Synopsis
When lazy, erotic-game loving Mahiro Oyama is transformed into a girl by his younger scientist sister's experiments, he becomes determined to change back, only to recognize that with his new opportunity, he may want to turn his life around.
Series Information
- First Aired
- 2023
- Last Aired
- 2023
- Seasons
- 1
- Episodes
- 12
- Episode Length
- 24 min
- Genre
- Animation, Comedy
- Network
- AT-X
- Status
- Ended
- Rating
- 7.4 / 10 (66 votes)
Top Cast
Marika Kouno
Mahiro Oyama (voice)
Kaori Ishihara
Mihari Oyama (voice)
Hisako Kanemoto
Kaede Hozuki (voice)
Minami Tsuda
Momiji Hozuki (voice)
Kana Yuuki
Asahi Ohka (voice)
Natsumi Hioka
Miyo Murosaki (voice)
Official Trailer
Ready to watch ONIMAI: I'm Now Your Sister!?
All seasons & episodes — free, HD, no signup.
▶ Watch ONIMAI: I'm Now Your Sister! FreeSimilar Shows
Plunderer
2020 ★ 8.3
Saki
2009 ★ 5.6
Death Stranding Isolations
Eren the Southpaw
2026 ★ 7.0
Tsuide ni Tonchinkan
1987 ★ 6.0
Senpai Is an Otokonoko
2024 ★ 7.1
The Magical Girl and the Evil Lieutenant Used to Be Archenemies
2024 ★ 7.1
Otherworldly Munchkin: Let's Speedrun the Dungeon with Only 1 HP!
The Case Book of Arne
2026 ★ 6.5
True Beauty
2024 ★ 8.3
Bogus Skill «Fruitmaster» ~About that time I became able to eat unlimited numbers of Skill Fruits (that kill you)~
2025 ★ 7.2
Teach You a Lesson
2026 ★ 9.4
African Office Worker
2017 ★ 7.0
If My Favorite Pop Idol Made It to the Budokan, I Would Die
2022 ★ 6.7
You May Also Like
The Dangers in My Heart
2023 ★ 8.6
School Rumble
2004 ★ 7.5
Daily Lives of High School Boys
2012 ★ 8.0
Shikimori's Not Just a Cutie
2022 ★ 7.7
The Disappearance of Nagato Yuki-chan
2015 ★ 8.0
Alya Sometimes Hides Her Feelings in Russian
2024 ★ 8.0
Wasteful Days of High School Girls
2019 ★ 7.7
Pseudo Harem
2024 ★ 8.1
Himouto! Umaru-chan
2015 ★ 8.2
Non Non Biyori
2013 ★ 7.8
My Friend's Little Sister Has It In for Me!
2025 ★ 7.3
Miru Tights
2019 ★ 6.1
Maison Ikkoku
1986 ★ 7.6
Kinmoza!
2013 ★ 6.4
More Animation Series
The Simpsons
1989 ★ 8.0
American Dad!
2005 ★ 7.0
Family Guy
1999 ★ 7.4
Teen Titans Go!
2013 ★ 6.4
Rick and Morty
2013 ★ 8.7
Regular Show
2010 ★ 8.6
Bleach
2004 ★ 8.4
Adventure Time
2010 ★ 8.5
Miraculous: Tales of Ladybug & Cat Noir
2015 ★ 8.1
Mushoku Tensei: Jobless Reincarnation
2021 ★ 8.4
South Park
1997 ★ 8.3
The Fairly OddParents
2001 ★ 7.6
Hunter x Hunter
2011 ★ 8.7
Futurama
1999 ★ 8.4
More with Marika Kouno
Re:ZERO -Starting Life in Another World-
2016 ★ 8.1
Kaguya-sama: Love Is War
2019 ★ 8.5
Seirei Gensouki: Spirit Chronicles
2021 ★ 8.2
Your Lie in April
2014 ★ 8.6
Sword Art Online Alternative: Gun Gale Online
2018 ★ 7.7
Digimon Adventure:
2020 ★ 7.6
A Livid Lady's Guide to Getting Even: How I Crushed My Homeland with My Mighty Grimoires
2026 ★ 7.5
D_Cide Traumerei the Animation
2021 ★ 7.3
Chillin' in Another World with Level 2 Super Cheat Powers
2024 ★ 7.3
The Saint's Magic Power Is Omnipotent
2021 ★ 7.8
Love Flops
2022 ★ 6.7
Blue Archive the Animation
2024 ★ 6.3
Dr. STONE
2019 ★ 8.5
In Another World with My Smartphone
2017 ★ 7.2
Trending Now
Silo
2023 ★ 8.2
The Gentlemen
2024 ★ 7.8
The Grand Tour
2026 ★ 9.6
Lanterns
2026 ★ 8.3
Dark Matter
2024 ★ 7.8
Reacher
2022 ★ 8.1
Stuart Fails to Save the Universe
2026 ★ 9.0
Furious
2026 ★ 7.2
MobLand
2025 ★ 8.3
Chad Powers
2025 ★ 8.0
One Piece
1999 ★ 8.7
Spider-Noir
2026 ★ 8.4
Ted Lasso
2020 ★ 8.4
House of the Dragon
2022 ★ 8.4
Popular This Week
Watch What Happens Live with Andy Cohen
2009 ★ 4.9
The Mentalist
2008 ★ 8.4
Coronation Street
1960 ★ 5.4
Home Alone
2013 ★ 7.5
Lioness
2023 ★ 8.1
The Tonight Show Starring Jimmy Fallon
2014 ★ 5.8
Law & Order: Special Victims Unit
1999 ★ 8.0
The Late Show with Stephen Colbert
2015 ★ 6.1
Criminal Minds
2005 ★ 8.3
El conquistador
2005 ★ 5.7
The Tonight Show Starring Johnny Carson
1962 ★ 7.5
Tagesschau
1952 ★ 6.8
The Rookie
2018 ★ 8.5
Game of Thrones
2011 ★ 8.5
Explore related titles
Frequently Asked Questions
Where can I watch ONIMAI: I'm Now Your Sister! online for free?
You can watch every season and episode of ONIMAI: I'm Now Your Sister! online for free in HD on FreeFlix. No signup required.
How many seasons of ONIMAI: I'm Now Your Sister! are there?
ONIMAI: I'm Now Your Sister! has 1 season and 12 episodes, all available on FreeFlix.
Is ONIMAI: I'm Now Your Sister! available in HD?
Yes, all episodes of ONIMAI: I'm Now Your Sister! stream in HD with multiple backup sources.
Do I need an account or subscription?
No. FreeFlix is 100% free with no registration, payment, or account required.