Oniichan wa Oshimai!
Onimai: I'm Now Your Sister!
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Oniichan wa Oshimai!

Alternative Titles

Synonyms: Onii-chan is Done For
Japanese: お兄ちゃんはおしまい!
English: Onimai: I'm Now Your Sister!
More titles


Type: Manga
Volumes: Unknown
Chapters: Unknown
Status: Publishing
Published: Jun 27, 2018 to ?
Genres: Comedy Comedy, Slice of Life Slice of Life
Themes: Doujinshi Doujinshi, Gender Bender Gender Bender
Serialization: None
Authors: Nekotoufu (Story & Art)


Score: 7.721 (scored by 29132,913 users)
1 indicates a weighted score.
Ranked: N/A2
2 based on the top manga page. Please note that 'R18+' titles are excluded.
Popularity: #1716
Members: 8,738
Favorites: 375

External Links

Ranked N/APopularity #1716Members 8,738
MangaNekotoufu (Story & Art)
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Mahiro Oyama was just a normal erotic-game loving dude...until he woke up one morning as a woman! Turns out his mad-scientist little sister, Mihari, tried out one of her new experiments on him...with a disastrous outcome, as far as Mahiro's concerned! But Mihari is as determined to study him as he is determined to go back to his shut-in, game-playing life, and one thing's for sure...life is going to get a whole lot weirder from here on out!

(Source: Kodansha USA)


Oniichan wa Oshimai! has been published digitally in English as Onimai: I'm Now Your Sister! by Kodansha USA since August 31, 2021.


Ouka, Asahi
Fujimi, Nemu
Hozuki, Momiji

More reviewsReviews

Jun 13, 2019
Kil-Kun (All reviews)
Yeah I accept, this is a Gender Bender CGDCT manga and I enjoyed it.

First of all, for my defense. As a millennial I grew up in the era of Cute girls doing cute things (CGDCT), not in generation of Cowboy Bebop, Trigun and Joe. So I enjoy this just like I would any other series, unlike the elitists I don't complain, I accept whatever I'm given.

So this is the story of a NEE- *ahem* "In-Home Security Guard" He was a useless member of the society so to fix that can you guess what his sister did? She drugged him and turned him into a read more
Jul 5, 2019
Verthelion (All reviews)
How do you like your eggs?* Scrambled? Poached? Forcibly hatched? Well then you've come to the right place, cause this is a nice and cutesy SOL genderbender story! I like nice and cozy stuff like this. Though one of the gags is a little weird. Like they say, "if I had a nickel for everytime someone peed themselves during this story I would have 3 nickels; that isn't much, but it's a little strange that it happened that many times." I guess he wants to call attention to the smaller bladder of girls?

*If you have no idea what the fuck i'm talking about, visit the read more
Dec 23, 2020
maryyyyyy (All reviews)
Here we are again, wondering what the hell we're reading. Maybe you're like me, visiting this page after having read Oniichan was Oshimai. Maybe you're curious. Well, don't worry. This is a judgment-free zone. We're all trash here: every single person who viewed this page. In all seriousness, this is a strangely adorable comedy about a guy learning to live as a girl. It's cute, and that's really all we can ask for at the end of the day. There's a wide cast of all adorable girls and is pretty well-drawn. The characters follow a variety of archetypes and interact well together. It provides for read more


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