The Punisher (Marvel)

Punisher is a violent vigilante from Marvel comics and varies from being a dark antihero along the lines Judge Dredd or Spawn to being an outright protagonist villain depending on the writer or story.

Driven by rage at the death of his family the Punisher hunts down criminals and puts them to "justice" - often killing them in brutal ways, though he is also known to settle for intimidation or torture.

Punisher is one of Marvel's more sociopathic antiheroes and for this reason can easily be seen as a villain by some, however in the end Punisher does fight on the side of good: albeit he often utilizes tactics that would be undreamt of by more conventional (and ethical) superheroes.