We're guessing this isn't something that's kept many of you up at night (and here comes a moderate spoiler from The Super Mario Galaxy Movie, so read on at your own risk if you're someone who cares deeply about the story), but Rosalina was introduced in Mario's latest big-screen adventure.
She had a more significant role in the story than many might have thought, as it turned out she is Peach's missing sister. This was a solution that Shigeru Miyamoto himself was involved in, and he seems very pleased with the setup, judging by an interview with Japanese NDW (after translation):
"Since we don't know what kind of game we'll make next with our characters, having too many character backstories would be a limitation. I don't mind being bound by the game's structure, but I don't want to be bound by having created a story, which is why we haven't wanted to make movies for years."
And now it seems that Rosalina's role in the games will also change going forward. From now on, she is simply Peach's sister, both on the big screen and in the digital adventures:
"So, before I made this movie, I hadn't decided on the character's background, but now that I'm making the movie, it's been fun to develop the character in different ways. That's why I want to stick as closely as possible to the settings created in the movie in future games."
Many fans find it a bit strange that these two characters have suddenly been given a sibling relationship, while others really like the setup. What do you think about the new sisterhood setup?