@Killemall: He used to play Chess against the League and cheat thanks to his telepathy. He was physically frail until he entered the Flames. His body was destroyed, but he reformed it. He then took on the JLI with his new powers. He turned Gotham City into Hell, and had the League dead to rights, except Batman had a plan and Vibe saved the day.
As far as him taking on multiple heavy hitters and winning, Virtue and Vice was legit, but it was Despero's highest showing.
He would show up in Superman/Batman and he got oneshotted by Superman's heatvision. And then there's him versus Aquaman's sharks.
I still think he wins though. He took on Lobo and the JLI in "Breakdowns."