Supergirl - the comic history of Kara Zor-El

gamesradar.com:

Supergirl is front-and-center in the new trailer for The Flash, which will have its first official screenings at CinemaCon. The film, loosely based on the 2011 comic story Flashpoint, takes place in an alt-timeline created when Barry Allen tries to rescue his parents from death and imprisonment by going back in time - and where Zod, the villain of Man of Steel, reigns over Earth with an iron fist.

To fight Zod, Barry (or Barrys, as there are two versions of him in the film) recruit a Kryptionian of their own to their cause, but not Kal-El. Instead of Superman, they recruit Supergirl (Sasha Calle), reportedly a version of Kal-El's cousin Kara Zor-El.

But The Flash's Supergirl isn't quite like any specific version of the character from comics - and she's even quite different from the version of the character in the comic book Supergirl: Woman of Tomorrow, which will soon be adapted into its own DC Films movie.

With a publishing history dating all the way back to 1959 that encompasses multiple different incarnations of the character and several previous high profile film and TV adaptations, the comic book history of Supergirl is a lot to take in.

Before the debut of the first official Supergirl, there were several versions in Golden Age DC lore, most of whom were gimmick characters who only lasted an issue or two before their stories were done. But positive reception to the concept of the character - a female counterpart to Superman - led to the introduction of Superman's cousin Kara in 1959's Action Comics #252 (the Zor-El surname would be added later).

Created by writer Otto Binder and Al Plastino (who had also previously created Shazam's superheroic sister Mary Marvel for then DC rival Fawcett Comics years prior), Kara