ONIMAI: I’m Now Your Sister revealed a non-credit version of the opening and ending. Both videos feature catchy songs: the opening theme song is “Identity Meltdown” by Enako and Pmaru-sama while the main cast (Marika Kono, Kaori Ishihara, Hisako Kanemoto and Minami Tsuda) is singing “Himegoto ＊Crisisters,” which serves as the ending theme.
Akio Watanabe (Monogatari, Zaregoto, Higurashi (New), and more) directed and storyboarded the opening. Ryo Imamura and Takuma Yamazaki are credited as animation directors.
Studio Bind (Mushoku Tensei: Jobless Reincarnation) is animating the gender-bender story. Shingo Fuji is directing, with Michiko Yokote on the series composition. Ryo Imamura is in charge of the character designs. Daisuke Achiwa and Alisa Okehazama are composing the music.
The anime is based on a manga by Nekotofu. The manga originally started serialization online but is also being published in Ichijinsha’s Monthly Comic Rex magazine. Kodansha USA has been publishing the manga in English since last year and describes the plot as:
Mahiro Oyama was just a normal 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: Official Website
©Nekotofu/Ichijinsha/Onimai Production Committee