Julius Onah Hints at Giancarlo Esposito’s MCU Return: ‘That Lane Is Left Open for a Reason’

Giancarlo Esposito recently made his MCU debut in Captain America: Brave New World as Sidewinder, the leader of the Serpent Society. His character was introduced during reshoots, replacing Seth Rollins’ King Cobra. While the Serpent Society’s role in the film was reduced, Esposito’s character remained one of the most significant additions to the movie.

Now Julius Onah revealed how Esposito got added to the movie, and what fans can expect in the future.

Onah explained that while it might seem like Giancarlo Esposito’s character, Sidewinder, was completely new and added during reshoots, the Serpent Society was always part of the film’s story. What changed was how they were presented to better fit the movie’s grounded tone.

Originally, the Serpent Society may have leaned too much into their comic book origins—characters dressed as snakes with exaggerated, snake-like abilities—which didn’t quite match the more realistic approach of the film.

Since the movie features actors like Anthony Mackie and Harrison Ford, who naturally bring a sense of realism to their performances, the filmmakers decided to adjust how the Serpent Society fit into that world.

Instead of changing the group’s role in the story, they reworked how they were introduced. Sidewinder, historically the founder of the Serpent Society in the comics, was brought in as a way to keep the group’s presence grounded while still allowing for some of the fantastical elements. When Giancarlo Esposito became available for the role, it was an easy decision to bring him in.

You know, they are people dressed like snakes in comic books, and they have snake-adjacent powers and stuff that’s really, really heightened, and you wanted an actor who could really help us lean, or gesture towards the fantastic, but without losing that sense of grounding.

So it’s not like Serpent Society or the character changed. It was just, let’s really introduce a version of them that fits into the tone of the movie. And Sidewinder has historically been the founder of Serpent Society. So that was also another detail that we wanted to weave into it, since it’s our first time seeing them in the MCU. And when Giancarlo was available, hell yeah!

Onah also wanted Sidewinder to have a commanding presence, almost like a warlord who inspires deep loyalty from his followers. To build this character, they drew from real warlords in places like the Congo, blending that influence with the concept of a mercenary leader. This approach helped make Sidewinder and the Serpent Society feel more believable in the film’s grounded world.

Onah compared this process to how they handled The Leader, another villain in the movie. In the comics, The Leader has telekinetic abilities, but during development, they decided to focus more on his intellect as a formidable adversary rather than his powers. These types of adjustments may seem drastic from the outside, but Onah reassures that every change was carefully considered to fit the film’s tone.

Onah didn’t confirm whether Giancarlo Esposito’s Sidewinder will return in future MCU projects, but he strongly hinted at the possibility. When asked about it, he simply said, “That lane is left open for a reason,” suggesting that the character’s story isn’t necessarily over. While he didn’t provide any details, his response implies that Marvel has plans—or at least the option—to bring Sidewinder back down the line.

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