8. Ant-Man (Eric O’Grady)
S.H.I.E.L.D. agent Eric OGrady stole the Ant-Man armour from his friend’s dead body and went on to use the suit of Marvel’s premiere diminutive superhero for his own gain, repeatedly. He was one of the least likeable superheroes ever (and actually a practising villain for a time), and even used his shrinking powers to stalk women.
From time to time he did help save the world, though, and Eric did eventually get a chance to make amends for his crimes when Steve Rogers overlooked his years of criminality and invited him to join the Secret Avengers. It was as a member of this team that Eric eventually met his end. He was beaten to death by a group of androids that worked for a supervillain team called The Descendants. He had one final moment of redemption at the last; as he fought off the robots long enough for a young child to escape.
Although the Avengers thought Eric had survived for a time (The Descendants sent back a robotic decoy in his place), Eric’s death was never in question for the audience. The fact that he died at the end of his redemptive arc is rather fitting for the character, too, so it’s probably for the best that he hasn’t been revived.