'Avengers,' the Most Lucrative Movie Franchise Ever, Is Wrapping Up. Why?

BURBANK, Calif. — Everything ends, even if it might not feel that way right now for Joe and Anthony Russo. More than a year into the making of “Avengers: Infinity War,” these directing brothers were shuttling around the Walt Disney Studios here one evening in March, putting the finishing touches on their latest superhero blockbuster.

The tasks that awaited them were mostly routine and unglamorous: rerecording dialogue with Elizabeth Olsen, who plays the Scarlet Witch; taking their last looks at a new trailer for the film, which opens Friday and sets up a battle royal in which every costumed champion in the Marvel universe must defend it against a genocidal titan named Thanos.

With these duties out of the way, the Russo brothers have one more assignment to complete: successfully bringing the curtain down on the most lucrative franchise in Hollywood history.

The 18 movies that preceded “Infinity War” were a risky feat unto themselves: a multihour narrative in which each installment handed off to the next — sometimes elegantly, sometimes awkwardly — and events in previous episodes had lasting effects on those that followed.

Now Marvel is trying something equally unprecedented and potentially far riskier. In “Infinity War” and a subsequent “Avengers” movie that will open in May 2019, the Russos need to seamlessly incorporate dozens of major characters, all while bringing the franchise to a satisfying conclusion.

“We’re not making any bones about the fact that we’re ending the first 10 years,” Joe Russo said later that night. “That’s what we pushed for.”

This was hardly the outcome that the entertainment industry anticipated when the Marvel studio kicked off its current campaign in 2008 with “Iron Man” (considered a second-tier character at the time, but one of the few whose rights it controlled).

A decade later, the runaway success of that film laid the foundation for a pantheon of Marvel movies, including “Captain America,”“Thor” and “Guardians of the Galaxy.” These films revitalized the careers of enduring actors like Robert Downey Jr. (as the billionaire industrialist Tony Stark, a.k.a. Iron Man) and raised the profiles of relative unknowns like Chris Evans (as the supersoldier Steve Rogers, alias Captain America).

The studio has breathed lucrative new life into its decades-old comic-book properties, and built a ravenous fan base for each new character it introduces at the multiplex. (Witness the $1.3 billion global box office for its latest hit, “Black Panther,” which opened in February.)

Now Marvel says it wants to clear the table it has spent the last 10 years arranging and make way for something new.

“Telling a great story requires a great ending,” Kevin Feige, the Marvel Studios president, said. “When you dedicate yourself to that, it shifts the way you think.”

Audiences are about to find out what finality looks like for a motion-picture money-minting machine: Will the story actually come to a conclusion? Will characters die, and will actors leave the series?

Whatever the answers, they have already been reached with the help of the Russo brothers, two of Marvel’s most consistent and diligent — if not widely recognized — filmmakers.

When they finish their “Avengers” movies, which they shot back to back over 18 months, the Russos will complete their own improbable arc, from indie-cinema oddballs to TV comedy moguls to directors of possibly the biggest franchise in movie history.

The brothers — Anthony, 48, the bespectacled brainstormer, and Joe, 46, the square-jawed pragmatist — have contrasting but complementary energies. As Mr. Downey described them, Anthony is “a bit more reflective, a yin guy,” while Joe is the intense yang of the partnership: “Bitcoin was invented to keep Joe Russo from killing himself during the last 20 percent of the shoot,” Mr. Downey said.

When they’re together, Mr. Downey added, “It’s like the two of them make a third thing that’s better than any one person could be.”

The Russos grew up in Cleveland, where their father, Basil M. Russo, served as Democratic majority leader of the City Council. When the city went into an economic tailspin in the 1970s and ’80s, the brothers immersed themselves in movies and learned to appreciate their creative isolation.

As Anthony Russo explained it, “The virtue of growing up in the industrial Midwest is you have nothing to rub up against you and no one to tell you that you can’t do what you want to do, because nobody’s doing anything. You can just be a dreamer.”

They spent three years and $30,000 writing and directing an independent feature, “Pieces,” about three brothers — also named the Russos — who dabble in crime. Despite some withering reviews — Variety called it an “unabashed vanity project” — “Pieces” caught the attention of Steven Soderbergh at the 1997 Slamdance Film Festival.

With his help, the Russos made their first studio movie, a comic crime caper called “Welcome to Collinwood,” with George Clooney, William H. Macy and Sam Rockwell. But it flopped at its release in 2002.

For the next several years, the Russos focused on directing television shows, including “Lucky,” a short-lived FX series, and “Arrested Development,” the rapid-fire satire that became a cult hit on Fox.

Despite critical acclaim, “Arrested Development” got notoriously low ratings. But the Russos said this lack of attention was a blessing in disguise, allowing them to experiment with narrative, tone and pacing, unencumbered by interfering network executives.

“They so didn’t get the show that they really didn’t care what you did,” Anthony Russo said, adding, “It was a huge creative upside.”

The Russos used NBC’s “Community,” another well-reviewed comedy with a meager viewership, to stage elaborate tributes to “Star Wars” and the spaghetti westerns of Sergio Leone. It was here that their work caught Marvel’s attention.

At the time, the studio was generating hits with its earliest superhero offerings, made by established filmmakers — “Iron Man,” directed by Jon Favreau; “Captain America: The First Avenger,” directed by Joe Johnston. But Marvel wanted to expand its portfolio rapidly and bring in TV directors.

Marvel also wanted to shift the tone of its “Captain America” movies, starting with the 2014 sequel, “The Winter Soldier.”

“The first one was a fairly patriotic, gung-ho World War II movie,” said Christopher Markus, who wrote the “Captain America” films with Stephen McFeely. “You can’t make a string of those before you get slightly nauseous.”

The goal of “The Winter Soldier,” Mr. Markus said, was to show Captain America “losing faith in all the institutions that had made him, giving you a way to see him as relevant in the modern era.”

The Russos envisioned “The Winter Soldier” as a modern-day upgrade of espionage thrillers like “Three Days of the Condor,” and the studio responded strongly. When the movie sold $714 million in tickets worldwide, Mr. Feige said the Russos “redefined the franchise — not just the Cap franchise but all the Marvel movies going forward.”

“They found a way to keep the wonder, keep the spectacle, but ground it even more in realism,” Mr. Feige said. “Which is a word I use lightly when it comes to our movies.”

The Russos succeeded again with “Captain America: Civil War,” an overstuffed 2016 sequel in which the Black Panther (Chadwick Boseman) and a new incarnation of Spider-Man (Tom Holland) were introduced, and the adventurers took sides in a conflict between Cap and Iron Man.

Even before “Civil War” became a $1.15 billion global smash, Marvel had already started putting the pieces in place for what Mr. Feige called “the big finale of the initial story line we were developing.”

The plan was ambitious: Mr. Markus and Mr. McFeely would write two “Avengers” movies, generated from a 60-page manifesto they started working on in 2015. All the major Marvel heroes had to be accommodated, and still more characters would be introduced. “Not every scene can be 25 people in a room,” Mr. McFeely said. “You’re going to have to make kickball teams and then have a tournament.”

With scripts in hand, the Russos would film these movies consecutively. In Mr. Feige’s mind, there were no other directors who could handle the task of doing “ three straight years of filmmaking.”

Mr. Feige said, “There are two of them, which helps. But their individual stamina is unmatched.”

The Russos moved from Los Angeles to Georgia for two years, where “Avengers: Infinity War” and its sequel were shot, principally at Pinewood Atlanta Studios. (They estimate that they took a break of about three weeks between filming the two movies.)

They said making the movies this way was an irresistible challenge — one that has been attempted by very few directors, including the Wachowskis (“The Matrix” series) and Peter Jackson (the “Lord of the Rings” and “Hobbit” franchises) — and a test of their fortitude.

Describing the process, Anthony Russo said, “You’re a really good marathon runner and you know how to train for it. All of a sudden, you’re running a double marathon. You can’t really understand it until you do it.”

The Russos acknowledge that the films were made this way, in part, for economic reasons: it’s cheaper for Marvel to hire actors — dozens of them, some of whom are very costly — for months at a time, rather than make individual deals for each movie.

Though they must serve many corporate masters at Disney and Marvel, and Mr. Feige is known for having a strong hand in his films, the Russos say they were given the latitude to make the movies they want to make.

“It’s no different than making any kind of narrative in a medium where capitalism thrives,” Joe Russo said. “You have to have a Zen resilience about what it is that you want to do, and then do a really good job at it. And everybody stays out of your hair.”

Mr. Downey, who first worked with the Russos on “Civil War,” said they were well served by their TV training, which has taught them to be quick and collaborative.

At any given moment on these films, Mr. Downey said, “we’ve got 80 things that are going to blow up, collide — story points that are all about to happen at once.” When one of the Russos had a new idea, he said, they would approach him with a gentle query: “Let me pitch you this.”

“No one takes it personally, and then the idea emerges,” Mr. Downey said. “It ends up an amalgam of everything that didn’t hit the floor.”

The Russos aren’t revealing much about how, exactly, their “Avengers” movies will bring closure to this phase of the Marvel cinematic saga. (They wouldn’t even disclose the title of the movie that follows “Infinity War,” protesting that even this much information would be a spoiler.)

“Ultimately,” Joe Russo said, “what you’ll see by the end of the movies is, what does it cost to be a hero in a world where there are no easy answers? I think that’s the world we live in.”

Death is a staple of comic books. Beloved characters are killed off all the time, sometimes replaced by successors who inherit their costumes and identities: Bucky becomes the new Captain America; Jane Foster the new Thor. There’s no reason to believe that their motion-picture counterparts aren’t similarly mortal and similarly interchangeable.

Mr. Evans has made no secret of his desire to move beyond the “Captain America” movies. Meanwhile, Mr. Downey — who introduced himself in a phone interview as “Robert Downey Jr., retired film actor” — is already working on his next prospective tentpole movie, “The Voyage of Dr. Dolittle.”

He talked about his time with Marvel in retrospective tones, and reflected on an encounter with Keanu Reeves, who at the time had just finished making the first “Matrix” movie.

“I was like, ‘Hey, dude, how’d it go?’” Mr. Downey recalled. “He said, ‘I’ve been on another planet.’ Right now, I’ve been on the planet Dolittle for a while. Being detached from it has given me a lot of warmth, affection and objectivity about this past decade.”

Of course, the Marvel engine will keep chugging away. “There will be more movies with some of these characters,” Mr. Feige said, “and with lots of new characters.”

Disney’s pending acquisition of Fox would add even more familiar heroes to Marvel’s toy chest, including the X-Men and Fantastic Four. But Mr. Feige said it was “way too soon” to make plans for these properties.

“We’d love to have all the characters back,” Mr. Feige said. “It’s a dream. But we’re plenty busy with the next five films.”

The Russos, too, are preparing for their post-“Avengers” lives. They have established their own production company, Agbo Films, whose executives include Mr. Markus and Mr. McFeely and which has already secured $250 million in private Chinese funding.

The brothers are elliptical about whether there are more Marvel movies in their future. “We wanted to maximize our options as storytellers and artists,” Anthony Russo said. “We’ve structured our business life in a way to support that. It can be, or it can’t be. We’ve kept all options open.”

Joe Russo said there are still some “very personal projects we want to make,” adding that he and Anthony want to nurture up-and-coming filmmakers just as Mr. Soderbergh did for them. “We owe a karmic debt to the universe because of what Steven did for us,” he said.

The reality, though, is that the Russos are not even finished with “Avengers.” Once “Infinity War” is released, there is still a whole additional movie for them to construct from untold hours of raw footage, a task that they estimate will take them at least until the end of the year. “There are months of work left on it,” Anthony Russo said. “It will be very cathartic for us to come out the other end. That’s when our brains can open up to what’s next.”