Project Cadmus will be the main villain in the upcoming season of "Supergirl," and it is bent on removing all forms of extraterrestrial life on earth. This was revealed by "Supergirl" executive producer Andrew Kreisberg, who also revealed that everything will start to unfold as soon as the premiere episode of season 2 starts to air.

"They're fanatics. They're true believers. It's a collection of scientists, of every bright, patriotic people who truly believe what they're saying. That makes them even more dangerous," he said.

Aside from Project Cadmus, another big villain is set to arrive in season 2, but the character will be introduced in the second half of the season.

"Supergirl" has added more cast members for its upcoming season, raising the stakes for the Girl of Steel. The new additions to its cast indicate the desire of The CW to capitalize on the shared universe of its four current shows.

Actress Sharon Leal of "Boston Public" in 2000 is set to portray Miss Martian next season. Previous reports also revealed that Tyler Hoechlin and Chris Wood would join the cast of "Supergirl" season 2 as Superman and Mon-El, respectively.

In other news, the much awaited "Flash"/ "Supergirl" musical crossover is set to air around episode 13. While the details are still few and far between, recent reports suggest that the crossover will feature songs from pop culture catalogue and will walk in the footsteps of the sci-fi musical "Once More with Feeling." Joss Whedon is reportedly going to direct the episode.

"Supergirl" season 2 premieres on October 10 on The CW.