Chapter Text
The night air was cool, but Atsumu’s skin was hot to the touch, coated in a thin sheen of sweat. He’d stayed late after practice in the All-Japan Youth camp to practice his sets, while his brother went back to stay in their dorm.
A lot of people were surprised that the Miya twins had gone to the camp. It was their first year after all. It was a shock they were even invited.
The blond was setting to a wall, when suddenly—
BAM!
The setter turned around, to see none other than Sakusa Kiyoomi practicing on the other side of the court.
“Woah! You’ve got a nasty spike, Sakusa-san!” Atsumu complimented him with a thumbs up. Kiyoomi simply nodded and went back to practicing.
It was silent for half an hour, save for the sound of volleyballs bouncing against skin or walls. Silent, until Atsumu spoke. “Sakusa-san. Can ya hit some of my sets?”
“Of course I can, Miya.”
Of course, Atsumu Miya wanted nothing other than to test his rival. He deliberately sent a toss that was a little too high, a little too quick. Kiyoomi adjusted with ease, his freakishly bendy wrists moving fast to slam the ball into the floor with a BAM!
Followed by another perfect spike. Then another, then another.
It was then Kiyoomi realized that despite Atsumu’s loud and enthusiastic personality, his sets were extremely clean, precise and tailored fully to match his wrists and still bring out the best in all his spikes.
It was then Atsumu realized that despite Kiyoomi’s quiet and perfectionistic nature, his spikes were incredibly strong, aimed and powerful yet could still easily dodge blocks.
They’d been practicing together for over an hour, now panting and sitting on the bench. Since the start of their short break, all they talked about were the mistakes other players made earlier during training. It started with Atsumu pointing out a subtle flaw in another player's footing, and Kiyoomi’s eyes lit up with a cold, sharp interest.
"If ya aim the float serve to his left, his balance collapses," Atsumu murmured, spinning a volleyball on his finger. "He looks like a newborn deer tryna fix it. It's hilarious."
Sakusa let out a rare, faint huff that was dangerously close to a laugh. "And if I block his recovery line, he'll tilt for the rest of the set. He has zero mental fortitude. Let's do it tomorrow."
“Let’s,” Atsumu smirked. His eyes gleamed with contempt.
"The media is going to be annoying if we play like this tomorrow," Kiyoomi muttered, looking disgusted at the mere thought. "They'll want some pathetic, wholesome narrative about the 'New Generation Power Duo'."
Atsumu gagged. "Ugh, barf. I'd rather swallow a volleyball. Besides, it's way funnier if they think we hate each other's guts. Imagine the look on 'Samu's face if he thinks I'm miserable every time I have to set to ya." Kiyoomi’s lips twitched upward into a malicious smile. "A fake rivalry. It keeps the press away, and it keeps everyone else off-balance."
"Perfect," Atsumu grinned, holding out a fist. Kiyoomi, true to form, didn't touch it, instead just tapping the top of Atsumu's fist with the cap of his water bottle.
Game on.
That night, the two made two goals for their friendship. One, absolutely destroy everyone else on the court, and two, keep their friendship a secret. Of course, what could you expect from two famous high school athletes? They bonded over being sadistic assholes who love toying with other players.
The next morning was chaos. Atsumu and Kiyoomi bickered all day, but teamed up perfectly to defeat everyone else. They were a power duo, anyone who saw them could admit it.
Even after the All-Japan camp ended and they went back to their respective schools—Atsumu to the loud, chaotic gym of Inarizaki in Hyogo, and Kiyoomi to the strict, clinical discipline of Itachiyama in Tokyo—the pact didn't fade. If anything, the distance just made the game more entertaining.
Their texts weren't sweet or normal. They didn't send "good morning" messages. Instead, their chat was a relentless, running log of psychological warfare. Atsumu would send blurry, zoomed-in videos of opposing spikes just to text: Look at his elbow. Disgusting. You’d let him score? And Kiyoomi would reply hours later with a cold, precise breakdown: His form is trash, and your receiver looks like he's trying to catch a chicken. Tell your brother he's slow.
They fed each other's arrogance from miles away. For Atsumu, Kiyoomi was the only person who understood the sheer, intoxicating high of absolute perfection on the court. For Kiyoomi, Atsumu was the only setter alive who didn't cry when he demanded the impossible. They were both elite, cruel, and absolutely obsessed.
Eventually, Sakusa turned into Omi, and Miya turned into Tsu. The shift happened three months after the camp, during a rainy weekend in October. They had spent two hours on a late-night phone call, completely dismantling the playstyles of a rival school. By the end of it, Atsumu was laying upside down on his bed, listening to the rare, relaxed cadence of Kiyoomi's voice over the speaker.
"Hey, Omi-Omi," Atsumu said casually. "We've been tearin' everyone else to pieces for months. But I think I'm bored of doin' it as just friends."
There was a long pause on the other end of the line. The silence stretched so long Atsumu thought the call had dropped, until Kiyoomi spoke, his voice quiet but dangerously sharp. "Are you proposing we make it official, Tsu? Because if we do, I expect total compliance. I don't tolerate sloppy play, and I don't tolerate sloppy boyfriends."
Atsumu let out a loud, delighted laugh, his eyes bright in the dark room. "Compliance? Bold of ya to assume yer the one callin' the shots. But yeah. Let's do it."
"Fine," Kiyoomi muttered, though the slight softening in his tone gave him away. "But the pact stands. If anyone asks, I still despise you."
“Deal,” Atsumu grinned. For the next year and a half, they perfected the art of the double life. In public, they were bitter rivals. In private, however, they quietly adjusted their lives to fit around each other's sharp edges. Because they were hours away, their domesticity existed in the quiet hours.
It was Kiyoomi staying on FaceTime for hours without saying a word, the phone propped up on his desk while he studied, just so Atsumu could have the comforting, rhythmic background noise of turning pages while he drifted off to sleep. It was Atsumu, who usually couldn't sit still for five minutes, patiently sitting at his desk to write out physical, handwritten letters because Kiyoomi really liked receiving letters as gifts. They learned each other’s unspoken rules.
Kiyoomi stayed up comforting Atsumu when he learned his twin wouldn’t pursue volleyball with him in the future. Atsumu reassured his lover he wouldn’t find someone else while Kiyoomi went to college after high school.
Of course, being a secret got hard when they fought. Neither of them could seek advice from anyone else, but it always worked out.
Then came the care packages. Every two weeks, a plain brown box would arrive at Miya household for Atsumu. Inside, hidden beneath layers of thick bubble wrap and plastic sheets would be small containers of fatty tuna that Kiyoomi cooked himself with care. Every two weeks, Kiyoomi would open his front door out in Tokyo to find a neatly wrapped package of umeboshi with little nori faces or home-cooked Hyogo dishes that Atsumu cooked, wrapped in three separate layers of airtight plastic wrap.
When they did see each other at national tournaments, the domesticity became physical, tucked away in empty stairwells and locked storage rooms. The first time they met up in secret after a match, Atsumu had expected a continuation of their sharp banter. Instead, the moment the heavy metal door clicked shut behind them, Kiyoomi had dragged him by the jacket into his chest.
He didn't care about the sweat. He didn't care about the public gym germs. He just buried his face into the crook of Atsumu’s neck, breathing him in, while Atsumu’s arms wrapped tight around his waist, holding him like he was the only anchor in a crowded stadium. They were still sadistic pricks to the rest of the world. But to each other, they were safe.
By the time they reached their second year—approaching the two-year mark of their secret relationship—the initial thrill of just keeping it a secret started to wear off. They were older, more arrogant, and significantly more bored. That was when the real game started. They didn't just want to hide it anymore; they wanted to see exactly how much they could get away with right under their teammates' noses before anyone actually noticed.