Jim Shooter, the iconic comic book writer who broke into the business when he was just 14 years old, has died after a long battle with esophogeal cancer. He was 73.

The name might not mean anything to you unless you’re one of us—the ones who grew up reading comics not just for the capes and powers but for the strange alchemy of myth and medium. But if you’re one of us, you already know. Jim Shooter changed everything.

He sold his first comic book script to DC when he was just 14 years old. Fourteen. And not just a plot, either—Shooter sent in a full script, penciled layouts and all, for a two-part Legion of Super-Heroes story. Mort Weisinger, the famously prickly editor at DC, bought it. Not only that, he had pro artists like Sheldon Moldoff and Curt Swan use young Shooter’s rough layouts as the actual storytelling foundation for the finished pages. Who does that? What kind of kid just reverse-engineers the entire comic book industry on instinct, executes it like a pro, and gets published?

The kind of kid who ends up becoming one of the most influential editors in the history of Marvel Comics, that’s who.

Shooter understood story. Even as a teenager, he could see that the Marvel books of the mid-60s had an edge DC lacked—more heart, more action, more narrative momentum. So he didn’t just pitch any comic. He found the one he thought needed the most help and targeted Adventure Comics, home of the Legion. Then he introduced four new Legionnaires in one story: Karate Kid, Princess Projectra, Ferro Lad, and Nemesis Kid. Four. In a single pitch. One of them turned out to be a traitor, which made it all even juicier.

And yes, Karate Kid fights Superboy. For pages. It’s a thing of beauty.

By his late teens, Shooter was writing regularly for DC, even introducing villains like the Parasite to the Superman mythos. But once he graduated high school and tried to make a go of it full-time in New York, the money didn’t hold up. He stepped away, worked in advertising for a few years. It took a fanzine—and some very dedicated Legion fans—to coax him back. He was 23, and already on his second career in comics.

Eventually, DC politics wore him down, and Shooter jumped to Marvel. There, he worked as both a writer and an editor. His work on Avengers during this period is legendary—especially the dark, character-driven arcs involving Hank Pym’s mental health. He had a knack for writing deeply flawed characters without making them feel like caricatures. He understood that action mattered, but consequences mattered more.

In 1978, Marvel handed him the keys to the kingdom: Editor-in-Chief. At just 27 years old.

Marvel had churned through EICs like Spinal Tap drummers in the years after Stan Lee stepped aside. Shooter brought order. He insisted on deadlines. He separated editorial and writing duties. He pissed off more than a few big names, and some left for DC. But under Shooter’s watch, the Direct Market came into its own, Marvel sales soared, and legendary creative runs exploded across the line: Claremont and Byrne on X-Men, Byrne’s Fantastic Four, Simonson’s Thor, Miller’s Daredevil, Stern’s Avengers, and more.

He also wrote the first major crossover event: Secret Wars. Love it or hate it, that thing sold.

Shooter also launched The New Universe, Marvel’s attempt to do superheroes “realistically.” It didn’t quite land, but you have to respect the swing. Shooter was never afraid to try something big.

In 1987, he was fired. Too many clashes with too many creators. Vision and ego make a volatile mix, and Shooter had both in abundance. But he didn’t vanish. Not even close.

He tried to buy Marvel. When that failed, he founded Valiant Comics—using Solar, Magnus, and Turok as anchors for an entirely new shared universe. And for a while, it worked. Valiant was a juggernaut, the rare indie publisher to rival Marvel and DC in sales and critical acclaim. Then the boardroom drama kicked in again, and he was out.

So he started Defiant Comics. Then Broadway Comics. He returned to Legion (twice). Revived Solar and Magnus again for Dark Horse. He just kept going. The guy was tireless.

You don’t have to agree with everything Jim Shooter did, or how he did it. A lot of people didn’t. But nobody, nobody, worked harder to make comics better. He thought deeply about what the medium could be. He fought to elevate it. And he was often right, even when it made him unpopular.

He wasn’t perfect. He was ambitious, stubborn, and unrelentingly principled. But you know what? That’s the kind of person who changes things.

And Jim Shooter changed everything.