Even though we have more than three months until Supergirl premieres on CBS, the network has been constantly promoting the superhero TV series throughout the summer. Just one day after a Supergirl trailer surfaced, CBS has unveiled yet another sneak preview, plus a new poster, both of which feature Melissa Benoist as Kara Zor-El. The trailer doesn't feature a ton of new footage, but we do get a glimpse at a very young Kara, wearing a white shirt with the Kryptonian "S" emblazoned on the front.

TV Line reports that the show is adding yet another villain from the DC Comics, Reactron. The villain is described as a, "nuclear-powered, exoskeletal chest-plated madman," who has held a grudge against Kara's heroic cousin Superman, but decides to go after Supergirl instead. It's worth noting that, in the Superman: New Krypton comic books, Reactron is responsible for the death of Kara's parents. We know that Laura Benanti is playing Kara's Kryptonian birth mother Alura Zor-El, but she dies with the destruction of Krypton.

Supergirl is an action-adventure drama based on the DC Comics character Kara Zor-El (Melissa Benoist), Superman's (Kal-El) cousin who, after 12 years of keeping her powers a secret on Earth, decides to finally embrace her superhuman abilities and be the hero she was always meant to be. Twelve-year-old Kara escaped the doomed planet Krypton with her parents' help at the same time as the infant Kal-El. Protected and raised on Earth by her foster family, the Danvers, Kara grew up in the shadow of her foster sister, Alex (Chyler Leigh), and learned to conceal the phenomenal powers she shares with her famous cousin in order to keep her identity a secret.

Years later at 24, Kara lives in National City assisting media mogul and fierce taskmaster Cat Grant (Calista Flockhart), who just hired the Daily Planet's former photographer, James Olsen (Mehcad Brooks), as her new art director. However, Kara's days of keeping her talents a secret are over when Hank Henshaw (David Harewood), head of a super-secret agency where her sister also works, enlists her to help them protect the citizens of National City from sinister threats. Though Kara will need to find a way to manage her newfound empowerment with her very human relationships, her heart soars as she takes to the skies as Supergirl to fight crime

The supporting cast is rounded out by Jeremy Jordan as Winn Schott, Peter Facinelli as Maxwell Lord and Dean Cain and Helen Slater, whose roles have yet to be confirmed. There was also a rumor that Superwoman may be introduced into the series, but it has yet to be confirmed.What other DC Comics villains do you think should be brought on for Supergirl? Take a look at the trailer and poster below, and chime in with your thoughts.