
Marvel Studios has revealed concept art for a comic book character audiences were supposed to see in Captain America: Brave New World. Despite making it into Captain America 4 merchandise, Marvel removed this female villain from the movie's final cut, even though her character's design would've made a fascinating addition to the film.
Marvel Studios' Captain America: Brave New World - The Art of the Movie book contains multiple costume designs for Diamondback, or Rachel Leighton, a female antagonist intended to appear in the 2025 film as portrayed by Alita: Battle Angel star Rosa Salazar. Much like her comic character, Diamondback was a member of the Serpent Society, a villainous comic book group Marvel Studios initially planned for Captain America: Civil War. It's also expected Leighton would've been more of an antagonist than a villain with possible romantic ties to Sam Wilson's Cap.
This newly revealed concept art shows the Captain America: Brave New World design for Diamondback was a blend of comic book inspiration, reptilian influences reflective of the Serpent Society (check out their rumored Captain America 4 mission here), and some grounded yet truly creative artistic choices. For instance, one design shows Rachel Leighton sporting a dark, sleek tactical bodysuit, giving her a more grounded look for Captain America 4.

According to The Art of the Movie book, the design of Rosa Salazar's Diamondback suit is dependent on the daggers she throws and was intended to look a little more techy for the MCU world. But in keeping with her comic book style, she's still sporting her signature pink hair.

Various pieces of concept art also shows different ideas to integrate the character's Diamondback persona and her Serpent Society connections, including designs for gas masks. Marvel Studios art director Michael Uwandi even explored a concept where her high-tech helmet would reflect the snake-haired Gorgon of Greek myth with various tentacle-like wires.

Another idea to showcase her snake-esque style included tattoos that evoked fangs or scales. Uwandi noted some tattoos would've shown wiring within their designs to suggest they served a purpose beyond style alone.

Furthermore, there were ideas for her Serpent Society mask to form from her facial tattoos and create a clear yet scaly design over her face, similar to snakeskin.

Overall, Diamondback's Captain America 4 design could've been creatively intimidating, high-tech, and certainly reflective of the Serpent Society, all while reflecting the character's comic book roots.

While Diamondback was ultimately deleted from Captain America: Brave New World, again, she did make it into some early merchandise, which showed Rosa Salazar's Serpent Society villain with pink hair and a more comic book-accurate suit.
Starring Anthony Mackie, Harrison Ford, Danny Ramierez, and Tim Blake Nelson, Captain America: Brave New World premiered in theaters on February 14, 2025, as part of Phase 5 of the MCU. Directed by Julius Onah, the film followed The Falcon and the Winter Soldier on Disney+ with Mackie's hero investigating a conspiracy involving President Thaddeus Ross (Harrison Ford)
Why Did Marvel Cut Diamondback From Captain America 4?
Captain America: Brave New World endured various rewrites and reshoots throughout production; and despite Marvel Studios' efforts to finally realize this femme fatale, Diamondback was a casualty of the creative process. Just why she ultimately ended up on the cutting room floor is likely due to the film's already crowded call sheet, and the need to center the focus on the conflict between President Ross, Tim Blake Nelson's The Leader (whose design almost included a gross superpower), and Sam Wilson's Captain America.
Still, Marvel Studios did manage to bring a little of the Serpent Society to the screen with Giancarlo Esposito's Sidewinder, the leader of a special-ops team known as Serpent. Whether that means there's still hope for Rachel Leighton in the MCU's future is unknown. Still, from the creativity of these concept pieces, it's clear Marvel artists saw incredible potential for this complicated character, even if she wasn't right for this film.