Melissa Benoist Kara Danvers, Supergirl Actor Chyler Leigh Alex Danvers Actor Mehcad Brooks James Olsen Actor David Harewood Hank Henshaw Actor Katie McGrath Lena Luthor Actor Jesse Rath Querl "Brainy" Dox, Brainiac 5 Actor Nicole Maines Nia Nal, Dreamer Actor April Parker Jones Colonel Lauren Haley Actor Sam Witwer Agent Liberty Actor Grant Gustin The Flash Guest Star Stephen Amell Green Arrow Guest Star Tyler Hoechlin Superman Guest Star Greg Berlanti Executive Producer Allison Adler Executive Producer Andrew Kreisberg Executive Producer Sarah Schechter Executive Producer Jesse Warn Director Marc Guggenheim Writer Derek Simon Writer Robert Rovner Writer