Two more major casting additions have been made to Supergirl, with Homeland's Davide Harewood set to play Hank Henshaw and Grey's Anatomy alum Chyler Leigh cast as Alexandra "Alex" Danvers. This version of the character better known to comic book fans as Cyborg Superman is a one-time CIA agent who now runs the Department of Extra-Normal Operations (DEO), which tracks extraterrestrial threats on Earth. Alex meanwhile is the confident foster sister of Kara. Fascinated by Kara's powers from a young age, Alex developed a lifelong obsession with science that inspired her to become a doctor. Even more exciting than this is the fact that Arrow and The Flash's Andrew Kreisberg has joined Greg Berlanti and Ali Adler as a writer and executive producer. Supergirl focuses on Kara Zor-El, Superman's cousin, who was born on the planet Krypton and escaped amid its destruction years ago. Melissa Benoist will play Kara, who after arriving on Earth was taken in by a foster family, the Danvers, who taught her to be careful with her extraordinary powers.