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Onimai: I'm Now Your Sister!

Onimai: I'm Now Your Sister!

Introduction

Self-professed "home security guard" Mahiro Oyama has not left his home in years, secluding himself in his room playing erotic visual novels. This depraved lifestyle causes his prodigious sister, Mihari, to worry about his well-being. In hopes of solving this problem, she devises a plan to rehabilitate him back to normalcy. The first part of Mihari's plan is to concoct a medicine that changes her brother's biological constitution into a bona fide female, much to Mahiro's vehement dismay. Stuck in this predicament, Mahiro has no choice but to live out his life as a cute girl until the effect wears off—if it ever does. [Written by MAL Rewrite]

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Audience ratings

MyAnimeList / Tenrai : 7.64/10 · 94391

1/101081
2/10758
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4/102092
5/104176
6/109707
7/1023410
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10/1011892

Audience reviews

20 · Sample from the first available page, separate from the total number of ratings.

TheFunZ

It's kind of embarrassing to say that this, but this is one of my top anime ever, maybe my mushoku tensei's glaze was overloading at the time when this first came out and I was already accepting this anime with open arms, the premise of the anime are also pretty new to me which also caught my attention. After rewatching this anime again, I can finally somewhat formulate basic reviews of what I think about this anime. The animation is goated, Ryo Imamura's designs are so goated, including in his other works. The opening and ending songs for this anime are so catchy and sweet to listen to, it makes it hard to skip both the ending and the intro. The voice actor that voiced Mahiro Oyama are so goated, she made Mahiro sounds like NEET and a guy that doesn't know what to do except doing the mo…

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FaethyvveIcye

Way more progressive regarding gender-identity and other LGBTQIA+ themes than I expected from an anime with this subject matter. Overall quite light-hearted and not too serious but has a few moments of genuine drama. Watched with a couple of transfemme friends and got a good amount of giggles and in-jokes, both by myself and explained to me. Is a little more on the fan-service side than I'd prefer but not overly so. Should be a part of the 'yuri' tag in the way most of us lesbians also view Madoka and LycoReco as such. If you're comfortable in your gender identity as cis and otherwise outside of the alphabet soup you probably won't like this anime, but if you're "sure you're cis" you'll probably love this.

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sFrontof

I was surprised that an anime like this turned out to be of such high quality. Also, the opening is really good, and the ending was good too. Season 2 has been confirmed; let's see if they can keep going without ruining the quality. I should also point out that if you look at the anime from a broader perspective it's not an innocent show at all. I hope you just watch this anime for entertainment purposes and don't project such takeaways onto yourself (like wanting to be a girl, being trans, etc.). They won't let me post this comment how ridiculous. (Because I didn't meet the word count requirement.) You don't have to read this; I'm just spouting some nonsense. Let me add this, too: honestly, Studio Bind went way too hard on the animation. Why is the character movement so incredibly f…

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MosuSama

Not that I had much faith in the MAL fanbase to rate anime accuratly, whereby most action eyecandy gets overglazed to triple XL status, and leaves everything else to further grow the ever consuming black hole of "7/10", the consensus for Onimai feels unfair still, and it should be rated higher. I came across two recently announced figurines for Onimai, and thinking they were just so cute I might have to buy them, I decided to watch the anime like a good little non-larper that I am. And wow was it good. It really feels like I stumbled upon some CGDCT gold, whereby every facet is firing at all cilinders. The animation is stellar. Not surprised when I halfway found out it's the work of studio Bind. The facial animations can make simple interactions like stealing a bite out of a crêpe look fu…

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arpa_h

onimai was inevitably going to be a hit for me: the premise of a guy waking up as a cute middle school girl is massively appealing to me specifically. what i didn't expect was for this show to be so aggressively life-affirming. there's something worth celebrating in every small moment, and it's never too late to start caring for yourself. go out into the world, make new friends, learn a new skill, start cooking for yourself, and take things one step at a time. what are you waiting for? there's only one person who can take that first step and it's you. every episode is a massive serotonin shot to the veins. feels like it could one-shot a victorian child. inspired me to better my life in a way that no other show, movie, novel, or game ever has before. one of the most important things i've e…

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PlasticDolli

I loved Onimai! I just wish I could share it with other people without looking like a peedo, especially considering that in the manga (which admittedly I've yet to start reading at the time of writing this) the sexualization of the characters doesn't seem nearly as bad as it is in the show. ;-; It has been a bit since I've actually watched the series, I was binging it as it was coming out LOL. But I remember how happy it made me, It was a really fun watch. Besides my initial problem with how the younger characters of the show are depicted, I would totally recommend it if you're looking for a different kind of "Slice of Life" anime! -u-

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MoiraCarey

Whenever an anime treats "small-chest insecurity" as a recurring gag, it’s usually a dead giveaway: these female characters were written by men, for men, projecting their own anxieties about penis size onto the opposite sex. The female body remains under male observation and control. The question is: does Onimai reflect on this by putting a man into the body of a cute girl, or is the premise just a cover story to indulge in the same tropes as everyone else? The gender-bender setup theoretically flips the script on the ultra-polished, moe-overloaded anime format. Mahiro, a NEET and the embodiment of the "dameningen" (the modern Japanese archetype of the "useless human"), likely a consumer of moe himself, becomes the protagonist of a Cute Girls Doing Cute Things (CGDCT) show. Within this sl…

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nordita

Onimai is best described as cute girls doing cute things, delivered with a cozy tone and strong production values. At its core, the show highlights the warmth of everyday friendships while exploring a light theme of personal growth. The premise is intentionally absurd: the protagonist is drugged by his sister and turned into a girl as part of a science experiment. The show never asks the viewer to take this setup seriously. Instead, it functions as a device that allows a slovenly NEET to gradually grow into a more self-caring and sociable person. What begins as a “secret male infiltrator” scenario slowly shifts into the protagonist becoming a genuine member of a group of friends. The story itself is simple and episodic. There are no major arcs or dramatic twists, and the series deliberat…

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Necris

In the beginning I was worried if sex change motive will be annoying or boring for me - so after watching through the entire season - his sex change is only a hook and it lost it's importance after first few episodes. Mahiro is bona fide 100% girl in both looks and character that has zero behaviours that would even indicate her history as a male. At first I tried to explain how skittish she was by her being a NEET, but the longer the season went, the more obvious it became, that it is not the case. So if we ignore sex change, what did we got in the end? A pretty good CGDCT anime in which one of the characters is new to the "Girl Things". If we look at it in this category, then I really can't complain about anything. It has all that makes anime in this genre successful: - Beautiful and pl…

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trashrat3000

Lots of cute and funny moments highlighting the absurdity of the situation that most people have some kind of experience they can relate to in some way or another because everybody's experience in gender is different. Super well done, and i would recommend it to anyone, though i feel like i had to have a strong background in anime to not be made totally uncomfortable. because it's very anime-y. Demographic notes: CGDGT enjoyers - you'll fw this ppl who don't watch a lot of anime - includes a lot of fanservice of children, and can be seen as a little mean or harsh just because of cultural gender rigidity. NEETs - this is the anime for all of those weird fucking figures you collect! must watch! I'm not your mom. I won't tell you that Mahiro is or isn't trans. But his experience is innatel…

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glenalen

Going in, I didn’t have high expectations—mainly because of the low ratings and mixed reviews—but I gave it a shot since I had nothing else to watch. And honestly? It turned out to be way better than I expected. The animation is smooth and relaxed, with soft, beautiful colors that perfectly match the laid-back tone of the show. The music adds a cozy, chill vibe, and the characters are genuinely cute and fun to watch. It gave me Strawberry Marshmallow vibes, just with a bit of modern flair—and yes, there’s some fanservice, which feels kind of unnecessary, but it doesn’t completely take away from the overall charm. Don’t let the negative reviews fool you—if you’re in the mood for something light, colorful, and comfy, this one might surprise you like it did me.

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useless-cheese

This Series does not adapt all the chapters and it adapts them in an odd order. This anime is fun and good but like horimiya just read the manga and get a fuller picture. if you see this review after wards you only missed chapter 4(very trans), 19, and 23, along with most bonus chapters/pages The anime itself is still good, with a bubbly art style that makes our cast look good. the humor in this is good for an anime but what makes this series any fun is watching the characters interact. The main cast are all so charming and distinct.

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Brottoy_II

Onimai is the sort of anime I’m legally not allowed to admit I watched without risking it being a criminal confession. But despite all, it was rather a wholesome little experience. Onii-chan wa Oshimai, or Onimai as it’s affectionately called, attempts to explore a fundamental question every anime fan has pondered since the beginning of time: what if an unemployed shut-in university age otaku/weeb dude suddenly turned into an adorable middle school age girl? I really loved the way this show introduced its premise to the audience. In an average boring anime with this setting, you’d be given a five minute exposition dump about how the mc is an irredeemable NEET with zero social skills and heavily into otaku media, showing him play some generic looking rpg or watch an absolute dogshit in-wo…

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lycoping

This anime has a very simple premise: A hikikomori (shut-in) young man get turned into a middle school girl, and he has to come to terms with it. With some subplots, from beginning to end, this is the entire plot. One very sticky wicket is what to call Mahiro - he or she. I choose "she". She has an actual girl's body (with every function thereof) - who just happens to have the brain of a boy. You may disagree but that is my convention and I will be using it in this review. This is not intended to make any statements, I just have to pick one and that makes the most sense to me. (I will use "he" for the time before he was turned into a girl. Geez, this is difficult. Oh well.) Onwards... One might be tempted, given this plot, to think a whole bunch of things about it that would be highly in…

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Zeno_Artaxerxes

Cute girls doing cute things... with the twist that one of them is an ex-guy given a drug that transformed him in a middle school girl. Yea, I was scratching my head quite a bit on that aspect of the story... it sounds like bait, and after watching the anime, I still am not that on board on that idea. The story is pretty simple. You've got your average otaku that stays at home all the time and doesn't know much about life and is on his way to become a true hikikomori, if he isn't one already, a genius little sister that can do the impossible even tho she's at high school age, no parents (fr now, where are the parents??? not even a picture of them or anything... ik they said where they were in the anime, but cmon, it feels like they just abandoned these 2), and a wish to help the lose-...…

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julranma

Imagine waking up in the morning and suddenly being a cute girl. That's exactly what happens to 20-year-old hikikomori Mahiro Oyama when one day his sister, the brilliant biochemist Mihari, administered a drug to him that changes his gender. Instead of spending his days gaming and reading hentai magazines, he is now trying on cute dresses, doing his hair and meeting friends. Sounds like a typical sex shift anime à la Ranma 1/2, but it's so much more. Initially shocked by this situation, Mahiro accepts his new role only reluctantly and tries everything to counteract his forced role with his masculinity. However, with time - to his suprise - he finds his way around it very quickly and you notice how he becomes more and more absorbed in the role of the sweet imōto- which even goes so far th…

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MCstorymodeLOVR

This show is critically panned by some people who gloss over it's actual purpose. This is not a fetish show about becoming a girl, nor is it Lolibait. It's a rehabilitation story for a NEET and it's my personal favorite. There is a certain element of escapism for Mahiro, who has his entire life change for the better thanks to his sister. The show speaks to the inadequacy of being the lesser sibling, overcoming that by starting again, and learning to accept change for the better. The only critique I have is that the fan service with certain characters doesn't really make a lot of sense, and should be cut. However, the original manga also has some crazy s*** in it so I can't say it's not accurate to source. 9/10

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Faykey

I am trans now, she/her please :3 This show is both, wacky, questionable, and wholesome. I can't say that it is an amazing show by any means, but if you look past the first episode, and watch it as a non gender bender anime, then it really gets much better to watch through. This show is both, wacky, questionable, and wholesome. I can't say that it is an amazing show by any means, but if you look past the first episode, and watch it as a non gender bender anime, then it really gets much better to watch through. This show is both, wacky, questionable, and wholesome. I can't say that it is an amazing show by any means, but if you look past the first episode, and watch it as a non gender bender anime, then it really gets much better to watch through.

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Smilomaniac

The premise is from the get-go that a man (older brother, true gamer nerd/enthusiast, recluse but ultimately harmless) wakes up having been turned into what looks like a pre-teen girl by his "mad scientist" sister, via a drug. In her room she has a manual on her desk which deetails how she wants to turn him into her little sister, meaning this is entirely deliberate with an agenda. It SOUNDS like this should be a hilarious comedy to give a guy what he deserves in order to appreciate what being a girl or a woman is like, as punishment. That's not at all what it is. This is entirely about a selfish wish from the sister's side to get rid of her nerd brother and gain a cute little sister that she can dress up and take care of and the brother-turned-sister just goes along with it for no good…

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AkiyamaSairei

A lovely anime. What can I say? As a genre I am not quite used to watch, it was interesting to see the differences between life being a boy vs life being a girl and all the funny situations that happened due to this. Music and overall OST is pretty enjoyable. Art and animation were colorful and bright, which combined with a fast-paced narrative, made it very enjoyable to watch. I surely enjoyed every minute of it. This however might not be an anime suited for all. You like it or you don't, and that's fine. I'd definitely recommend that you give it a try and watch at least the 3 first episodes. As for me... Give me 3 more seasons and I'll be sure to devour them!

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