Origin Story: Vietnam veteran Frank Castle puts his past as a killing machine Green Beret behind him, taking his wife and two kids on a delightful picnic in New York's Central Park. Their pleasant family times are interrupted by mafia gang war shenanigans (the worst kind), which spill out of the woods and onto their picnic blanket and cold chicken legs.
Frank's wife and kids are riddled with so many bullets that, even if they'd somehow managed to survive their 748,092 gunshot wounds, they'd most likely have died of lead poisoning. Frank's a little bitter about all of this.
Comic Book Consequences: Frank realizes that superheroes might be helpful in some cases (fighting super villains, rescuing kittens, ensuring $100 million four-day domestic box office grosses), but in two other areas are woefully inefficient: keeping mafia-related gun battles out of our nation's public parks, and mending a broken heart. Unable to repair the second problem but positively brimming with ideas about how to fix the first, Frank draws a white skull on some body armor, gets himself a fuck-ton of guns and paints the town scarlet with mobster blood.
What Would Have Happened in Real Life: Frank engages in a costly lawsuit with the city of New York, hoping to net $15 million for their negligence in failing to prevent mobster gunplay in public recreation areas. The city eventually wins the case on a technicality, since Frank had been picnicking in a non-sanctioned picnic area, and the bullet-ridden remains of his family technically counted as litter.
A Second Possibility: Furious that his family's murder has gone unpunished, Frank paints a white skull on some body armor, walks out onto the street holding guns, and shoots the first criminals he sees. He is promptly apprehended and incarcerated for murder, as his attention-grabbing costuming choice made him fairly easy to spot during his post-shooting spree getaway.
Frank Castle serves five consecutive life sentences without possibility for parole. He is briefly considered a vigilante hero during the Reagan era, when New York crime becomes a hot-button issue, but after Giuliani's term he fades into obscurity. He is currently interested in female pen pals looking for friendship ("...and then who knows?").