Marie has always been an afterthought. Her parents treat her like a servant, and her flawless older sister, Anastasia, is the family's shining star. Even at Marie's own birthday party, all eyes are on Anastasia--so much so that no one notices when Marie sneaks away.

But in the quiet of the evening, she has a chance encounter with a captivating man with striking green eyes: Count Cyrus. Their brief meeting feels like a dream... until reality comes crashing back. Soon after, a marriage proposal arrives from the count--for Anastasia, of course.

Except... something doesn't add up. The gown that arrives with the proposal? It's clearly made for Marie. Could there be a mistake? Or is this the start of an unexpected love story?

Betrothed to My Sister's Ex has story by Tobirano and art by Mai Murasaki. English translation is done by Rymane Tsouria with an adaptation by Zubonjin. Published by Seven Seas Entertainment (December 11, 2026).

Rebecca Silverman
Rating:

I admit it: I am a sucker for a story about someone making the slow journey from victim to survivor. Betrothed to My Sister's Ex may be frustrating to readers not as invested in the Cinderella subgenre, because Marie Chandelan's path is very often interrupted by her own emotional struggles, making it a “one step forward, two steps back” sort of situation. But that's what it's like a lot of the time, because when you've been beaten down as much as she has, and for so long, even True Love™ can't just swoop in and save the day.

The second daughter of the Chandelan barony, Marie has been relegated to servant status her entire life while her parents favored her older sister Anastasia. (No word in this volume about how they treated her younger brother; he doesn't even get a name.) There's no apparent reason for this, which baffles male lead Kyros; they just seemed to hate her because they're awful people. Comments about her height and red hair are the closest we get to any understanding of a motive for the mistreatment, but that makes sense: Marie is the first-person narrator of the novel, and she's been so beaten down that she no longer looks for a reason for her treatment, if she ever did. It's a survival tactic rather than poor character writing, and by the time we meet her on her eighteenth birthday, she just accepts her parents and life as the way things are.

Even if you've seen the anime adaptation (which aired in the summer 2025 season), Marie's life is viscerally awful. Her casual mentions of “being allowed to bathe” or “being granted soap” are horrifying, as is her father's stricture that she, in his words, prostitute herself to Kyros to make up for her sister Anastasia dying en route to be his bride. Marie is a useful object to her parents, and not even one that they feel needs to be taken care of – she's the old shovel in the back of the barn that serves a purpose. This is something that Kyros suspected from their first meeting, but even then he didn't realize how bad it was because he got the sisters confused – he thought that Anastasia was the mistreated younger sister, falling into that trap because the tall redhead was in tatters in the yard while the short blonde was the center of attention at the birthday party he'd been invited to…Marie's birthday party.

Many of the lighter moments from the anime aren't present here. Marie's first person narration narrows the focus to her perception, although Kyros gets two shorter chapters and Toppo a short story. It can be dark, but there's still clear progress for Marie as she becomes more accustomed to the idea that she's allowed to be happy and taken care of, even as her parents' communications risk upsetting the entire situation. I don't love the use of words like “cute” and “cool” in the translation, as the rest of the vocabulary isn't nearly as modern, but this is still a good book, and if you enjoyed the anime, I'd definitely recommend it.