New images from Monday's episode of "Supergirl" reveal a new villain in the form of Dichen Lachman's Roulette, and a new alien threat.

In the episode, titled "Survivors," Kara, Alex and the DEO investigate an underground fight club in which aliens duel to the death for the amusement of its ruthless ringleader.

Supergirl -- Survivors -- Image SPG204b_0225 -- Pictured: Melissa Benoist as Kara/Supergirl - Photo: Diyah Pera/The CW -- © 2016 The CW Network, LLC. All Rights Reserved

The photos showcase Roulette, complete with snake tattoos, holding court over the combatants. The DC Comics character is known as a master tactician who loves the danger of a good game, especially if she profits from it. She's is also known to be skilled in hand-to-hand combat. Between a monstrous new alien and Roulette, it appears as if Supergirl and Martian Manhunter will have their hands full battling to uphold the new alien amnesty law put in place in the previous episode by the U.S. president, played by guest star Lynda Carter.

"Survivors" also finds Hank coming to terms with the knowledge that there's another Martian on Earth. Additionally, the photos feature more time for Alex and Maggie Sawyer (Floriana Lima) and a training session for Daximite Mon-El (Chris Wood). Supergirl finds herself in a mentor role for the apparent last son of Daxom, the sister planet to Krypton.

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Airing Mondays at 8 p.m. ET/PT on The CW, "Supergirl" stars Melissa Benoist in the title role, David Harewood as Martian Manhunter, Mehcad Brooks as Jimmy Olsen, Chyler Leigh as Alex Danvers and Jeremy Jordan as Winn Schott.

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