Work Text:
Imagine the twins when they were little, female Atsumu and male Osamu.
Whenever they played games like house or save the princess, Atsumu always wanted to be the daddy or the knight and Osamu always wanted to be the mommy or the princess. (Though, the princess Osa and knight Atsu always ended up fighting more than knight Atsu and dragon Dodo.) And this tendency to swap roles carried through their entire childhood. Atsumu always wanted to play with the boys, play the boys sports, would try to go towards the boys side during gym. Osamu always wanted to play with the girls, be with the girl managers or on the girls teams, would try to sneak over to the girls table during work time.
When volleyball came around in high school, the differences really started to show.
Atsumu fought tooth and nail to be allowed on the boys’ volleyball team; she trained as hard as she could to meet all the absurd physical tests they were putting her through, fought for weeks with the principal and coaches and teachers with Osamu at her side the entire time.
And Osamu was scouted specifically; they wanted him on the team more than anything. And it was a condition of his that Atsumu be allowed to come with him, or he wasn’t doing shit with the Inarizaki volleyball team. In the end, with Aran and Kita and the captain’s help, the twins were both put on the team their first year of high school.
And then, the habits started to show.
The team found it very odd when Atsumu was legitimately offended that she wasn’t allowed to change in the clubroom with the guys. And Osamu was visibly uncomfortable changing in there, especially without his twin. He would always hide his chest without thinking much about it, glaring at anyone who stared for too long. After the third week of their weird behavior, the coaches compromised to let the twins have their own separate space to change.
The first year goes by just fine when people get used to the twins. Aran still stands by their side anytime someone tries to hurt them or throw them off the team at any competitions or camps; the twins still bicker and fight and sync up on the court; the team still gives them weird looks on occasion for their particularly odd habits.
And then, the new year begins and new players are brought on. A handful of first years and one new second year transfer from the city.
By now, the twins are used to their space in the team.
They’d changed with time, of course.
Atsumu stopped wearing regular bras, only wearing sports bras and sports compression tops everywhere she went. She ditched the girl’s uniform, claiming it was too damn cold to be wearing a skirt all the time and she didn’t like the guys staring at her legs — which she’d stopped shaving. Her hair was already typically short, but she’d eventually just chopped it all off to match her brother’s. She didn’t pluck her eyebrows much anymore, either. During team outings, she wore men’s fashion (she looked damn good, too) and she didn’t wear much makeup. Her rowdy personality was strong as ever. Oh, and she wore briefs and used men’s deodorant.
Osamu started wearing a thin tank top under all his shirts, since Atsumu had been so insistent they start changing in the clubroom since she was given permission as long as she had the compression top on. Of course, Atsumu still picked fights with anyone who looked at Osamu with anything but respect or indifference besides their friends. Osamu kept his quiet personality, though instead of how cold it had seemed in the beginning, the team was starting to realize that it was more… soft, in a way. He always smelled sweet, like fruit or flowers or other perfumes. He stopped wearing the school jacket almost every guy wore, instead picking a school sweater that was definitely two sizes too big; it hid all the muscles in his arms that girls would stare at and fawn over. When they went out, Osamu would be in a more andrgynous — sometimes daringly outright feminine — street fashion; otherwise it was huge hoodies and form-fitting jeans. Some of the team started to suspect he wore makeup and plucked his brows at least a little bit.
When they went to the malls and second-hand shops, the twins would sometimes stray from the group; and they were usually found in the women’s clothes and makeup where Osamu was a bit red in the face as Atsumu flicked through things and studied her twin. The looks from Aran always told everyone crystal clear not to say a damn word.
Anyways, the new year.
It comes and brings new people. When they come to their first practice, of course the twins are already there.
In the middle of a wrestling match.
Immediately, the newbies watch Aran age 10 years and Kita snicker a little.
Aran trudges up to the twins and grabs Atsumu by the collar of her practice shirt. He gets a foot on Osamu’s shoulder over his oversized team jacket. And he yanks Atsumu back while shoving Osamu away. The twins immediately turn their indigance on their best friend, shouting their defenses.
But, once Kita comes over with a raised eyebrow, they quickly shut up and just glare at each other.
The newbies deem it safe to approach. And before anyone can say anything, Suna speaks up with a mild curiosity.
“I thought they didn’t let girls on the team.”
Kita and Aran stiffen, and the other upperclassmen shuffle away from the transfer.
Atsumu turns with a fire in her eyes. “Excuse me, city runt?” she growls. “I earned my spot on this damn team and—”
Suna gives her a weird look. “What are you talking about? I meant her.”
And all of the upperclassmen seem to have a collective confusion as this city boy stares dead at Osamu.
“You’re the girl from 2-B, right? The one who sits in the back of the third row by the windows. We’re in the same class.”
The entire upperclass is completely silent. Even Atsumu is looking between Osamu and Suna. She’s studying Osamu as he gets redder and redder in the face, an odd discomfort showing next to what Aran and Atsumu can tell is quiet happiness.
Then, Suna starts another earthquake.
“I saw you arguing with your brother during second break. I guess it makes sense that you’d be strong enough to throw him around if you’re a spiker.”
Now, everyone’s looking at Atsumu. And her face is suddenly almost blank, like she’s blue screened and is trying to reboot.
Osamu scooches his way over to her, quietly tugging on the hem of her shirt. He leans in and whispers something, frowning when he pulls back. Whatever he says kicks her back up to operating and she nods.
“We’re goin’ to the nurse,” she announces.
And without giving any chances for objection, she grabs Osamu’s hand and pulls him out of the gym
Thus, the switches have been flipped and their gender crisis begins.