Oniichan wa Oshimai!
Onimai: I'm Now Your Sister!
What would you like to edit?

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 ?
Genre: Comedy Comedy
Themes: CGDCT CGDCT, Magical Sex Shift Magical Sex Shift
Serialization: None
Authors: Nekotoufu (Story & Art)


Score: 7.801 (scored by 60406,040 users)
1 indicates a weighted score.
Ranked: #13072
2 based on the top manga page. Please note that 'R18+' titles are excluded.
Popularity: #984
Members: 18,239
Favorites: 850


Ranked #1307Popularity #984Members 18,239
MangaNekotoufu (Story & Art)
Add to My List
Volumes: /?
Chapters: /?


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! is a web manga released on the author's pixiv account since February 25, 2017, and published in print by Ichijinsha since June 27, 2018. The web manga has also been published as doujinshi since May 6, 2017, when the first volume was released at COMITIA 120.

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

Related Manga


Murosaki, Miyo
Fujimi, Nemu
Nagase, Miyako
Tenkawa, Nayuta
Senkawa, Minato


Oct 11, 2022
Preliminary (45/? eps)
Yeah I accept, this is a Gender Bender CGDCT manga and I enjoyed it.

First of all, for my defense. As a zoomer 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 ...
Jul 5, 2019
Preliminary (29/? eps)
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 ...
Aug 26, 2023
Preliminary (71/? eps)
I'm writing this review from the standpoint a trans woman who reaaaaally sees this as unintentionally relatable at time, or wish fulfillment. I know a majority of people are not this way, and that's perfectly fine.

Onimai means a lot to me on an emotional level, it's primarily what cracked my trans egg all the way in 2018 when there were only a few chapters released. I read it in a hotel room at 3am, and promptly forgot the name of the series a week later. Forward to 2022 where I see a gender-bender anime get announced with a name that keeps poking in the back ...

Interest Stacks

20 Entries · 7 Restacks
by vozilla
37 Entries · 141 Restacks
27 Entries · 22 Restacks


Recent News

North American Anime & Manga Releases for July

North American Anime & Manga Releases for July

Here are the North American anime, manga, and light novel releases for July. Week 1: July 4 - 10 Anime Releases Obey Me! Season 2 (Obey Me! The Anime: Season 2) Comp...read more

North American Anime & Manga Releases for October

North American Anime & Manga Releases for October

Here are the North American anime, manga, and light novel releases for October. Week 1: October 4 - 10 Anime Releases Fate/kaleid liner Prisma☆Illya Movie: Licht - N...read more

Recent Forum Discussion

Poll: Onii-chan wa Oshimai Chapter 25 Discussion
Sean- - Feb 28, 2019
3 repliesby MrKitKitty »»
Jan 28, 6:55 AM
Poll: Oniichan wa Oshimai! Chapter 83 Discussion
TKD_Weirdo - Dec 31, 2023
1 repliesby Pitto_ »»
Jan 3, 6:07 PM
Poll: Oniichan wa Oshimai! Chapter 82 Discussion
Pitto_ - Dec 19, 2023
0 repliesby Pitto_ »»
Dec 19, 2023 5:37 AM
Poll: Oniichan wa Oshimai! Chapter 79 Discussion
Kuma - Aug 25, 2023
6 repliesby nicol_osorio »»
Dec 4, 2023 6:18 PM
Oniichan wa Oshimai! Chapter 81 Discussion
Lind_van_Taylor - Nov 25, 2023
0 repliesby Lind_van_Taylor »»
Nov 25, 2023 1:42 PM