Supergirl Season 5 has cast the ancient alien characters Gamemnae and Rama Khan, the two leaders of DC Comics' League of Ancients.

According to Deadline, Stranger Things' Cara Buono will play the role Gamemnae. Meanwhile, X-Files alum Mitch Pileggi has been tapped to step into the shoes of Rama Khan. Both actors will appear on the DC television series in a recurring capacity.

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Alongside the other ancients, Buono's Gememnae has been "safeguarding the Earth from the follies of humanity throughout the ages" and is described as "cunning, witty, ruthless and always ten steps ahead of her adversaries." Her goal is to conquer the humans and bring them to order with the use of technology - a goal that puts her on collision course with Supergirl.

Meanwhile, Pileggi's Rama Khan is described as "arrogant and willful." He possesses the ability to control the four ancient elements -- fire, water, earth and air -- which he has used to to protect the world from mankind for millenia. However, this mission now puts him at odds with not only the Girl of Steel, but also Lena Luthor

Created by Joe Kelly and Doug Mahnke, Rama Khan and Gemamnae first appeared in 2002's JLA #62 and #70, respectively.

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Returning Sunday, Oct. 6 at 9 p.m. ET/PT on The CW, Supergirl stars Melissa Benoist as Kara Danvers, David Harewood as Martian Manhunter, Mehcad Brooks as Jimmy Olsen and Chyler Leigh as Alex Danvers.