Marvel’s Thunderbolts* redefined what audiences expected from a team-up movie, and a huge part of its success comes from its villain. Rather than facing off against another grounded government operative or rogue soldier, the Thunderbolts were pitted against the unstable power of Sentry and his destructive alter-ego, the Void. The original plan, however, would have been far less effective.

Thunderbolts* brought together a disparate troupe of anti-heroes and reformed villains from across the MCU timeline. Among their ranks was the seemingly innocuous Bob, soon revealed to be Sentry/the Void. This villain wasn’t just terrifying and imposing, but the perfect choice for the movie’s central themes. He’s certainly a far better fit than the original villain choice.

Marvel’s Original Villain For Thunderbolts* Explained

In early development, Marvel Studios considered making John Walker, AKA U.S. Agent, the main antagonist of Thunderbolts*. Writer Eric Pearson explained in an interview with Screen Rant that Valentina Allegra de Fontaine would have manipulated Wyatt Russell’s John Walker into thinking his Super Soldier serum was “wearing off.” Val would have then enhanced his powers to terrifying levels.

As seen in Thunderbolts*, Walker is certainly a compelling character. He’s a flawed soldier struggling with his moral code, anger issues and bitterness. He’s also desperate to redeem himself after his murderous actions in a standout episode of the MCU’s The Falcon and the Winter Soldier.

As a villain, Walker would’ve kept the story small and familiar, focusing on political conspiracies and ideological clashes. This would have reduced Thunderbolts* to yet another mission against a government-backed adversary rather than the more cosmic, emotional allegory that made the final movie stand out. Read Pearson’s full comments below:

ScreenRant: One thing I love about this movie is that it has a deep message about mental health. I love that the climax of this film is really an emotional one. Was it written specifically to represent depression, or was it meant to more broadly be a symbol of internal struggles?

Eric Pearson: “That’s hard to answer because I wasn’t really thinking about theme in the moment. The original drafts of this had John Walker as the punching villain at the end. The idea was that part of Val’s manipulation was that she had told him that his serum was wearing off, and she was doing these medications to keep him going. In reality, he was a time bomb; a Hulk kind of thing. There was going to be a bit of a “Sun’s getting real low” moment because from the beginning of this, it was like, “I want to end our third act fight with a hug.”

That version was kind of fun, but ultimately didn’t work and didn’t feel right tone-wise. I had already kind of layered in the whole Breakfast Club thing, so I was like, “I want someone that they can’t beat in a punching fight and that they have to connect to in an emotional way.”

But back in the Marvel Writers program that I did in 2010 or 2011, I’d read the Sentry comics. In the comics, it’s like the golden God of Good vs. Pure Evil. But I was like, “What if it’s heroic ambition and self-esteem versus self-loathing and depression and loneliness?” He’s basically the entire journey for our heroes rolled into one enтιтy. So, I put him in, and he fit so perfectly. Then it was all about finding and defining the Void space and stuff like that.

It’s one of those things that’s similar to Zemo, where the story in the comics is that the Sentry has so much power and is so great… He existed since the Golden Age and then realized he was a threat, so he erased his memory from everyone. It’s such a fun comic book idea that’s not going to translate into this movie very well, but you want to take as many elements as you can.

We took the memory loss, the duality of his character, and the fact that he was an experiment gone wrong. You want to just take as much to honor the comics, and then fit it into the movie world in the best way. And I take a lot of pride in that because it’s a hard thing to do and figure out the right way, so it doesn’t seem forced.”

Why Sentry And The Void Were The Perfect Villain For Thunderbolts*

By choosing Sentry and the Void, Marvel gave Thunderbolts* a villain who wasn’t just powerful, but meaningful. The Sentry embodies overwhelming strength coupled with fragile humanity, and the Void represents the darkness lurking inside him – an allegory for depression, trauma, and inner demons. This made him a perfect mirror for the Thunderbolts themselves.

Each member of the Thunderbolts team is a deeply flawed character wrestling with regret, moral compromise, and their own fractured sense of idenтιтy. As a result, they could see part of themselves reflected in Sentry’s struggle. This elevated the movie beyond a standard superhero-versus-supervillain showdown into something far more impactful.

It gave the final battle real emotional stakes, representing the whole group confronting the darkness within themselves, and finding solace with each other. Had John Walker been the villain, the film would have lost all this thematic richness. Thankfully, Marvel chose a villain that resonated on a deeper level, ensuring Thunderbolts* became one of its most layered and daring projects.