The Flash reveals a lot of things that are setting up the beginning of rebooting the DCU. One of those things happens to be unveiling Supergirl, her powers, motives, origin, and how she is related to Superman.
Well, far beyond The Flash movie, you might wonder if they are canonically related in the DCU and in the comics. Luckily, you can read all about it here!
Are Superman and Supergirl Related in the DCU?
In DC’s The Flash, when the two Barry’s and Michael Keaton’s Batman were looking for Henry Cavill’s Kal-El, they instead found Kara Zor-El / Supergirl (portrayed by Sasha Calle).
While she wasn’t the Superman they intended to save, the present Barry still made her come with them, which saved the group from getting obliterated by the Russian guards in charge of imprisoning Supergirl in their headquarters.
This turned out to be in their favor because Supergirl managed to get Barry his powers back.
In the film, Supergirl was wary of the group, asking them why they were looking for Kal-El in the first place, and when she rendered them trustworthy, she admitted her true identity: Kara Zor-El / Supergirl.
Kara also revealed that she was sent to protect Superman since they are Kryptonian cousins.
Unfortunately, in the reality of the young Barry (the time present Barry was stuck in), General Zod revealed they had already killed Kal-El before Kara could save him.
ALSO READ: How Does The Flash Time Travel?
Is Superman Canonically Related To Supergirl?
In the DC comics, Superman has always been canonically related to Supergirl. Their fathers, Zor-El (Supergirl’s father, the older sibling) and Jor-El (Superman’s father, the younger one) are brothers, after all.
Despite their differences, when they found out their home planet Krypton was on the verge of doomsday, they had their children, Kara and Kal-El devise a plan to get deployed to a different planet. In this case, on Earth.
Kara was sent to protect her cousin, Kal-El, however, since Kal-El was the first to arrive on earth, he and Kara got separated, which flipped the plan their fathers conjured.
In this case, Kal-El landed in Kansas as an infant and got adopted by the Kents, meanwhile, with Kara being sent off in a ship while in slumber, she was not aware that her rocket had been circling the sun for decades on end.
30 years had already passed when she finally landed on earth to set off and find Kal-El, not realizing she remained the same age when she left Krypton as a child.
Her body had only begun changing when she saw and was exposed to the sun after those decades, telling her she was no longer on Krypton anymore.
READ MORE: How Did Barry Lose His Powers in The Flash?
Does DC Have Plans For A Supergirl Movie?
Well, in January 2023, James Gunn announced Supergirl: Woman of Tomorrow would be a part of the new DC slate.
Though it remains to be seen whether the Supergirl movie would still be played by The Flash’s Sasha Calle, the movie was promised to be a different take on Supergirl, in which we will be seeing how Kara was raised on Krypton and the horrifying events she grew up with before she ended up on Earth.
As of writing, Supergirl: Woman of Tomorrow has no release date yet or any confirmed plot synopsis, or if we would see Supergirl interact with her cousin, Superman.
But it does seem to be based on Tom King’s comic book with the same name. The official synopsis of the comic book reads (via Goodreads):
Kara Zor-El has seen some epic adventures over the years, but she now finds her life without meaning or purpose. Here she is, a young woman who saw her planet destroyed and was sent to Earth to protect a baby cousin who ended up not needing her. What was it all for? Wherever she goes, people only see her through the lens of Superman’s fame.
Just when Supergirl thinks she’s had enough, everything changes. An alien girl seeks her out for a vicious mission. Her world has been destroyed, and the bad guys responsible are still out there. She wants revenge and if Supergirl doesn’t help her, she’ll do it herself, whatever the cost. Now a Kryptionian, a dog, and an angry, heartbroken child head out into space on a journey that will shake them to their very core.