Danica Davidson
December 5, 2022 
The manga ONIMAI: I’m Now Your Sister! (a.k.a. Onii-chan wa Oshimai! in Japanese) is getting an anime adaptation that will debut on January 5. A trailer for it has dropped, and in it you can hear the opening theme song “Identeitei Meltdown” being performed by P Maru-sama and cosplayer Enako.
You don’t hear it in the trailer, but the ending theme song will be “Himegoto * Cry Sisters” and performed by Marika Kōno, Kaori Ishihara, Hisako Kanemoto, and Minami Tsuda.
The trailer lets us know that Kana Yūki will play Asahi Ōka and Natsumi Hioka will play Miyo Murosaki. These cast members had formerly been revealed: Marika Kōno plays Mahiro Oyama, Kaori Ishihara plays Mihari Oyama, Hisako Kanemoto plays Kaede Hozuki, and Minami Tsuda plays Momiji Hozuki.
The anime is being made at Studio Bind, with Shingo Fujii, who has been an episode director for Mushoku Tensei: Jobless Reincarnation, directing the whole series. Credit for music composition goes to Daisuke Achiwa and Arisa Okehazama. The person in charge of series scripts is Michiko Yokote, who is known for working on Prison School Love All Play and Tsurune. Credit for character design goes to Ryo Imamura, who has also worked on Mushoku Tensei: Jobless Reincarnation.
The manga is published in English by Kodansha, though only digitally, not physically. Kodansha gave this description of the plot:
“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: ANN
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Danica Davidson is the author of the bestselling Manga Art for Beginners with artist Melanie Westin, plus its sequel, Manga Art for Everyone, and the first-of-its-kind manga chalk book Chalk Art Manga, both illustrated by professional Japanese mangaka Rena Saiya. Check out her other comics and books at www.danicadavidson.com.
