lose: Fernus (2-10) and Scorch (?)
Both of these guys have fire powers and sorta-kinda killed the Martian Manhunter, except not really. They've also been minor annoyances to Green Lanterns. I'm not especially fond of either character, and given their swift first round exits in both years of March Madness contests for which they qualified, you're not big on 'em either. The "classic" Human Flame wouldn't stand a chance, but his final Inhuman Flame form could probably do Effigy in. Whoever wins, it'll be a first for either party.