Okay movie fans you know Giancarlo Esposito right? The guy is a legend at playing villains. Gus Fring Moff Gideon... the list goes on. Well guess what? He's now part of the Marvel Cinematic Universe as Sidewinder in Captain America: Brave New World. But here's the twist: he wasn't always supposed to be Sidewinder!
King Cobra? Giancarlo Esposito Reveals He Was Initially Cast as a Different Serpent Society Villain
Turns out Marvel had a different snake in mind for Giancarlo. In a recent interview he spilled the beans that he was originally approached to play King Cobra! Yep that's right King Cobra. Producer Nate Moore apparently talked to him about bringing Klaus Voorhees's alter ego to life.
Esposito himself was pretty hyped about the King Cobra idea. He even joked about how fans already call him "King" in real life which he thought was a cool connection. "If I'm walking around the neighborhood African-Americans go 'What's up King?' I love it. They call me King baby! I mean that's the highest honor" he said.
So what changed? Well Marvel being Marvel they were digging deep into the comics. They realized there were already a few "Kings" running around in the Marvel world and King Cobra had ties to the Serpent Society. They wanted to make things fit just right in the MCU. That’s when Nate Moore came back to Esposito with a change of plans.
Sidewinder Switch-Up: From King Cobra to Master Mercenary in Captain America: Brave New World

Instead of King Cobra Marvel decided to go with Sidewinder for Esposito. Sidewinder also known as Seth Voelker is still a pretty cool villain. He is a mercenary crime boss who leads the Serpent Society in the comics. His backstory is that he was an economics professor who got mixed up with Roxxon Oil Company and some chemical mutations.
Esposito explained that the switch to Sidewinder happened during the movie's reshoots. Marvel wanted to "ground the movie" a bit more and Sidewinder was seen as the character to do that. They envisioned him as a "really grounded in a mercenary fashion" type of villain. For Esposito it was a bit of a "whirlwind" but being the pro he is he focused and "knocked it out."
Hopes for the Future: Giancarlo Esposito Wants to Stick Around the MCU a Little Longer

Even though Sidewinder might not have been the original plan Giancarlo Esposito seems to be on board with his MCU journey. He mentioned he is "hoping to be in this universe a little longer." Sidewinder does survive Captain America: Brave New World so there is definitely potential for him to pop up again.
Maybe we'll see more of the Serpent Society in future MCU projects. Perhaps Sidewinder will become a bigger menace down the line. Esposito definitely has the talent to make Sidewinder a memorable MCU villain. It sounds like even though the role change was unexpected he is ready to embrace whatever Marvel has in store for Sidewinder.
Captain America: Brave New World - Box Office and Fan Reactions

Now let's be real Captain America: Brave New World has had a bit of a mixed reception. Critics scores are not sky-high and box office numbers while decent are not exactly breaking records. It has made around $372 million worldwide but compared to other MCU giants it is on the lower end. It currently sits at a 48% score on Rotten Tomatoes which is on the lower side for Marvel movies.
What Does This Mean for Giancarlo Esposito's MCU Villain?
Even with the mixed reactions to the movie Giancarlo Esposito's casting and potential future in the MCU remain interesting. The fact that Sidewinder wasn't the initial plan and was kind of slotted in later might explain why his role in Captain America: Brave New World feels a bit secondary. But Esposito is a strong actor and he has definitely made Sidewinder intriguing even with limited screen time.
Hopefully Marvel will find a way to use Giancarlo Esposito's talents and give Sidewinder a chance to really shine as a major MCU villain in the future. Maybe in a Serpent Society focused project or a Captain America rematch? We will have to wait and see but Esposito definitely seems eager for more.