James Gunn has changed comic book lore surrounding Superman and Supergirl's familial relationship – potentially in order to make sense of the film's most devastating revelation.
Warning: Spoilers for Superman below!
"You’re assuming that everybody on Krypton is the same! And how would she know?" Gunn told Rolling Stone., when asked why Supergirl never told Superman that his parents sent him to Earth for nefarious reasons. "She’s younger than him, so she wouldn’t know. She wouldn’t know anything about his parents."
In Superman, Kal-El learns that his parents Jor-El and Lara Lor-Van sent him down to Earth, not to protect and serve its citizens, but to rule over and enslave them. This is different from Superman's comic book origin, as it doesn't include the whole rule over and enslave them part. Because of this particular change to the origin story, it would only make sense to alter Kara Zor-El's relationship with Superman – and it isn't necessarily that Kara Zor-El aka Supergirl is younger than her cousin Kal-El.
In the comics, Supergirl was a teenager when Krypton exploded – which happened when Superman was just a baby. She was sent down to earth to take care of the infant Kal-El but her ship went off course, causing her to be stuck in suspended animation. By the time Kara woke from her deep sleep, Superman was already an adult, and she was still 16 years of age.
In the comics, Kara knew all about Krypton as well as knowing Superman's parents. If this were the case in the movie, this means Kara would know all about Jor-El and Lara's true motives for sending him to Earth. Gunn's above statement implies that Kara was potentially born after Superman, which would mean she never had the chance to meet his parents and therefore wouldn't know about Krypton's history, and has something of a different origin story. I suppose we'll have to wait until 2026 to find out.
Superman is in theaters now. Supergirl hits theaters on June 26, 2026. For more, check out our guides to all the upcoming DC movies and TV shows and how to watch the DC movies in order.
