Wolverine

He’s the best there is at what he does, and what he does isn’t very nice, but would he be the best Green Lantern? Well, perhaps not, but Wolverine definitely has it in him to be a damn good one.

Although his rapid regenerative healing factor undoubtedly helps, the fact is that Wolverine has kept on fighting when the odds were stacked against him time and time again.

He has continued to fight after having his heart ripped out, he has literally willed himself back from the dead, he has resisted the mental attacks of the likes of the Phoenix and he has continued to fight when he was forced to experience every ounce of pain, every bullet wound, every broken bone, every nightmare and every bad memory he has ever experienced all at once.

While he might not have the creativity to produce particularly imaginative constructs, he undoubtedly has the willpower to wield a Green Lantern power ring with great competence and efficiency.