With the recent San Diego Comic Con trailer for Supergirl’s upcoming fourth season giving little-to-nothing away about the impending adventures of Melissa Benoist’s Maid of Might, we’ve now found out who the ‘big bad’ of the new season will be.

Courtesy of Deadline, it’s been confirmed that Rhona Mitra will be playing none other than Mercy Graves – the longtime ruthless bodyguard of Lex Luthor! The Doomsday actress will be joined in the show by Santa Clarita Diet’s Robert Baker as Otis, Mercy’s brother.

The official blurb on these additions reads:

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.

Much like Harley Quinn was created for Batman: The Animated Series, Mercy Graves as a character was created for Superman: The Animated Series. Since then, Graves has gone on to become a fixture of the comic book world. As for Otis, he first appeared in 1978’s Superman: The Movie, played by Ned Beatty.

For Season 4 of Supergirl, the early word is:

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 realise 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 4 promises to be full of surprise, action, adventure and lots of big revelations for Supergirl, Alex, James, J’onn, Lena and Brainy.

Supergirl’s fourth season will premiere on The CW on October 14th. The new season’s UK premiere date has yet to be confirmed at this page.