お兄ちゃんはおしまい！
ONIMAI: I'm Now Your Sister!
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)
Names
| Original | お兄ちゃんはおしまい！ (japanese) |
|---|---|
| Romaji | Onii-chan wa Oshimai! |
| English | ONIMAI: I'm Now Your Sister! |
| Chinese | 不當哥哥了！ (traditional · via wikidata) |
| Also known as | Onii-chan is Done For! · ONIMAI: Sekarang Aku Kakak Perempuanmu! · อวสานพี่ชาย กลายเป็นพี่สาว · 不當哥哥了！ · Я стал сестрой! · ONIMAI: Ab sofort Schwester! · 오빠는 끝! |
Facts
| Format | TV series · 12 ep · 24 min · 5h total |
|---|---|
| Aired | 2023-01-05 → 2023-03-23 (Winter 2023) |
| Status | FINISHED |
| Studio | Studio Bind |
| Source | Manga |
| Origin | Japan (Anime) |
| Genres | ComedyEcchiSlice of Life |
| Themes | Gender BendingPrimarily Female CastRehabilitationAge RegressionCute Girls Doing Cute ThingsPrimarily Teen CastFemale ProtagonistComing of AgeHikikomoriFamily LifeOtaku CultureSchoolGyaruTomboy |
| Streaming | Crunchyroll · YouTube · Bilibili TV · Laftel |
Reception
| Community score | 7.71 / 10 |
|---|---|
| Bayesian score | 7.70 / 10 |
| Composite | 60.6 |
| On lists | 73,649 |
| Favourited | 3,058 (4.2%) |
| Completion | 73.3% |
| Drop rate | 8.4% |
| In backlog | 27.5% |
| Score spread σ | 1.75 |
Score distribution
131821893330450751,08162,07675,27887,29195,265103,428
Where it places
| Cohort | Value | Tier | Rank |
|---|---|---|---|
| Studio | Studio Bind | — | 8 of 9 |
| Broadcast season | Winter 2023 | B | 15 of 80 |
| Genre | Ecchi | A | 32 of 745 |
| Year | 2023 | B | 71 of 327 |
| Season (all years) | Winter | B | 196 of 1,557 |
| Genre | Slice of Life | B | 279 of 1,578 |
| Era | Early 2020s | B | 307 of 1,596 |
| Genre | Comedy | B | 400 of 3,488 |
| Length | Single-cour | B | 413 of 2,668 |
| Source material | Manga | B | 545 of 3,025 |
| Format | TV series | B | 582 of 3,322 |
| Origin | Japan | B | 909 of 7,157 |
Key staff
| Director | Shingo Fujii |
|---|---|
| Series composition | Michiko Yokote |
| Character design | Ryou Imamura |
| Original creator | Nekotofu |
AniList id 147864 · MAL id 51678 · record updated 2026-08-27