Marvel Comics editor in chief Axel Alonso at the publisher’s New York City headquarters.
Chris Buck for TIME
August 27, 2015 6:37 AM EDT

In the Garish pages of the comic books, Thor stands out as one of the most macho of all the superheroes, an already testosterone-soaked group. Created by the legendary Marvel Comics team of Stan Lee and Jack Kirby in 1962, Thor is a god of Asgard, dispatched to Earth to live among humans. Armed with an enchanted hammer and drawn with bulging muscles and flowing blond tresses that wouldn’t be out of place on a romance-novel cover, Thor has always been both magical and manly.

Except that now he’s a she. In one of the more controversial superhero makeovers ever, Thor’s hammer was passed last fall to a human woman. The hammer duly granted her godlike powers, and in the inscrutable logic of the comic-book universes, she now is Thor. When first confronted with a group of condescending villains, she pauses to rally, telling herself, “Quick, say something badass.” Then she promptly polishes off the fiends. “The name isn’t ‘wench,'” she growls at them. “I am the goddess of thunder.”

The arrival of a female Thor–and a series of other diversity moves that include a half-black, half–Puerto Rican Spider-Man and the installation of a woman in the role of the crusader known as Captain Marvel–is the work of a team at Marvel Comics led by a former journalist named Axel Alonso. Since taking over as Marvel’s editor in chief in 2011, Alonso has recruited new writers, killed moribund series and blown up the narratives of beloved characters.

The changes have been controversial among some comics fans, a notoriously obsessive group. Protests on social media have been loud and bitter. But Alonso’s new heroes–particularly those of the female persuasion–are turning out to be good business. At a time when films from Marvel’s movie division have come under fire from some critics for their predominantly male casts, Alonso and his comic-book writers are proving there’s a paying audience for diversity. (Both Marvel Comics and Marvel Studios are units of entertainment giant Disney.) Sales of Marvel titles at comic-book stores reached $186 million last year, up 8% from the previous year, according to data from Diamond Comic Distributors, as fans snapped up the new Thor and other titles.

If the metamorphosis keeps up, it will mark a new turning point for a medium with a powerful hold on the American consciousness. Comic-book heroes have been part of the national mythology going back to World War II, when Superman stood for “truth, justice and the American way,” and more recently have tackled everything from civil rights to terrorism. If they have mostly flubbed the subject of gender equality, they are at last making a heroic effort to catch up.

Alonso is 48 years old and has a wife and son, but he sports a shaved head and an arm tattoo of the Mayan calendar that projects a fitting countercultural vibe for the comic-book world. He says he learned early just how meaningful the implausible characters in comics can be. When he was growing up in San Francisco, the son of a Mexican father and a British mother, comic books were part of a weekly family ritual. “My abuelita, my grandma, used to pick me up on Fridays after school, because my mom worked late, and take me to the dime store, and I would buy a comic book,” he recalls. “The first comic book I bought was called New Gods. It was really violent and crazy, and I loved it.”

He says he gave up comic books as a preteen because he “didn’t want to be uncool” and fell in love with sports. After high school he attended the University of California, Santa Cruz. Then, after earning a master’s from Columbia Journalism School, he worked as a freelancer. Writing assignments ranged from a feature on the world’s best handball players to a profile of a pimp who moonlighted as an inventor. Tiring of the infrequent paychecks, he spotted an ad for an editor job at DC Comics–home to Batman, Superman and Wonder Woman–and decided to apply. “I got an interview because I’d written a [newspaper] story in which a guy who had stolen the girlfriend of one of the editors at DC came off looking like a jackass. So this editor offered me the job on the spot,” he says. “It was meant to be.”

After six years, competitor Marvel recruited him away from DC in 2000. He began changing both the faces and the stories of Marvel’s comics. He edited Truth, featuring the first black Captain America, as well as a controversial western comic called Rawhide Kid, about a gay cowboy who had a gun dangling suggestively between his legs. He lobbied his fellow editors–at first unsuccessfully–for a Black Widow comic after the character played by Scarlett Johansson made her big-screen debut in 2010’s Iron Man 2.

By 2011, Alonso had established himself as one of the comics world’s most successful editors as well as a fixture at fan events that are critical to promoting new titles, and Marvel promoted him to editor in chief. One of his first moves was to cancel a struggling series called X-23 that chronicled a female genetic clone of fan favorite Wolverine–which, at the time, happened to be Marvel’s only comic with a solo female lead. Even though the decision was a financial no-brainer, Alonso found it difficult. He knew mothers and fathers on his staff wanted empowered female characters who would appeal to their daughters–and remembering the lack of diversity in the comics of his youth, he empathized.

“It was always in the back of my mind that I’d like to see superheroes look like me or look like my son. So I’m always striving to make the next great Mexican superhero,” says Alonso. “When we decided to cancel X-23, it just hit us that this was really bad.”

So he resolved that Marvel would somehow develop a female superhero who would also be a hit in the marketplace. “I didn’t hand down any sort of mandate–Make Thor a woman–but I just kind of told the editors, ‘Keep this in mind. Write something we can sell.'”

Alonso’s imperative collided with the restlessness of writer Jason Aaron, who wanted to find a surprising new direction for Thor, one of Marvel’s staple superheroes. In comic-book lore, Thor’s magical hammer, called Mjolnir, can be lifted only by whoever is deemed worthy to carry it. Aaron decided that the male Thor no longer qualified. “I liked the idea of Thor as a god who was always questioning his own worthiness,” Aaron says. “I like to think of him waking up every day and looking at the hammer and not knowing if he was going to be able to pick it up.”

But tampering with Thor–whose portrayal by actor Chris Hemsworth has helped fuel Marvel Studios’ cinematic success–was risky. Aaron took his idea to one of Marvel Comics’ semiannual retreats where dozens of writers and editors gather to chart the year ahead. His pitch was simple. Thor’s hammer had been handed briefly in the past to an extraterrestrial and even an amphibian. So shouldn’t fans be able to get behind another unfamiliar species–woman–lifting the weapon?

“I think if we can accept Thor as a frog and a horse-faced alien, we should be able to accept a woman being able to pick up that hammer and wield it for a while, which surprisingly we’ve never really seen before,” he says. Alonso approved, and work began on what would become Thor: The Goddess of Thunder #1.

The push for diverse characters expanded well beyond Thor. In the past two years, Alonso and his team have launched 16 new titles starring women. One of the most significant moves was transferring the mantle of Captain Marvel, a hero who first appeared in 1967 to the Carol Danvers character, who had been toiling in the understudy role of Ms. Marvel.

That created a job opening in the superhero universe–and two of the top creative women in the comics industry proposed a fresh character to fill it. Marvel director of content and character development Sana Amanat–whom Alonso calls the driving force behind the publisher’s female-friendly initiatives–reached out to G. Willow Wilson, a highly regarded writer who also happens to be one of the few Muslim women in the business. In February 2014, they introduced a new Ms. Marvel: Kamala Khan, a 16-year-old Muslim girl struggling to fit in who uses her shape-shifting powers to protect her hometown of Jersey City, N.J. Some fans blasted the new story line–a few even accused Amanat and Wilson of somehow promoting jihad–but the book quickly earned a spot on the New York Times list of best-selling paperback graphic books.

Wilson says the payoff was worth the risk. “I thought they were going to need an intern to open all the hate mail,” she says. “Now I have people you would least expect–like this giant, blond, bearded guy I met in Denver–telling me how they connect to Ms. Marvel because they were made fun of in school for being different.”

Devising the next generation of superheroes to reflect the diversity of potential comic-book readers is one thing. Disrupting the fictional universes for longtime fans who can cite dialogue just from the mention of an issue number is another. The first issue of the new Thor reached stores on Oct. 1, 2014, but Aaron decided to keep the actual identity of the new goddess a mystery for several issues to build interest. (Spoiler alert: she is Dr. Jane Foster, Thor’s longtime comics companion.) Three months earlier, Alonso arranged for the reveal to take place before the all-women hosts of television’s The View–and the backlash from some fans was swift and brutal. “This is PC gimmick bull,” one angry fan tweeted.

Aaron nodded to the controversy in the pages of Thor, having a villain complain, “Feminists are ruining everything.” (Thor promptly breaks his jaw.) Other fans, meanwhile, moved quickly to back the new heroine. “I call the kind of guys who say Thor can only be this one dude ‘fake nerds’ because they don’t know their comic-book history,” says Brittany Baker, a 25-year-old who says that when she was growing up in Toronto, she would pretend she was buying comic books for her brother in order to fend off male customers who would question her fan credentials.

More to the point for Marvel, these new titles are selling well and showing how a diverse cast of characters can attract new readers. Though the industry’s conventional wisdom long held that female leads were doomed to fail, Thor: The Goddess of Thunder has outsold the male-Thor comic by 30%. Ms. Marvel was the company’s top digital seller in 2014. And the debut issues of four of Marvel’s female titles–Thor, Spider-Gwen, Princess Leia and Ms. Marvel–each individually sold over 200,000 copies, or more than double the typical number for so-called event titles.

In 2014, women made up an estimated 37% of Marvel Comics’ fan base, up from 25% only a year before, according to Facebook data gathered by analyst Brett Schenker. This year’s Publishers Weekly survey of comic-book retailers concluded that women ages 17 to 30–the same women who have made young-adult franchises like The Hunger Games and Twilight successful–are the fastest-growing demographic in comics. “Young women have been really responding to the comics where the female characters are designed to appeal to girls, not boys,” says Juliette Capra, events director at Fantastic Comics in Berkeley, Calif.

Store owners also say the characters who are selling best are the ones most fully formed. One example is Captain Marvel, whose author, Kelly Sue DeConnick, has crusaded publicly against comics that objectify women and has attracted a legion of fans who call themselves the Carol Corps, after character Carol Danvers. “If you can take out your female character and replace her with a sexy lamp and your plot still functions, you’re doing it wrong,” she says. “I just want our female characters to have their own motivations and complexities.”

Part of Carol Danvers’ transformation into a modern hero came with an outfit redesign that ditched a spandex leotard for a pilot’s uniform. Capra says girls who come into her store gravitate toward other titles that have altered characters’ styles from sexy to practical. When DC put Batgirl, a Ph.D. candidate, into yellow Doc Martens instead of heels, the shoes sold out at major online retailers within hours. DC is, in fact, increasingly mirroring the strategy of its big rival Marvel. In addition to giving Batgirl a less stereotypical look, the publisher earlier this year announced a partnership with Mattel to produce a TV show and toys based on DC’s female characters.

Comic books are just a small fraction of the big money in the massive superhero industry. Last year, for instance, Disney recorded a 22% surge in net income, largely thanks to Marvel’s Guardians of the Galaxy film. Disney doesn’t break out financial results for Marvel specifically, but its fiscal-2014 overall revenue was $48.8 billion, mostly from TV, movies and theme parks. In contrast, the entire consumer-products segment–which rolls up comic books along with things like toys and other character-emblazoned goods–was about 8% of total revenue.

On movie screens, at least for now, there has been little change. When Marvel’s Avengers returned this summer–racking up an estimated $1.4 billion at the international box office so far–it was Hemsworth’s he-man version of Thor who fought alongside Iron Man and Captain America. Only one of the 10 film projects Marvel has announced for the next four years, Captain Marvel, stars a woman, and it won’t hit screens until 2018. DC’s much discussed Wonder Woman movie will premiere a year earlier.

Alonso acknowledges the criticism over Marvel Studios’ heavily male tilt, but he’s more focused on the possibilities in the pages of the comic books his writers and artists are creating–and believes Marvel Comics will help bring about change in its role as an incubator for new movies. “We are responsible for building and occasionally breaking things,” he says. “If something works, that’s an indication for how movie audiences might respond.”

His next chance to build and break will come this fall, with a complete revamping of Marvel’s titles, all of which will connect with one another in what’s known in comic circles as a universe. The reboot will let writers explore new characters from fresh angles and may even serve as fodder for future films. The company has dubbed this the “All-New, All-Different” Marvel universe, and it will include a chance for the female Thor and Ms. Marvel to join the Avengers team for the first time.

Fans appear ready for more. At this summer’s Comic-Con in San Diego–an annual event that was once dominated by fanboys but now has close to a 50-50 split of male and female attendees–a 9-year-old girl wearing Ms. Marvel’s signature lightning bolt stole the show at a panel when she stood on her tiptoes to ask questions. Out in the hallways, women roamed up and down in the costumes of their favorite characters. One of them, Bennett Cousins, came dressed as Thor and was swarmed by photographers and bloggers. “What does it take to be Thor?” one asked. Hoisting a foam hammer, she replied, “Ovaries.”

This appears in the September 07, 2015 issue of TIME.

Write to Eliana Dockterman at eliana.dockterman@time.com.

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