My Stepsister is My Ex


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A certain boy and girl in middle school became a couple, flirted with each other, disagreed on trivial things, became more frequently irritated with each other… and eventually broke up upon graduation.

Now in highschool, the two of them, Irido Mizuto and Ayai Yume, wound up meeting each other in the most unexpected fashion.

The former couple, brought together through parental remarriage, decided to be mindful of their parents’ feelings and came up with a ‘sibling rule’—where the the first one to become conscious of the other as a member of the other s*x loses, but…

When they encounter each other in the bathroom, commute to and from school together, along with the memories of the past and living under the same roof, just how do they disregard each other!?

Associated Names
One entry per line
Mamahaha no Tsurego ga Motokano datta
My Stepmom's Daughter Is My Ex
My Stepsister is My Ex-Girlfriend
Related Series
Gimai Seikatsu (5)
Otonari no Tenshi-sama ni Itsu no Ma ni ka Dame Ningen ni Sareteita Ken (LN) (1)
Motokano to no Jirettai Gisou Kekkon (1)
I Kissed My Girlfriend’s Little Sister (1)
Kurasu no Daikiraina Joshi to Kekkon Suru Koto ni Natta (1)
Recommendation Lists
  1. romcom
  2. Sugar daddy? Sugar mommy? Say sike, its sugar stor...
  3. this list is about Siscon and Brocon (Incest)
  4. Reading
  5. Read Later When There Are More Chapters

Latest Release

Date Group Release
08/08/21 Hellping v7 afterword
08/08/21 Hellping v7c5
08/08/21 Hellping v7c4
08/04/21 Hellping v7c3
08/02/21 Hellping v7c2
08/01/21 Hellping v7c1
06/21/21 Hellping v6 afterword
06/21/21 Hellping v6c6
06/21/21 Hellping v6c5
06/10/21 Hellping v6c4
06/08/21 Hellping v6c3
06/06/21 Hellping v6c2
05/20/21 Hellping v6c1
05/15/21 Hellping v5 drama cd
05/15/21 Hellping v5 afterword
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19 Reviews sorted by

Hell_ping rated it
August 11, 2021
Status: v7 afterword
Perhaps it would be boring if readers are only looking for romantic progression and ignore every single character development in the story, like some others would have insinuated anywhere and not justify so?

Do we also ignore how the main five evolve as people, instead of just reading the story for the sake of the faux-domekano plotline and hoping for a resolution without looking into the whats and the whys as to why the characters are as they are, and instead only nitpick because the romance isn't progressing as fast as... more>> they would like?

Do we also ignore how the main five look into their past and actually reflect on their actions, something that is blatantly missing in most other light novels out there, and also come to a positive conclusion on what they should improve on, even if the effort is for naught, and instead only nitpick because the romance isn't progressing as fast as they would like? Do we also only look at the superficial of the actions and complain that there isn't any progression because the only thing people look at nowadays is simply romance = progression?

Because 'My stepsister is my ex' isn't this kind of story.

Alright, admittedly, as noted by the author in the afterwords, this series was initially meant to be a love-hate relationship because the stepsiblings who were once a couple had to get used to living together. There are some romcom hijinxs here and there, but as you read further, you'll see more depth into each other's character, sometimes boring, sometimes scary, sometimes hilarious, but that's part and parcel of being human (aside from all the contrived coincidences involving four out of the five characters)

We have extroverts like Kogure, introverts trying to be extrovert (changing oneself) like Yume, introverts who'd rather remain the same like Mizuto. Not everything is about romance in this story, for they need to understand each other to get along better as ex-couples, and also as friends/siblings.

Bottom line, if you're just looking for a romantic resolution in this story, this story isn't for you because it looks into way more things than that, and most readers can't have that. This isn't like Otonari no Tenshi-sama when it gets sweet and then nothing else later on in the story. If you just want romance resolution, just read the author's other series 'Do you think you can run after reincarnating, nii-san?' <<less
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tornberry rated it
August 13, 2020
Status: v1c8
Very good. Sweet and fluffy story, it is basically a story where two middle school teenagers broke up because they didn't understand their partner and were sulking towards each others.

As they've been saying on their monologue, from that point onwards they could have gone separately without getting back or even communicate anymore, but because of plot they ended up as step-sibling and classmate on their new high school. This story is about their everyday lives, getting to understand the other personality much better than back then when they were still... more>> a couple, without any fake mask/personalities.

It is so obvious that both of them still hold each other as a very important partner, unconciously not letting the other to feel hurt; But since they are your typical teenagers, they are so stubborn with their own beliefs.. Trying so hard to convince themselves that they hate each other instead. I have a high expectation on this series. <<less
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AJ1703 rated it
December 12, 2020
Status: v7 afterword
Thank heavens the MC has a functioning brain. In which, honestly is rare these days. The story is good and I love the character interactions.

First of all, the characters are all well-written out. Even if they're all relatively new ones, they all have their unique personalities. The author introduced them to us properly, giving more information about them. More or less, they were all going to play a role in the main couple since the MC and FMC's environment would be influenced by them as to how the main characters... more>> would act.

The story, it's rather slow but justified. Every volume is like a month that had passed, giving insights and important events as highlights of that month. For example, exams, summer, school festivals, and more. Each of those events would be where the story of each volume would revolve and would play a major role on it. Although one may think that some of the ideas are just re-used, what's not noticed much is the subtle difference in how our main characters would act and how they would think. The thing is, like what translator-san, aka Hell_ping stated, the main focus of the story is how our characters would improve as a person. We all learned that from volume 1 they truly hated one another (apparently they did cuz the author said so, but for me, it was a different case but oh well). As time goes on, the main characters would learn everything about the other in their day-to-day lives. So in a way, it's more of a slice-of-life series at this point but like already said before, well-written. The author leaves little foreshadowings every volume that becomes relevant for future volumes. That's how it always went. So if you weren't paying attention properly or reading briskly, you wouldn't notice them at all. That's what others fail to notice. One of the characters get unnecessary hate, wherein she was the one who actually did the most for the main characters is quite saddening. I'm talking about

Isana Higashira


Overall, an enjoyable series to read, and would highly recommend others to read so. I've had 10 people read this series and I only received positive feedbacks from them. It goes without saying for me, that it's truly worth 5*. <<less
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Rampage Debut
Rampage Debut rated it
July 18, 2021
Status: v6 epilogue
This novel took me by surprise and in an extremely good way.

The main characters of this story are Mizuto Irido and Yume Ayai who became step siblings after their parents' remarriage. However, unlike normal siblings they harbor a secret, they were actually a couple almost an year before and only one month after their breakup, they find themselves tied in a relationship as siblings with their parents being unaware of their past relationship. How will this ex-couple respond to their new relationship?

Volume 1 is basically all fluffy romance (?) with... more>> each chapter switching to one of the step siblings' PoV, a feature that continues in all volumes. The first Volume is basically an introduction and it does its job well of conveying the past and present relationship of Mizuto and Yume.

However, it is the subsequent Volumes that really enrich the reading experience. From Volume 2, the story goes into indepth details of their past relationship, their thoughts, their views and what events led to their subsequent breakup. They learn more about each other as family, learn sides of each other which they had never seen before when they were dating and the misunderstandings and misconceptions they had about each other which led to their falling out. As they mature, their new experiences only reminds of how lightly they had taken their earlier relationship with a non-commital attitude.

And finally starting from Volume 4 onwards, they once again start to get close to each other with newer resolve to start their couple's relationship even better than before, now having known all they want to know about each other as family. It is precisely because they became step siblings that they can form even stronger bonds as couple. Volume 4 which is centered on Yume and Volume 6 which is centered on Mizuto's thoughts are my favorite volumes of this series so far. I never expected to having come across so much detail over their thoughts and course of actions in a story about step siblings. Simply amazing. <<less
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KhayDesu rated it
April 18, 2021
Status: v4c1
Pretty fun


Although i've read many series like this its always fun and fresh to read a new one and maintaning that sense of excitement is pretty good and I feel this way with this novel. The two mc's Yume and Mizuto are pretty much hardcore tsunderes they go the roundabout way of showing affection towards each other. Though its pretty obvious that they'll unite its still pretty fun reading it and also the side character are pretty interesting as well. Pretty good if you ask me I'm still looking forward... more>> to it <<less
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johnmc rated it
August 19, 2021
Status: v7 afterword
First and foremost, this is a fun read. There are decent character developments. The interactions are good and conversations feel natural. But just as the other review points out, it gets repetitive fast. To be honest, repetition itself is not bad but it makes me confused about what the author actually wants to convey here. This series started out very good and has an intriguing setting. But after that, the series returns to a typical slice-of-life LN where it focuses on the daily interactions of MC and FMC with others... more>> (rather than between themselves).

Personally, I find the series' focus on other couples/love interests annoying. Not that they are bad, but I am here to find out how the MC and FMC will grow their relationship. I want to see more of their mutual interactions without the heavy dependence on side characters. According to my humble estimation, 70 to 80% of each volume, after vol 4, start to deliberately explain the side love interests while an audience like me is rewarded with a short, swift, and sweet moment of MC-FMC at the very end of the volume and that's it.

At volume 7, I am completely lost as I cannot catch up with the introduction of so many characters, each with their own personalities and stories. Each of them conveys different messages and/or influences toward the FMC. In the end, it becomes a mess. Maybe I'm a bad reader and that's on me, but when so much focuses are dedicated to these side characters, you will also start to question the direction the author wants to take. <<less
6 Likes · Like Permalink | Report
Kalor rated it
September 29, 2021
Status: --
First volume was very good, but like others stated, story gets a little boring when author focuses on the other couple with strange personal traits. I just couldn't force myself to be interested in them. And they were obstructing story constantly.

If it comes to main couple, FMC cannot decide what she wants and when she makes a little progress in one direction she immediately retracts two steps back, over and over. MC on the other side doesn't seem to be even interested in romance.

My main complain however are illustrations, they... more>> are high quality but age-wise I would place them in early middle school rather than high school, which is quite disturbing when comparing to their adult-like actions. <<less
5 Likes · Like Permalink | Report
esr95tkd rated it
April 9, 2021
Status: v4c1
This Kaguya-sama Love is a war meets stepsibling p*rn.

I hate myself for getting invested in this. The premise is so dumb, the title as well but then the damn characters are so well written you wouldn't expect it.

Two tsunderes trying to convince themselves they hate the other one. Three chapters in and you can read between the lines of what they actually love from each other. You never get to see their actual thoughts when they are being nice or concerned about the other.

So I leave with the piece of... more>> trivia that comes in ch 2 but it's basically the end of this series (even if its still a bit away)

Stepsiblings can get married to each other <<less
5 Likes · Like Permalink | Report
June 5, 2020
Status: v1c2
Stepsibling romance. I'm aware stepsiblings are used so that it's "technically okay", but family is family.

Putting that aside, it's pretty typical for a romance novel.

They still love each other, they can't stop their feelings. By the second chapter, they already were about to kiss until their parents interrupted by coming home.

They fight, they blush, they insult each other while trying and failing to hide their feelings.
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Timewinders rated it
September 25, 2021
Status: v4 afterword
This story has good writing, interesting character interactions, and character development. The main couple is likable and cute. However, the pace is very slow. The first two volumes were great, but the story moves away from its focus on the main couple. Time is wasted on more and more side characters and the romance between the main couple progresses extremely slowly. It's a shame because I really do like the main couple and I want them to be happy, but I'm not going to wait another two years for them... more>> to finally admit their feelings to each other. I think this is the kind of series that you only want to read once it is already complete. Check this out again in a few years once the series is finished, I for one am going to do just that. <<less
3 Likes · Like Permalink | Report
Firehearty rated it
August 10, 2021
Status: v7 afterwards
Gets repetitive after the female MC realises she likes the MC (who are step-siblings) :

    • Female lead: I must seduce MC and make him only think about me.
    • Then she asks her friends some dumb plans to seduce MC (like walking naked after bath).
    • Her plans fail because MC has poker face after seeing her naked.
    • Then Female lead complains her friend how their dumb plan failed.
    • MC spends 90% of time with another girl who is his best friend, they get along so well that they'd make perfect couple.
    • MC and his girl best friend having 10x times more plot development than main couple, but We all know she's just a plot device, MC is gonna still fall for his step-sister at the end anyway.
    • Then some school stuff happens, MC and his girl best friend spend more and more time together (90% of the time).
    • Female MC gets jealous, asks her friend for another dumb plan to seduce MC. Which fails.
    • At the last chapter of each volume - Female MC becomes damsel in distress (MENTAL SITUATION), MC and Female lead have some intimate conversation,
    • Now you you expect them to progress with their relationship but nope, In the next volume the female lead again comes up another dumb plan to seduce him.
3 Likes · Like Permalink | Report
AkatoshJ rated it
March 19, 2021
Status: v3 afterword
This is a beautiful work. Not only interesting and funny, but well written, and makes you think too. The past is double linked to the present, and makes you understand and see everything under a new light.
3 Likes · Like Permalink | Report
lumlum rated it
January 11, 2021
Status: v1c3
Very High Quality, both parties have a good mind and go through memory lane resolving past misunderstandings and learning to love each other again!
3 Likes · Like Permalink | Report
yanaro rated it
June 22, 2021
Status: v6 afterword
Surprisingly good story, much different from any other I've read. There was a lot of detours with a love triangel (not exactly) with a character I don't exactly like so it felt really long reading those part. But they're getting there, I suppose.

This is a very good read, highly recommended.
2 Likes · Like Permalink | Report
KPBaron rated it
June 14, 2021
Status: v5c7
This novel is absolutely one of the best novels I have ever read. The quality, plot, character development, their thought process, etc are high quality. This novel really takes me on a roller coaster of emotion and I absolutely love the relationship development of the MCs in volume 4.
2 Likes · Like Permalink | Report
July 25, 2021
Status: v1c7
story is pretty good so far but that minami girl really freaks me out. Just drop dead already I don't want yume to have this crazy psycho stalker bothering her anymore. Even I would call cops over what she did in v1c6 she is plain creepy.
1 Likes · Like Permalink | Report
Temporary ID
Temporary ID rated it
June 27, 2021
Status: v4c7
I'd say this was well done except for the creepy side character minami. Girl's very creepy. I'd rather take her out of the equation. Urrrggh
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siscon rated it
August 6, 2021
Status: v6 afterword
It's really good, got baited with the premise but the story kept me reading this. Still, I'll probably read the rest when the series is finished. It's not really good for my heart, man.
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SeventhTale rated it
June 24, 2021
Status: v6 afterword
I thought this will be a fluffy romance about the ex-couple who is now stepsiblings. Though I expect that there would be serious moments, I didn't expect it to have so many.

The two broke up because they started to hate or notice each other's flaws. I see that as them running away, as they said that when they broke up all the burdens in their shoulders was suddenly gone. This is story about how will they accept everything about each other, that their idea of each other is different, and... more>> how they will become close with each other much better than the past. Their new environment and their friends helps them to make it happen.

Now as you can see, it's not really just a simple fluffy romance story, as it will touch about the mental state of each characters, and their relationship with each other. Volume 1 is the most fluffy and I like since at that point, they are still on each others throat in their new environment as a stepsiblings. The next volumes will slowly show them what they don't know about each other and what are the changes.

It's good story that I will recommend to everyone whether they like a serious romance or just a light hearted one. The side characters have their own spotlights which is I like too. I just rate it as solid 4 because this is not what I expected to read. <<less
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