Warning: This article contains spoilers for Captain America: Brave New World.

Marvel cut a number of characters from the theatrical cut of Captain America: Brave New World, but I’m especially surprised that one new MCU villain in particular wasn’t included in the Phase 5 sequel. Captain America: Brave New World marked the return of several iconic MCU characters, some dating back to the very start of the franchise, such as Samuel Sterns, Thaddeus Ross and his estranged daughter, Betty. Anthony Mackie’s big-screen debut as Captain America introduced a slew of new MCU characters, too, but I was sad to realize some ended up on the cutting-room floor.

Shortly before Captain America: Brave New World’s release on February 14, we were told that wrestler-turned-actor Seth Rollins’ MCU role had been cut. Rollins revealed on INSIGHT with Chris Van Vliet that his role was “either repurposed or completely erased,” and director Julius Onah later confirmed to ComicBook that Rollins’ role was changed when Giancarlo Esposito joined Brave New World’s cast. Seth Rollins wasn’t the only casualty of Captain America: Brave New World’s cuts, however, as I was sad to see another powerful Marvel villain omitted from the Phase 5 sequel.

Marvel Cut Rosa Salazar’s Diamondback From Captain America: Brave New World

Rachel Leighton’s Diamondback Debuted In Marvel Comics Back In 1985

Alita: Battle Angel and Maze Runner star Rosa Salazar was confirmed to have been cast in Captain America: Brave New World in December 2023, and subsequent set photos revealed that she would have sported bright pink hair in the movie. In Marvel Comics, Rachel Leighton’s Diamondback, a powerful member of the Serpent Society, also sported pink hair, so these set photos all but confirmed Salazar’s casting as the formidable snake-themed villain. However, there was no pink hair in sight in Captain America: Brave New World’s theatrical cut, which I’m genuinely shocked about.

Rosa Salazar is a very talented actor who would have made an exciting addition to the MCU, and I would have loved to have seen Rachel Leighton’s Diamondback make her live-action debut. It seems that Seth Rollins’ replacement with Giancarlo Esposito may have changed the function of the Serpent Society in Captain America: Brave New World, meaning there was no room for Diamondback in the movie’s fast-paced narrative. While I could still see a possible MCU future for Rosa Salazar’s Diamondback, I’m sad she wasn’t included in Brave New World.

I Was Really Excited To See Diamondback Debut In The MCU

Diamondback Is One Of The Most Interesting Members Of Marvel Comics’ Serpent Society

I couldn’t wait to see Rachel Leighton’s Diamondback make her MCU debut, as she is one of the most notable and complex members of the Serpent Society in Marvel Comics. Diamondback debuted in Marvel Comics in 1985’s Captain America #310 as a skilled gymnast, expert fighter and keen marksman. She first came into contact with Captain America while working with the Serpent Society, and, over time, formed something of a romance with the Star-Spangled-Man, which culminated in her leaving the Serpent Society and forming her own team before joining SHIELD.

I love a good villain-to-hero transformation story, and Diamondback’s debut in Captain America: Brave New World could have filled this role. This could have even introduced a possible love interest for Anthony Mackie’s Sam Wilson, which is a storyline that hasn’t yet been explored in the MCU, even though Xosha Roquemore debuted as Leila Taylor in Brave New World. Rachel Leighton’s appearance in Brave New World could have set up some exciting storylines featuring the antihero in the MCU’s future, and I hope Marvel Studios still takes advantage of this possibility.

Diamondback Can Still Join The Serpent Society In 1 Possible Upcoming MCU Project

Giancarlo Esposito Has Teased Sidewinder’s MCU Future

Even though Rosa Salazar didn’t make her MCU debut in Captain America: Brave New World, I still think there’s an upcoming opportunity for her to appear as Rachel Leighton’s Diamondback. Back in May 2024, before he was confirmed to be portraying Seth Voelker’s Sidewinder, the leader of the Serpent Society, Giancarlo Esposito revealed at the Phoenix Fan Fusion event (via Legion of Sand) that Sidewinder would be teased in Brave New World and then developed in a new series. While Marvel Studios hasn’t actually confirmed this, I reckon this possible MCU series will introduce more Serpent Society members.

Captain America: Brave New World only introduced us to two members of the Serpent Society: Esposito’s Sidewinder and Jóhannes Haukur Jóhannesson’s Copperhead. Both survived the events of the Phase 5 movie, so it’s very likely that, should Marvel Studios put a Serpent Society series into development, both these villains will return. I think this would be the perfect place for Rosa Salazar to actually make her debut as Diamondback, and this could also see other members of the Serpent Society from Marvel Comics make their first live-action appearances.