The first trailer for The Super Mario Galaxy Movie is perhaps best described as a loose series of sights, sounds, concepts, and references designed to excite the millions of Super Mario fans who will help this movie earn (roughly) $27 billion when it is released on April 3, 2026. The end of that trailer largely focuses on Rosalina: the cosmic princess who made her debut in 2007’s Super Mario Galaxy and has since become a recurring member of the Super Mario roster.
If you’re not deeply familiar with Super Mario lore (yes, there is Super Mario lore), you likely didn’t make more of Rosalina than what one bare trailer can tell. She’s new, she’s voiced by Brie Larson, she’s got a few tricks up her sleeve, and she really does look remarkably like Princess Peach. Believe it or not, that last, seemingly insignificant takeaway is actually the basis of a rather unusual fan theory. And those who are deeply familiar with Super Mario lore are starting to believe that The Super Mario Galaxy Movie may confirm at least a version of that bizarre theory.
That theory essentially states that Rosalina is Peach’s daughter from another timeline/dimension. Again, wild stuff, but if you let yourself dive down that rabbit hole, you’ll find that it goes a bit deeper than you probably imagined.
Throughout Super Mario Galaxy, players have the chance to learn a little more about Rosalina’s backstory through a series of Storybook segments. A few of those segments focus on Rosalina’s childhood. In them, we learn that she lived with her mother in a castle on a hill. We even see a brief glimpse of her mother: a tall, regal figure with long hair who bears at least a passing resemblance to Princess Peach (and Roslina herself). There are other details in that backstory that seemingly tie Rosalina into the wider Super Mario universe (such as a reference to her father’s mustache in the French version of the game), but those segments for the loose basis of the idea that Princess Peach is Rosalina’s mother.
“But how would that even be possible?” you’ll probably find yourself asking, when you realize that Rosalina and Peach are roughly the same age. Well, The Game Theorists YouTube channel popularized the idea that the Peach/Rosalina lineage can be attributed to a larger fan theory that suggests the Super Mario universe is loosely connected by various timeline shenanigans. The basic idea is that the games take place on different timelines and that those timelines occasionally reset, diverge, merge, and get reshuffled. So, maybe Rosalina somehow escaped a timeline where Peach is her mother and later meets her “mother” when she crosses over into another timeline.
Before you think too much more about that idea, I should probably mention that it is almost certainly not true. The fan theory, much like fan casting, is largely based on how similar Rosalina and Peach look. However, it’s not like Nintendo has shied away from releasing similar-looking characters in the Super Mario universe who have no blood relationship (Mario/Wario, Luigi/Waluigi, etc.). Furthermore, Nintendo generally doesn’t think about the lore of their games nearly as much as fans do. The entire Rosalina backstory was reportedly written by Super Mario Galaxy director Yoshiaki Koizumi in secret, and even Koizumi was surprised it was approved so quickly. Nintendo has made no real effort to logically connect the Super Mario games, and the reshuffling theory the Peach/Rosalina relationship is largely based on is basically a cute fan-led attempt to do just that.
There is a little more to this than the usual “let the kids have fun” fan theorizing, though. Actually, what makes that theory interesting in this instance doesn’t come from fans or even the Super Mario games. It comes from The Super Mario Bros. Movie (no, not that one… the recent one).
There’s a scene in that movie where Mario asks Peach where she is from. Peach doesn’t recall exactly where she comes from, but we do see a flashback in which she arrives at the Mushroom Kingdom as an infant wearing a skirt covered in moons and stars. Peach then accepts the possibility that she may be from one of the many other galaxies in their universe. In case the hint wasn’t strong enough, we even see Peach stare off into the night sky at the stars when the conversation is over.
Put it all together, and it really does feel like The Super Mario Galaxy Movie will establish some kind of familial connection between Peach and Rosalina. While the idea that Rosalina is Peach’s daughter still requires Primer levels of time and universe manipulation to buy into, the idea that Peach is Rosalina’s daughter (or, more likely, her sister) feels relatively easy to buy into within at least the confines of these films.
And while nothing has been confirmed quite yet, the stars are seemingly aligning for Nintendo to give some life to one of the more absurd fan theories out there. Will Nintendo regret indulging the obsessive fan theory community? Have they received any of my letters regarding which of the many Legend of Zelda fan theories they should canonize in the upcoming live-action movie? Only time will tell.
