CLEVELAND, Ohio -- Sales of major superhero comics have declined precipitously since their peak in the mid-1980s and early 1990s. While new issues from publishers like DC Comics and Marvel Comics in that era occasionally sold more than a million copies, today even the most famous comics are lucky if they eclipse 100,000 for a single issue.

A Marvel Comics executive recently made headlines when he appeared to blame the slide on an uptick in diverse characters. Marvel has introduced more female and minority superheroes in recent years. But local comic-book store managers and owners say the slump is more complicated than that.

Sales of titles starring household names like Spider-Man and Wonder Woman have fallen thanks in part to reader fatigue and a greater number of alternative titles not published by the major comic book companies, they say.

Even with the decline, local comic book store owners and managers say they've persevered thanks to greater diversity of titles and sales of graphic novels.

While some stores have shuttered over the years, Cleveland still has no shortage of comic-book shops.

Cleveland's comic book stores

Imaginary Worlds Comics on Cedar Road in Cleveland Heights opened its doors just two years ago. B & L Comics Cards and Nostalgia and North Coast Nostalgia in Parma -- both of which have existed for more than three decades -- are less than half a mile apart on Ridge Road. John and Carol's Comic Book Store -- named after the current owner and his mother, his former partner -- has been in operation for nearly two decades in a shopping plaza in Kamm's Corners. And Ground Zero Comics and Cards in Strongsville is noted for life-sized figurines of famous superheroes. There are many others.

"The only thing we really compete on are the new comics that come out every week," North Coast Nostalgia manager and longtime employee Adam Barsa said. "Other than that we all have our different secondary markets."

Those secondary markets include toys, clothing and -- perhaps most importantly -- old issues of classic comics.

Comic books are still a niche market, so the stores also serve as a place where like-minded fans can congregate and talk about their favorite characters.

"I compare (comic-book stores) to Cheers," said Allen Leaghty of Parma, referring the long-running sitcom involving a bar that survives on a group of regulars who love to chat with the bartenders. "They're always glad you came."

Leaghty was one of a half dozen people scouring through North Coast Nostalgia's collection on a recent Wednesday afternoon. New comics arrive on Wednesdays and there's usually a crowd.

Leaghty chatted with a store manager for several minutes about Nightwing, a lesser-known DC Comics superhero, and he seemed delighted to talk to a Cleveland.com reporter about Venom, an anti-hero who was once Spider-Man's most feared enemy.

"He's my favorite character of all time," he said.

Leaghty said he reads many of the classic titles, including ongoing comics that star Spider-Man and Batman. But the Parma man said he also enjoys horror comics based on popular franchises like "Alien vs. Predator" and "A Nightmare on Elm Street."

Book stores like Barnes and Noble sell popular comic-book titles, and readers can subscribe and have them delivered. But Leaghty said he relishes the opportunity to talk about his favorite titles with other fans.

Why major title sales have declined

Marvel Comics have intentionally added more female and minority superheroes to their lineup in recent years. Sam Wilson, who now holds the Captain America mantle, is black. And Kamala Khan, the latest character to go by the name "Ms. Marvel," is a Muslim woman.

But during a recent two-day meeting with retailers, Marvel Comics Vice President for Sales David Gabriel seemed to imply that such diversity was hurting the publisher's bottom line.

"What we heard was that people don't want diversity," he said.

He later backtracked, but his clarification didn't stop online news outlets from jumping on his initial comments. A day later the internet was filled with headlines like, "Marvel Comics Exec Claims Focus on 'Diversity' Behind Falling Sales."

But local industry insiders said the decline of Marvel and DC titles is more nuanced.

Individual comics have an average sticker price of around $4. Today, many popular titles hit shelves twice a month, making comics an expensive habit for fans interested in multiple titles.

Reader fatigue is another problem, store owners and managers said.

Marvel Comics struck gold with its "Civil War" crossover storyline in the mid-2000s. That story begins when a law is passed requiring everyone with superpowers to register with the U.S. government or face imprisonment. The story was wildly popular. Fans found the harrowing choices their favorite characters were confronted with compelling.

Marvel created six issues of a "Civil War" comic book and each superhero and superhero team had their own "Civil War" story.

"That's to get you to buy other titles" you wouldn't normally buy, said Larry Zjaba, owner of B & L Comics Cards and Nostalgia on Ridge Road in Parma. Sometimes it works, he said.

"Civil War" started a trend of universe-spanning crossovers that Marvel drew up every few years, said Josh Harlan, owner of Imaginary Worlds Comics.

"When I was a kid crossing over was a big deal" because it rarely happened, he said. Today crossovers occur almost annually.

Marvel released a "Civil War II" storyline that began in June 2016, and an "Inhuman vs. X-Men" series concluded in March. Having so many diminishes their impact, Harlan said, and some fans resent having to buy titles they aren't usually interested in if they want the full story.

The sheer number of Marvel titles is also a problem, North Coast Nostalgia manager and longtime employee Adam Barsa said.

For example, the iconic mutant superhero team the X-Men -- who are the subject of a successful series of movies -- now have seven ongoing titles. And in the early 2000s Marvel released and Ultimate line of comics that stars classic superheroes, but takes place in a different fictional universe.

"They're giving each individual 'Guardians of the Galaxy' character their own book," Barsa said, referring to a zany space fantasy series that was recently made into a successful movie franchise. "They're cannibalizing their own numbers. People will pick up the new books, but then they drop the old books."

If fans feel like they're being taken advantage of, they'll stop buying a title, Harlan said.

Graphic novels, which sometimes collect several issues of an ongoing comic book series, have seen a recent spike in popularity. Graphic novel sales rose 12 percent in 2016 over the previous year, even as sales of traditional books remained stagnant.

When many ongoing comic book titles that are popular today got their start, a single issue would tell one story. Today a story spans several issues, and story arcs have been known to span several years worth of issues.

Comic-book store owners and managers said some fans buy graphic novels that collect several issues of an ongoing series rather than the individual issues.

A handful of Cleveland stores -- Ground Zero and John and Carol's among them -- have shelves filled with graphic novels

And then there's the simple fact that comic-book readers have more options outside of Marvel and DC Comics.

A diversity of titles

Major titles like "Superman" and "X-Men" still comprise most of their sales, comic book store owners and managers said.

"Marvel and DC are our bread and butter, that is what we pay our bills on," Barsa said.

But in recent years they've seen a rise in the sales of lesser-known comics, especially those that don't involve superheroes.

"There's such diversity in comics and the clientele that you have to carry stuff that caters to everybody," Harlan said. "Back when I was a kid it was the superheroes and that was it.

"Now, if you're a fan of crime noir, there's crime-noir comics. If you a fan of horror, there's horror comics, he said. "There's tons of science fiction and fantasy. Anything you can think of there's a comic book out there for you."

One reader who relishes in that diversity is Kevin Hornsby of Cleveland.

Hornsby said he frequents B & L Comics in Parma and John and Carol's Comic Book Shop in Kamm's Corners and mostly reads horror comics. Some of the titles he reads aren't well-known to a mainstream audience, but Hornsby said he enjoys comics that star iconic Japanese movie monster Godzilla.

"I've never been a huge superhero fan, but I love the art form and the storytelling format" of comic books, he said.

Horror comics like "The Walking Dead" -- the inspiration for a hugely successful TV series on AMC that takes place during the zombie apocalypse -- sell especially well among titles that don't come from Marvel and DC Comics.

The success of "The Walking Dead" led to a resurgence in independent comic book titles, Barsa said.

"Image (Comics) does really well with their independent stuff," said Ground Zero Comics and Cards owner Marcus Benn, referring to a comic book publisher founded by well-known illustrators that has a strong reputation among fans. "The Walking Dead" is one of their titles.

That and "Saga" -- which Benn described as a grown-up version of the famed space fantasy franchise "Star Wars" -- sell especially well among lesser-known titles, he said.

"They'll never get the same readership as the main Marvel and DC titles," Barsa said. "But some of their better selling books are right on par with the lesser selling Marvel and DC books."

With so many options, some stores said they can't stock every title, and as a result, comic-book store owners said they often cater to a specific subset of readers.

"This is becoming more of a boutique industry," Barsa said. "There are so many books out there, I can't even order a copy of every title that's released on a monthly basis when you count in all the independent books."

In addition, a greater number of titles that star well-developed female and minority characters have brought more readers into the fold, Benn said.

"Forty percent of the readership is female now," he said. "Up from almost zero"

Candace Horn, a frequent customer of North Coast Nostalgia, said she reads comics like "Dollface" -- a series about a 17th century woman who inhabits the body of a doll and hunts witches in 21st Century Boston -- and "Zombie Tramp" -- which follows a sentient female zombie with supernatural powers.

"There are a lot more female characters being highlighted in comics than before," she said. "Before it was a lot of side characters, or somebody there literally just to be eye candy. Plus there's a lot more strong female writers."

Impact of superhero movies

Anyone raised in the 2000s or 2010s may find this hard to believe, but there was a time when movie studios shied away from superhero films that didn't involve Batman or Superman.

Movies starring Marvel Comics characters in the 1980s and 1990s were spectacular flops. A 1989 movie starring vigilante anti-hero The Punisher failed to make enough money to justify a sequel and earned terrible reviews. A "Captain America" movie was released the next year to the universal condemnation of critics and made just $10,000 at the box office, an embarrassingly small sum regularly surpassed by independent films that aren't given a wide release.

And then a Bryan Singer-directed "X-Men" movie hit theaters in 2000 and made nearly $300 million, proving that comic-book movies aren't a niche market. The number of comic-book adaptations has skyrocketed since then. This year alone has already seen the release of "Logan" -- a movie starring a popular "X-Men" character -- and "Thor: Ragnorak," "Wonder Woman," "Guardians of the Galaxy: Vol 2" and "Justice League" are all set to hit theaters in 2017.

But those movies have little, if any, impact on the sales of the books they're based on, comic book store owners and managers said.

Publishers like to promote the movies using the comic books. In fact, local comic-book store owners said DC and Marvel, which are respectively owned by Time Warner and Disney, at times seem more interested in marketing the movies than the comics.

"As soon as the 'Suicide Squad' movie came out, every DC title had to have Suicide Squad splashed all over it," Harlan said. "The problem is there's nothing the other way around. When you go see 'Suicide Squad' in theaters, they don't say, 'Hey, go to your local comic book store and check out this book.'"

A title might see a temporary bump, but rarely inspires new fans, Barsa said.

"People who watch the movies or the shows may come in and pick up one book, but they're not a sustainable market," he said.

An earlier version of this article misidentified the fictional hero Nightwing. He is a DC Comics character, not a Marvel Comics character.