WARNING: This article contains major spoilers for the Season 4 finale of Supergirl, "The Quest For Peace."
Supergirl's Season 4 finale saw the epic final confrontation between the Girl of Steel and Lex Luthor's killer clone of Kara, the Red Daughter. With the hero and villain both wearing power suits, the two characters faced off while Lex Luthor's longterm plans to destroy Argo and Superman neared their fruition.
Celebrating the finale, star Melissa Benoist shared a behind-the-scenes photo of herself wearing Red Daughter's Red Son-inspired power suit while fighting for the fictional nation of Kasnia.
After being used by Lex as a means to turn the world against Supergirl by having her publicly go on a killing spree, Red Daughter was killed by the villain as he defended Supergirl during the Season 4 finale. Her death empowered Kara with enough additional strength to defeat the scheming Luthor and save the day.
Joining Red Daughter in departing the Arrowverse series is Jon Cryer's Lex Luthor, who was killed by his sister Lena at the end of the episode. With two of its recurring antagonists dead, Season 4 served as an ending of sorts, setting the stage for all-new threats moving forward.
Supergirl's fifth season will air on Sundays at 9 p.m. ET/PT on The CW. The series stars Melissa Benoist as Kara Danvers, David Harewood as Martian Manhunter, Mehcad Brooks as Jimmy Olsen and Chyler Leigh as Alex Danvers.