In DC comics Linda Lee Danvers is whose alter ego

Supergirl
Supergirl is a fictional superheroine appearing in comic books published by DC Comics and related media.

The character was created by writer Otto Binder and designed by artist Al Plastino.

Going by the real name Kara Zor-El, Supergirl is the biological cousin and female counterpart to DC Comic's iconic superhero Superman, created by writer Jerome Siegel and designed by artist Joseph Shuster.

The Supergirl character first appeared in a story published in Action Comics #252 (May 1959) titled "The Supergirl from Krypton".

Since the character's comic book debut, Kara Zor-El's Supergirl has been adapted into various media relating to the Superman franchise, including merchandise, television, and feature film.

However, during the 1980s and the revolution of the Modern Age of Comics, Superman editors believed the character’s history had become too convoluted, and desired to re-establish Superman as "The Last Son of Krypton".

Supergirl was thus killed during the 1985 limited series Crisis on Infinite Earths and retconned out of existence.

In the decades following Crisis, several characters unrelated to Superman used the alias "Supergirl".

Read more...https://en.wikipedia.org/wiki/Supergirl_(Kara_Zor-El)