ONIMAI: I'm Now Your Sister! Anime's 2nd Video Reveals More Cast & Staff, January 5 Debut

The official website for the television anime of Nekotofu's ONIMAI: I'm Now Your Sister! (Onii-chan wa Oshimai!) manga unveiled the second promotional video and visual for the anime on Monday. The video reveals more cast and staff members, as well as the anime's January 5 premiere. It also previews the opening theme song "Identeitei Meltdown."

The new cast members include:

Kana Yūki as Asahi Ōka, Momiji's cheerful classmate

Natsumi Hioka as Miyo Murosaki, Momiji's slightly shy classmate

Previously announced cast members include:

Marika Kōno as protagonist Mahiro Oyama

Kaori Ishihara as Mahiro's sister Mihari Oyama

Hisako Kanemoto as Kaede Hozuki, Mihari's former middle school classmate

Minami Tsuda as Momiji Hozuki, Kaede's younger sister

The additional staff members include:

• Art Director: Masayo Kobayashi
• Color Key Artist: Makiko Doi
• Compositing Director of Photography: Akane Fushihara
• Editing: Yūji Oka
• Sound Director: Kōhei Yoshida
• Sound Effects: Takuya Hasegawa
• Music: Daisuke Achiwa, Arisa Okehazama

The anime will premiere on the AT-X channel on January 5 at 11:30 p.m. (9:30 a.m. EST), and it will also run on Tokyo MX and BS11.

Shingo Fujii (Mushoku Tensei: Jobless Reincarnation episode 11 storyboards, director) is making his series directorial debut with the anime at Studio Bind. Michiko Yokote (Shirobako, Prison School Love All Play, Tsurune) is in charge of series scripts. Ryo Imamura (Mushoku Tensei: Jobless Reincarnation episode 11 animation director) is designing the characters. EGG FIRM is producing the series.

Multi-genre entertainer P Maru-sama and cosplayer Enako are collaborating to perform the opening theme song "Identeitei Meltdown," while the "Onimai Sisters" (the main characters' voice actresses: Marika Kōno, Kaori Ishihara, Hisako Kanemoto, Minami Tsuda), perform the ending theme song "Himegoto * Cry Sisters."

Kodansha Comics is publishing the manga digitally in English, and it describes the story:

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!

The manga began as a self-published work by Nekotofu in 2017, which they published through pixiv and other places online. Nekotofu launched a regular serialization of the manga in Ichijinsha's Comic Rex magazine in April 2019. Ichijinsha published the manga's sixth compiled book volume and its second anthology volume on the same day on April 27. Kodansha Comics released the sixth volume in English on October 25.

Sources: ONIMAI: I'm Now Your Sister! anime's website, Comic Natalie