Frank Castle made his debut as The Punisher in The Amazing Spider-Man #129 in 1974 as a villain. Castle was out to kill Spider-man, who was wanted for the murder of Norman Osborn, and will stop at nothing to get him.
But does that make him a villain for the rest of his comic career?
The Punisher is a “hero” who walks a very thin line between criminal and hero, and he knows it. Throughout his run The Punisher has had a very distinct inner monologue, analyzing everything he does giving the reader a direct line to himself. Yet he murders people, he finds the evidence, judges them guilty, then kills them with extreme prejudice. It isn’t very heroic to put a shotgun to the heads of every criminal he comes across.
A former U.S. Marine out for vengeance after his family is murdered while out on picnic Castle has developed a twisted sense of justice and isn’t merely driven by revenge anymore. He’s driven to kill the criminals, the super villains, the bad guys, he needs to kill them. In Civil War #6 as the battle is reaching new heights, The Punisher has just saved Spider-man and the Secret Avengers are planning their next move, two super criminals the “Plunderer” and “Goldbug” come forward. They pledge their own concern and say they support Captain America and the Secret Avengers, The Punisher immediately whips out two machine guns and blows them away.
No thought. No concern. Just immediate reflex and response to kill the “thieves and killers.” Captain America beats The Punisher senseless and all Castle can say is “They were bad guys Cap, thieves and killers…” before letting himself get pummeled.
Frank Castle might be an anti-hero, he might kill criminals at first glance, but he is ultimately a force for good. Albeit he has his own style but he’s a good-guy none the less.
We see him confronting the problem of vigilante justice, just like many other heroes do. But just like many other heroes, Frank Castle pushes on sacrificing what little is left of his sanity in order to protect the innocent. His selflessness in the face of knives, bullets, bombs, pain, injury, and anguish are what make The Punisher a force to be reckoned with. A force ultimately for good.