Source: comicvine.gamespot.com

7. Zack Overkill

(Incognito, Incognito: Bad Influences, Icon Comics)

Zack and Xander Overkill were dangerous and murderous mercenaries with enhanced strength and durability.

After their boss, The Black Death, was sent up the river to prison, they were caught in a trap, and Xander was killed. Zack was caught and turned state’s, becoming a valuable asset whose testimony put Black Death away for good. Zack was stuffed into witness protection and given drugs to suppress his powers.

But after ingesting a combination of governmental and recreational drugs, Zack figured out how to use his powers again to have fun. Bored and missing the violence, he also became a vigilante for funsies, stopping crime instead of committing it. When it was revealed that Zack and Xander were both clones and that a third, more vicious clone was on the loose, Zack teamed up with Xander’s ex-girlfriend Zoe Zeppelin to stop it.

In the end, Zack resolved to kill his old boss Black Death and joined up with the SOS. Aaaaaaaand then Incognito: Bad Influences happened, and all of that went to hell, but that was a different story.