HOLLYWOOD, CA - SEPTEMBER 21: Actress Rhona Mitra attends the Impact Africa Fundraiser at Sunset Gower Studios on September 21, 2015 in Hollywood, California. (Photo by Paul Archuleta/FilmMagic)

Rhona Mitra Cast in Villain Role for Supergirl Season 4

Rhona Mitra has been cast for the upcoming fourth season of The CW‘s hit Supergirl in the villainous role of Mercy Graves, Lex Luthor’s longtime bodyguard, and she is joined by Robert Baker, who will be portraying her brother Otis, according to Deadline.

Following the imprisonment of Lex, which happened years prior to the series, and Lillian Luthor, the villainous side of the Luthor family is left open, with Graves stepping in to take charge and lead the “human-first” movement, with her brother Otis acting as her right-hand man, using his skills as an alien assassin. Though Graves initially debuted on Superman: The Animated Series in 1996, she made her comic debut the same year, whereas Otis only appeared in the Christopher Reeves films.

Mitra is best known for her work on Cinemax’s Strike Back, TNT’s The Last Ship and for her recurring role on the final season of FX’s The Strain. Baker is most notable for his roles in ABC’s Grey’s Anatomy and Netflix’s Santa Clarita Diet.

Season 3 saw Supergirl stop Reign and the other Worldkillers’ threat to humanity and our planet, and in the process, Kara was shocked to find her mother Alura alive and living in a salvaged Argo City that survived the destruction of Krypton. Reconnecting with her past caused Kara to realize that her true home is now here on Earth, where big changes are taking place for her and all of her friends in National City – and also, it appears, for a doppelganger in Russia! Season four promises to be full of surprises, action, adventure and lots of big revelations for Supergirl, Alex, James, J’onn, Lena and Brainy.

Supergirl stars Melissa Benoist as Kara Danvers/Supergirl, Mehcad Brooks as James Olsen, Chyler Leigh as Alex Danvers, Jeremy Jordan as Winslow ‘Winn’ Schott, Katie McGrath as Lena Luthor, Jess Rath as Brainiac 5, and David Harewood as Hank Henshaw/J’onn J’onnz. New to the cast for the fourth season is Sam Witwer as hero Agent Liberty.

Based on the DC characters created by Jerry Siegel and Joe Shuster, the series is executive produced by Greg Berlanti, Sarah Schechter, Robert Rovner and Jessica Queller. Supergirl is produced by Berlanti Productions in association with Warner Bros. Television.

(Photo Credit: Getty Images)