'Supergirl' Casts Lex Luthor's Bodyguard Mercy Graves as Season 4 Villain

With the evil Luthors in prison and Lena Luthor helping out the good guys, there's a void in Supergirl for a truly devious mastermind. But one of Lex's old associates is going to step up in Season Four of The CW series.

Lex's former bodyguard Mercy Graves will be a recurring threat on the new episodes, played by Rhona Mitra. Her brother Otis Graves will also be by her side, played by Robert Baker, according to a new report from Deadline.

The new report offers some information on the new characters, revealing that Graves has come into her own as a growing name in National City now that her former employer Lex Luthor is in prison. She becomes the face of the growing "human first" movement, teasing that the series will echo the current political climate in real life.

Given the fact that she used to be Lex's bodyguard, she's very lethal. But she'll also be very cunning, making her a threat to Supergirl on multiple levels.

Otis Graves will be her enforcer, who isn't as smart as his sister but is described to have "savant-like abilities to assassinate aliens," according to Deadline. He has not appeared in the comic books, but was created for Superman: The Movie by Richard Donner.

It's likely these characters could run afoul of Lena Luthor, but maybe by the end they could be responsible for helping her embrace her family's nature and lead her to become an enemy of her good friend Kara Danvers' heroic alter ego.

Mercy Graves also appeared in Batman v Superman: Dawn of Justice, played by Tao Okamoto in the film.

Mitra previously appeared on The Last Ship as Dr. Rachel Scott and was in the Netflix original movie Game Over, Man as an assassin, teaming with another Arrowverse alum Neal McDonough.

Baker had recent stints on Grey's Anatomy and the Netflix series Santa Clarita Diet.

The two actors join a bevy of new faces coming to Supergirl in Season Four, all of whom are likely to make her life much harder.

The series also cast David Ajala as the telekinetic super villain Manchester Black. In the comics, Manchester Black masqueraded as a superhero alongside his allies in the Elite, who helped turn public opinion against the Justice League before enacting their evil schemes. Expect to see a variation of that storyline in Supergirl.

Star Wars alum Sam Witwer is also joining the cast as Agent Liberty, the leader of a human-first hate group that will create trouble for Supergirl and the DEO.

With the villains piling up, it looks like the Girl of Steel will have her hands full in the new episodes.

Supergirl will return to The CW for Season Four later this fall on October 14th.