Oniichan wa Oshimai!

Onimai: I'm Now Your Sister!

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Alternative Titles

Synonyms: Onimai, 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: TV
Episodes: 12
Status: Finished Airing
Aired: Jan 5, 2023 to Mar 23, 2023
Premiered: Winter 2023
Broadcast: Thursdays at 23:30 (JST)
Licensors: None found, add some
Studios: Studio Bind
Source: Manga
Genre: ComedyComedy
Themes: CGDCTCGDCT, Magical Sex ShiftMagical Sex Shift, SchoolSchool
Demographic: ShounenShounen
Duration: 23 min. per ep.
Rating: PG-13 - Teens 13 or older


Score: 7.681 (scored by 6647866,478 users)
1 indicates a weighted score.
Ranked: #12392
2 based on the top anime page. Please note that 'Not yet aired' and 'R18+' titles are excluded.
Popularity: #1582
Members: 141,341
Favorites: 1,972

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Ranked #1239Popularity #1582Members 141,341
Add to My List
Episodes: /12


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]


Oniichan wa Oshimai! was released on Blu-ray in two boxes from April 19, 2023, to June 21, 2023.

Episode Videos

Related Anime

Characters & Voice Actors

Murosaki, Miyo

Hioka, Natsumi

Fujimi, Nemu

Sakurai, Mia


Uchida, Yuuya

Nagase, Miyako

Oda, Karin

Kitahara, Yuriko

Nagae, Rika


Hatakeyama, Takurou
Higashi, Mao
Assistant Producer


Opening Theme

Apple Music
Amazon Music
Youtube Music
"Iden Tei Tei Meltdown (アイデン貞貞メルトダウン)" by Enako feat. P-maru-sama. (P丸様。)


Mar 23, 2023
Like many, I was impressed with the debut of Studio Bind and their highly-anticipated, highly-praised, highly-controversial anime adaptation for Mushoku Tensei: Jobless Reincarnation, and like so many more, I was already getting excited for its second season as soon as its first came to a close. However, also like many, I proceeded to be half-disappointed, half-confused when I saw the announcement for Oniichan wa Oshimai! with the name of Studio Bind—the studio which I thought was created for the sole purpose of adapting Mushoku Tensei—so proudly attached. A veteran animator like Shingo Fuji making a directorial debut at a studio I can actually trust to ...
Mar 23, 2023
Mixed Feelings
The only reason why I decided to give this anime a shot is because of the fact it was going to be animated by Studio Bind. Therefore, I thought... "Why not? Looks interesting to me. A gender-bender anime about a failure in life who became a loli by his or should we say 'HER' now to give HER a second chance in life." Now I know what you're thinking, if you look into this out of context, it's essentially a story about a fully grown man who's living alongside middle schoolers who don't have the slightest idea of this PERSON's past, yet it's treating it ...
Dec 11, 2023
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. ...

Interest Stacks


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Recent Forum Discussion

Poll: did this show get you excited
weeaboo5008 - Dec 26, 2023
23 repliesby PeripheralVision »»
Feb 9, 11:44 AM
I love Asahi!
BigBoyAdvance - Feb 7
19 repliesby Floelle »»
Feb 8, 2:36 AM
Poll: Oniichan wa Oshimai! Episode 1 Discussion ( 1 2 3 4 5 ... Last Page )
KANLen09 - Dec 24, 2022
332 repliesby vvinrg »»
Jan 28, 11:25 AM
Mihari seems like an awful person
8bit_meat - Jan 2, 2023
25 repliesby LangleyAsuka »»
Jan 25, 8:17 AM
Poll: Oniichan wa Oshimai! Episode 3 Discussion ( 1 2 3 4 )
Stark700 - Jan 19, 2023
171 repliesby ilikemangaig »»
Jan 22, 2:20 PM