Mizuto and Yume’s parents get remarried to each other, making them step siblings. Thing is, they dated each other in middle school. Instead of telling their parents, they decide to pretend not to know each other, and maybe even like each other, in front of their parents. But in reality, they can barely stand each other and squabble all the time. Trapped in the same house they have no choice but to work out their differences…while trying to establish dominance over each other and decide once and for all who the “big” sibling is. Big Sister or Big Brother. Lol

The volume gives you some backstory and the read slowly realizes that maybe their differences are because of miscommunication and some personal growth, at least on Yume’s side. Mizuto’s jealous streak shows throughout the flashbacks. It doesn’t help that the boys in their class are openly using him to try and get closer to Yume… The bitterness and snarkiness between them, in private, seems pretty on par for teenagers when forced into proximity to their ex.

For a first volume, this was pretty good. The reader gets enough backstory by the end that you get a bit of an idea how this is going to go…maybe. I have theories! I enjoyed the art and may a just say, any close up of people’s faces had some exquisite work done to make the eyes ‘come alive’ on the page.

Okay the premise in this was interesting but it icked me out so much so many times!!! I was like You're done.

ARC gifted by NetGalley for review

This was fun! It is a very unserious high school romance manga. Don’t worry, it’s not incest, they dated and broke up before their parents even introduced themselves. It was cute watching everyone get awkward and blushy

I was not a fan of this manga and will not be reading any more issues of it. Thank you for the early copy!

This wasn’t as funny as I’d hoped. I wasn’t sure whether the story would lean into comedy or take a more serious tone, but honestly, it mostly just made me uncomfortable.

Mizuto and Yume dated in middle school but eventually broke up after drifting apart. Not long after, their parents announce they're getting married—making the former couple step-siblings. The premise alone was already a little awkward, and the early chapters didn’t do much to ease that feeling.

Once school starts and more characters are introduced, the pacing picks up a bit, but not enough to keep me interested in continuing the series. The story didn’t quite land for me, and I didn’t feel a strong connection to the characters or the humor.

Thank you to NetGalley for the free copy—this review reflects my honest opinion.

I thought this would be a cute and funny read, but it kind of missed the mark on that. It was hard to get a read on the ages of the characters and some of the content made me uncomfortable.

This book is as confusing and annoying as the title is. In this manga, you have two kids who dated in middle school and broke up two weeks ago because their parents got married. They dated for over a year. Even if it was a middle school relationship, don’t you think the parents would know something. Even not taking that into account, the arguments and the historical connotation of their middle school relationship is as obnoxious as a middle school relationship usually is. The male character talks to the librarian so the female character think he’s cheating. This is so ridiculous. I wish it was better and it’s a DNF at 30%.

This one was so freaking cute and well drawn!
It was simple and not too much happened in this first volume, but I loved it! 😍🫠

Thanks NetGalley and the author for this ARC in exchange for an honest review!

I recently started reading mangas, and the story and title instantly caught my attention. I was pleasantly surprised by how adorable the story was, and I loved the palpable tension between the two main characters. The artwork is absolutely stunning, and it really added to the experience. I enjoyed it so much and can't wait to continue reading this series!

Another Manga that I requested because the teenager was interested. The teenager found it interesting, cute and full of humour. I concur with the teenager, it's an interesting story and I/we would read further instalments of the series.

I had so much fun reading this!
The art is amazing!
I can't wait to know how this two will get along in Volume 2!

I dislike when young characters are sexualized so this is absolutely not for me at all.. I expected it to just be a silly manga but yeah no it’s quite awkward and weird. DNF

This was a different take on the step siblings story. but the story was interesting. The art was beautiful and I enjoyed the differences in the characters based on the part of the timeline the book was in both in visual and personality. The only problem I had was how slowly the book moved, which is not a deal breaker by any means and it works as the first book so that the story can get set up and the characters established. The story itself was cute and I enjoyed the competitiveness between them.

My Stepmom's Daughter is My Ex Vol. 1 is a fun but somewhat mixed read. The premise is undeniably entertaining—exes turned stepsiblings forced to navigate their new family dynamic while keeping up appearances. The awkward tension and rivalry between Mizuto and Yume create plenty of amusing moments, and the classic rom-com antics make for a light, easy read.

I enjoy the genre, and this manga delivers on the blend of romance, comedy, and slice-of-life elements. However, I wish it leaned more into the comedic side rather than balancing romance and drama so evenly. Some of the interactions feel a bit repetitive, and the story doesn't fully commit to being either a heartfelt romance or an over-the-top comedy, leaving it feeling somewhat in-between.

That said, I'm excited to see how the anime adaptation captures the story! I have a feeling it will enhance the humor and energy, which could elevate the experience beyond what the manga provides. Fans of lighthearted rom-coms will likely enjoy this, but if you're looking for a more comedy-driven take, this volume might not quite hit the mark.

Imagine living under the same roof as your ex unexpectedly. Mizuto and Yume were dating 2 weeks prior when their parents suddenly announced they are getting married and living under the same roof. This first volume shows that Mizuto and Yume defiantly still have feelings for each other, but are trying to navigate their new living situation while trying to make the other fall for them. This first volume made me laugh and the awkwardness of everything was so wonderful! I can't wait to see what dirty tricks they have up their sleeve next volume and what new situations they get themselves into! I'm very grateful for the opportunity to ARC read this and cannot wait for volume 2!!

Cute art, interesting story. It was the right combination of awkward and interesting. You could feel for the characters and their struggles with being an ex couple who still have some feelings of longing while also being new step siblings.

Despite the odd title this one was pretty cute.

Have the main couple who were dating BEFORE their father and mother met. During dating everything was going smooth till they broke up. A year later, their parents met, and married, and now they live together as brother and sister. Weird right? But it can happen, it's not that far fetched. The problem is these two have feelings for each other they don't wanna address.

Leading to a lot of funny moments, mixed with sexual tension, while learning how to live together. All in all, light hearted and fun, and something I enjoyed reading when I didn't think it be nearly as good as it is. A 4 out of 5.

It's a good story, however I don't do sibling stuff. So what happens here is thw main characters were together in middle school but no one knew and then they subsequently broke up.

Fast forward about a year or so and their parents are together making them step siblings. Being exs there's still some tension between them, including sexual tension so this made me a bit uncomfortable but this seems to be a going trope in the anime community. So if that's your vibe, go for it but for Me, I won't be continuing this series.

Thank you to Udon Entertainment and Netgalley for the opportunity to read and review this manga. Honestly, I think that I am just over this trope. This is because the angst that is involved with it and some of the trickery that I just cannot stand anymore. However, I think if that is something you are interested in trying a manga with this tropes for the first time, this one would be fine to try. Because of these points, I have to give this manga a 3 out of 5 stars.

e-ARC from NetGalley.

The synopsis is the title of the book.

I enjoyed the art style and the concept, but the sexualization of minors and the whole sibling fetish thing turned me off. It's okay to like your step sibling. It's not okay to pretend they're your bio sibling & tell people you're in love with them.