Once it became apparent that Marvel Studios' Iron Man was more than a one-off superhero film, that it was intended to kick off an entire universe of films set in a shared universe, people began to wonder: what happens when Robert Downey Jr. decides he's done playing a superhero?

It's a question that has launched more than a few thinkpieces (including a recent one right here at CBR), and has likely been if not a source of concern at Marvel Studios, at least a topic of semi-frequent discussion. Downey's original contract was no small potatoes, including three Iron Man films and one Avengers movie. He's renegotiated several times since those early days, of course, adding not only several Avengers sequels, but a co-starring role in Captain America: Civil War and a crucial appearance in the upcoming Sony/Marvel co-production Spider-Man: Homecoming. Given Tony Stark's ubiquitous nature in the Marvel Cinematic Universe since debuting in 2008, it's no surprise that the man who heralded the arrival of the Marvel Universe to the big screen has become perhaps its most recognized face.

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Of course, the issue of what to do when Robert Downey Jr. eventually decides to stop re-upping his contract and actually leave Marvel is hardly exclusive to the Iron Man franchise. The mystery surrounding the true status of Chris Evans' deal to portray Steve Rogers, aka Captain America, continues to be of interest to Hollywood pundits and Marvel fans alike. (The most recent chapter in the saga indicates he'll depart the Marvel Cinematic Universe following the fourth Avengers film.) Chris Hemsworth's status as Thor beyond the upcoming Avengers sequels remains unknown, as does how many more times we'll see Scarlett Johansson, Jeremy Renner and Mark Ruffalo (Black Widow, Hawkeye and Hulk/Bruce Banner, respectively) suit up and heed the "Avengers, Assemble" call.

Some of the "solutions" to Marvel's re-casting quandary are practically staring the studio in the face. When Evens eventually leaves the franchise, there are a number of possible solutions as to how to fill Captain America's boots. In the comic book world, both Bucky Barnes (played by Sebastian Stan) and Sam Wilson (played by Anthony Mackie) have taken on the mantle, with the latter recently sharing the identity with Steve Rogers. Stan's contract is rumored to involve at least 4-5 more movies, enough to relaunch the character in a new franchise in a few years. Less is known about Mackie's contract length, but the actor has teased that it's not a small number, leaving the door open for him to possibly wield the shield at some point in the future.

Of course, none of this solves the problem of what to do when Downey or Marvel decide he's too old to armor up any longer. Luckily for Marvel Studios, Marvel Comics has given them a solution that is, frankly, elegant in its simplicity: in order to cement Tony Stark's role as the center of the MCU, all that remains to be done is to kill him.

Wait, what?

We'll get to how the death of its most recognizable character is the perfect way to ensure Tony Stark remains on the big screen in a moment, but first, some back story. First of all, you need to know that in the Marvel Universe, Tony Stark is no longer Iron Man. In the heat of the final battle of Civil War II, a conflict that pitted Tony against Carol Danvers (Captain Marvel) in hand-to-hand combat, he was mortally wounded. While he appeared to have died, it turns out he's merely in a coma, his life apparently being supported by special bio-enhancements. As a result, Tony Stark has essentially been removed from the superhero game. It's a good thing, then, that he had a back-up plan.

With the role of Iron Man now open, a pair of players stepped up to attempt to fill Stark's jet-propelled boots. One is a character we're not likely to ever see grace the MCU with his presence: Doctor Doom, aka the Infamous Iron Man. The other is a newcomer to the Marvel Universe, just begging to be brought to life as part of the MCU: Riri Williams, aka Ironheart, a young genius who developed her own suit of armor from scraps of Stark Tech, catching the eye of Stark before he went into a coma -- and began to mentor her.

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In Invincible Iron Man #1, it was established that while Tony may be in a coma, being a futurist, he had downloaded the sum of his knowledge and personality to an artificial intelligence. As a result, Riri, Pepper Potts and several other characters close to Iron Man, have been interacting with an A.I. that takes the form of a holographic replication of Tony Stark.

It's in this week's Secret Empire #4, however, where the true genius of the concept of A.I. Tony is revealed. Not only has it extended its presence beyond the realm of the lab, it has been going out on missions by inhabiting one of Iron Man's classic armors, and has begun interacting with its fellow superheroes sans helmet, holographic head hovering above the armor's open neck, as though he were the real Tony. Thus, despite his physical body being in lock away in stasis, Tony Stark remains a player in the biggest event to his the Marvel Universe in years, leading the charge and formulating plans to take down evil Captain America's Secret Empire (it's a long story) as though he were a real, live person.

Ever since the MCU launched, Marvel Comics' character have taken cues from their onscreen counterparts, adopting costume changes, personality tweaks and more from the movies to the printed/digital page. With the introduction of A.I. Tony Stark, the movies now have the blueprint for what to do when Downey or Marvel decide the actor's time in the role is up: Renegotiate Downey's contract into one where he provides mo-cap and voice acting for an un-aging, A.I. version of his character. Off the character by having him make the ultimate sacrifice (in the follow-up to Avengers: Infinity Wars, perhaps?), and the door will be open to more Downey/Stark than we'd likely otherwise get.

The previously mentioned Civil War film actually set the stage for a post-Tony Stark MCU populated by his digitally-replicated likeness. In his first scene, Stark debuts new technology that can recreate memories as lifelike, 3-D holograms. Interestingly enough, the technology was never mentioned again after the initial demo, with the implication being it was the specific memory we saw that was relevant to the film's plot rather than the tech itself. And perhaps that was all it was intended to do, but thanks to recent Marvel Comics developments at the hands of creators Brian Bendis, Alex Maleev, Nick Spencer and Leinil Francis Yu, we may be able to look forward to having Robert Downey Jr. as the centerpiece of the Marvel Cinematic Universe for a long time to come.

All Marvel Studios has to do now is kill Tony Stark.