By AITechtonic.com – August 2025
When it comes to comic book adaptations and superhero franchises, Robert Kirkman is no stranger to big revelations and passionate fandoms. As the mastermind behind hits like Invincible and The Walking Dead, Kirkman has lived at the intersection of comic lore and pop culture buzz for decades. But one particular moment from 2023 still haunts him to this day—the time he accidentally revealed that actor Steven Yeun was set to play The Sentry in Marvel’s Thunderbolts.
Fast forward to San Diego Comic-Con 2025, and Kirkman is back in the spotlight, promoting his highly anticipated fighting game Invincible VS and offering updates on the fourth season of Invincible. But during an interview with IGN, it wasn’t just future projects that took center stage—Kirkman found himself revisiting a moment he’d probably rather forget.
The Accidental MCU Leak Heard Around the World
To fully understand Kirkman’s hesitancy today, we need to rewind to 2023. At the time, speculation was mounting over who would portray Robert Reynolds, better known to Marvel fans as The Sentry, in the MCU’s Thunderbolts film. The Sentry, a complex and psychologically unstable superhero with godlike powers, had been a fan-favorite pick to join Marvel’s Phase 5 or Phase 6 lineups.
Whispers across Reddit, Twitter (now X), and fan forums suggested that Invincible and Minari star Steven Yeun had secured the role. But there was no official confirmation from Marvel Studios, which is famously tight-lipped about its casting decisions.
Then came Robert Kirkman.
In what appeared to be an offhanded comment during an interview, Kirkman dropped a bombshell that would ignite Marvel fan circles worldwide. Here’s what he said back then:
“Yeah, he [Yeun] called me, he went in for a costume fitting. I hope I’m not… I don’t think this is a spoiler or anything that will get anybody in trouble. I don’t know, maybe. We’ll see. I don’t care. I don’t work for Marvel. What are they going to do to me?”
Kirkman then followed up with a telling anecdote from Yeun:
“Yeah, he called me and he said, ‘I just came back from a costume fitting for The Sentry. I guess I only do superheroes that are yellow and blue.’ He said he was at the costume fitting and was like, ‘Aww, crap. I forgot Invincible was yellow and blue.'”
For a moment, it felt like the secret was out. Yeun, beloved by animation and live-action fans alike, was going to bring The Sentry to life on the big screen. Fan art flooded Instagram, Twitter debates erupted, and even some industry insiders started treating the casting as fact.
The Twist: Yeun Exits, Lewis Pullman Steps In
But as often happens in Hollywood, plans changed.
Months after Kirkman’s “leak,” Marvel officially announced that Steven Yeun would no longer be involved in Thunderbolts. Citing scheduling conflicts and creative shifts, Yeun stepped away from the project. The role of The Sentry eventually went to actor Lewis Pullman, best known for his roles in Top Gun: Maverick and Outer Range.
While Pullman delivered a compelling and psychologically rich portrayal of The Sentry in the 2025 summer release of Thunderbolts, many fans still wondered what Yeun’s take would’ve looked like. Some even speculated that Kirkman’s early reveal might’ve played a role in complicating the situation—though there’s no official word supporting that theory.
SDCC 2025: Kirkman Opens Up (and Jokes About It)
Back to San Diego Comic-Con 2025. Sitting down with IGN to promote Invincible VS and other projects, Kirkman was once again asked about Yeun—specifically, who the actor will be playing in the upcoming animated film The Legend of Aang: The Last Airbender (set for release in late 2026).
Kirkman’s response was quick and self-aware:
“I don’t want to lose any more sleep spoiling Steven Yeun news! I cannot tell you how much that Thunderbolts thing affected me.”
With a chuckle, he added:
“Why would you guys bring that up? I’m so angry.”
It was a moment of levity, but also a genuine peek into the pressures creators face in the modern spoiler-sensitive media environment. As fandoms become more reactive and leaks spread in seconds, even informal comments can create waves that last years.
Kirkman Knows, But He’s Keeping Quiet This Time
Despite the clear boundary he’s drawn, Kirkman admitted he does, in fact, know who Yeun will be voicing in The Legend of Aang: The Last Airbender. But this time, he’s not letting the cat out of the bag.
“The best part is he told me who he’s playing in The Last Airbender and I was like, ‘I wish I didn’t know. I wish I didn’t know.’”
His restraint was met with laughter from the crowd and the interviewers, who knew all too well the weight of his previous slip.
Kirkman even took the opportunity to lean into parody, joking that Steven Yeun will be playing Abraham Lincoln in a fictional live-action adaptation of his latest comic series Skinbreaker, co-created with artist David Finch.
“Steven Yeun as Abraham Lincoln in Skinbreaker. You heard it here first!” Kirkman quipped.
Of course, this was clearly tongue-in-cheek—a way for Kirkman to poke fun at the situation while reminding everyone just how sensitive casting news can be.
Invincible Season 4, Skinbreaker, and More Kirkman Projects at SDCC 2025
While the Yeun drama made for juicy headlines, Kirkman didn’t come to Comic-Con just to relive past blunders. The fan-favorite creator had plenty of major updates to share across his ever-growing empire of superhero content.
1. Invincible Season 4 News
Kirkman confirmed that Invincible Season 4 is deep in production, with Dinosaurus set to play a significant role. The voice actor behind the dinosaur-themed anti-hero was announced (though the studio asked media to withhold the name until the fall).
Kirkman also addressed how many seasons the show will need to complete the comic’s arc:
“We’re looking at around 7–8 seasons to do the comics justice. But it depends on how much support the show keeps getting.”
In true Kirkman fashion, he couldn’t resist joking:
“Season 5 will probably drop in 2032 at this rate.”
2. Invincible VS: The Fighting Game
Fans of superhero brawlers had reason to celebrate as Kirkman showcased Invincible VS, a new 2.5D fighting game inspired by characters from the Invincible universe.
Developed by a top-tier indie studio in collaboration with Skybound Games, Invincible VS will feature characters like Invincible (Mark Grayson), Atom Eve, Omni-Man, Battle Beast, and more—each with unique combat styles and brutal finishers true to the tone of the series.
The game is expected to release in early 2026 on PlayStation 5, Xbox Series X|S, and PC.
3. Skinbreaker: A New Horror-Adventure Comic
Perhaps the biggest surprise of Kirkman’s SDCC showcase was the unveiling of Skinbreaker, a new horror-fantasy comic created with legendary artist David Finch.
Described as a cross between The Witcher and Mad Max, Skinbreaker follows a cursed warrior in a post-apocalyptic land battling ancient gods, rogue witches, and mutated beasts. It’s darker and more mythological than anything Kirkman’s done before.
“It’s very much a love letter to 1980s dark fantasy with a modern psychological twist,” Kirkman said.
A live-action adaptation is already being discussed—though no Steven Yeun as Abraham Lincoln… yet.
The Larger Lesson: Spoilers, Fandom, and Creator Boundaries
Kirkman’s accidental Thunderbolts reveal and his more cautious approach in 2025 represent a broader shift in how creators interact with press, fandoms, and IP holders.
Marvel Studios, Lucasfilm, and other major franchises have created a culture where even a single slip of the tongue can lead to massive media speculation. For creators like Kirkman, who exist both inside and outside these worlds, the line between transparency and confidentiality has never been thinner.
Yet, Kirkman has handled it all with humor, grace, and a keen awareness of his influence. He may have learned the hard way with Thunderbolts, but his Comic-Con showing proves that he’s still a fan-favorite—both for his work and his willingness to own up to past missteps.
Final Thoughts
Steven Yeun’s would-be role as The Sentry may have never come to pass, but it lives on as one of the most memorable casting what-ifs in recent Marvel history. For Robert Kirkman, it’s also a constant reminder that in today’s hyper-connected, spoiler-sensitive world, even casual comments can ripple across an entire industry.
As fans eagerly await more Invincible, The Legend of Aang, and Kirkman’s future work, one thing is clear: whatever Steven Yeun is up to next, Robert Kirkman probably knows—but this time, he’s staying silent.
Disclaimer: This article was written by AITechtonic.com for informational and entertainment purposes. All trademarks and copyrighted materials belong to their respective owners. No affiliation or endorsement is implied.
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