Mahiro's Self Image

Mahiro's Self Image (まひろとアイデンティティ, Mahiro to Aidentiti) is Chapter 3 of Onimai: I'm Now Your Sister. It was originally published on Pixiv on April 22, 2017.

Summary
After Mahiro gets turned on by a BL game, Mihari convinces her to go outside and exercise to feel better.

Plot
Mahiro groans and lets out a few tears. Mihari asks her what's wrong, and Mahiro says that she can't take it. She claims that this unbearable "no-fapping" life is finally getting to her. She explains that she wanted a laugh, so she tried a BL (Boy-Love) game that she bought by mistake and got turned on by it. Mihari is secretly amazed.

Mahiro continues crying saying that she never knew that she had it in her. Mihari tries to tell her not to care as she's a girl now (and girls are expected to be turned on by things like that), but Mahiro asks how she could not care. Mihari wonders to herself if Mahiro's newfound girlishness is expanding to her tastes, as she knows that Mahiro likes the girl's clothes more than she lets on. She notes though that the BL is unexpected.

Mihari says that if Mahiro is looking for a change of pace she knows just the thing. She says that it might be a little advanced for her, but at this point Mahiro is willing to do anything. Mihari says that it is exercise, which causes Mahiro to break down in tears again while refusing.

Mahiro asks what Mihari thinks that a self-proclaimed "Own-Home Security Guard" does, the term of which Mihari is intrigued about. Mihari notes that it is a great excuse to get some sun, but Mahiro insists that she'll burn up. Mihari pulls out the big guns by asking if she'd rather leave Mahiro to her BL game, and Mahiro reluctantly agrees wondering why she has to be the one in this situation.

Soon after, Mihari dons a tracksuit and gives one to Mahiro and drags her outside. Mahiro is overwhelmed by the sunlight and collapses, in disbelief that she is leaving the house for the first time in two years like this. Mihari thinks to herself that she's thankful for BL games. She tells Mahiro that she'll feel better after she works up a sweat. Mahiro then grips Mihari's arm begging her just to not leave her, which leaves Mihari very suprised. She assures Mahiro that she wouldn't dare leave her and will be right there beside her which leave Mahiro feeling assured. Mihari notes that if anyone saw them right now, they would have no idea that it was Mihari who was the younger sister.

Mihari says that they will start with some light jogging alongside the river and Mahiro agrees. They begin, but Mahiro quickly falls behind and yells for Mihari to wait up. Mihari slows down and apologizes, having forgotten that Mahiro is less capable now in a number of ways. Mahiro thinks to herself that even if she was in tip-top shape she still couldn't keep up.

She notes how Mihari is a very talented woman, one could even say that she is too talented. Mahiro explains that from the day Mihari could walk, she was an athlete, and that there are track records she set in middle school that remain unbroken. Her grades were also at the top of her class which led to her being accepted to a university at a young age. Mahiro notes that next to such an accomplished older sister, and older brother like her was a disappointment. She notes that all the judging stares from the people around her just needled her in. Now she has become her sister's guinea pig. She thinks that maybe it is time to forget about being her older brother and be happy as she is now.

Mahiro suddenly stops running and Mihari asks what's wrong. Mahiro lets out a few tears remarking that her nipple hurt because they're rubbing against her shirt. Mihari immediately understands and asks Mahiro why she's not wearing anything underneath it, as she gave her underclothes. Mahiro remarks that she couldn't do it, as she had to draw the line somewhere. Mihari is fine with that, but suggests that they instead go bra shopping, something that Mahiro becomes frightened at the thought of.

At a lingerie store, Mihari asks a saleslady to help Mahiro saying that its her first time, and the saleslady is more than happy to do so. The saleslady tells Mahiro to relax and starts measuring her chest, much to Mahiro's surpise. She then remarks to Mahiro that she needs to touch her, which also freaks Mahiro out.

After much fiddling, Mahiro is fitted for a sports bra which Mihari says looks great. Mahiro ultimately is left in a state of shock.

The next day, Mahiro refuses to get out of bed. Mihari in frustration asks what happened to exercising. Mahiro just says that she can't do it anymore claiming that it is hazardous to her self image. Mihari sighs a bit, noting that Mahiro has gone two steps foward yet one step back.

Mahiro ultimately decides to just bind her chest with sarashi for now.

Characters

 * Mahiro Oyama
 * Mihari Oyama
 * Hiyori

Trivia

 * First appearance of Hiyori, but she isn't named in the chapter. Her name was revealed later in the anime adaptation of the chapter.