Asahi and Momiji

Asahi and Momiji (あさひともみじ, Asahi To Momiji) is a bonus chapter of Onimai: I'm Now Your Sister!. It was published exclusively in Volume 3 of the manga which was released on September 27, 2019 in Japan, and November 30, 2021 in North America.

Summary
Asahi recalls how she became friends with Momiji in grade school.

Plot
On her first day of grade school, Asahi is eager to make tons of new friends. She says good morning to several people, including Nemu Fujimi, who don't return her affections. She is undeterred though and keeps trying.

She eventually says good morning to Momiji, and believes that Momiji is a samurai due to her topknot. Momiji introduces herself and tells Asahi that it is a pleasure to meet her. Asahi once again says hi to Momiji, calling her Momijiro. Momiji is surprised that Asahi is giving her a nickname already. Asahi asks her if she gets it, as Momiji looks like a samurai, but Momiji doesn't understand and asks Asahi if she can just call her by her real name. Asahi tries to think of what it is and thinks that it is "Jiro", leading Momiji to angrily correct her.

On the way home from school, Asahi follows Momiji saying that she really likes her topknot. Momiji end up thinking that Asahi is a bit of a wierdo. Asahi wishes that she had a topknot as well, and Momiji says that she can do it for her. Instead of giving her one, she gives her two by putting up Asahi's hair into cute side pigtails, saying that it looks better like this. Asahi feels great about them and Momiji smiles at her, having become Asahi's special friend.

From that point forward, the two played together a lot. Asahi even scored the winning goal in a game of soccer, leading to her and Momiji clapping in victory. Momiji notes that Asahi is very good, even better than the boys. She also points out how Asahi is now all muddy, leading Asahi to say that her mom's gonna be so mad. Momiji offers to let Asahi come over to her house and clean up as she lives nearby. Asahi is all for doing that.

At Momiji's house, Momiji tells Asahi to put all of her clothes in the washer, and Asahi agrees. Momiji starts to strip, saying that if Asahi is taking a bath, she will too. Asahi hesitates at that statement. Momiji asks Asahi if she wants to go together, and although Asahi is nervous she says that it's fine. She mentions how she bathes with her brother at home.

When in the bath, Asahi is confused and asks if "it" grows in later, but Momiji has no idea what she's talking about.

It is revealed that Asahi was telling the story to Mahiro, Miyo, and Momiji. Momiji remarks that even for a little kid, you have to admit that that was rude. Asahi laughs off the statement. Mahiro and Miyo are extremely interested in the story, the latter being aroused by it, with both of them thinking that Momiji must've been Asahi's first love.

Characters

 * Mahiro Oyama
 * Momiji Hozuki
 * Asahi Ōka
 * Miyo Murosaki
 * Nemu Fujimi
 * Aoi Tachikawa
 * Akira Nakai
 * Yuta Sakurada
 * Minato Senkawa

Trivia
商业版漫画第三卷附录漫画