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Atsumu was 5 when Sakusa Kiyoomi moved next door. He and Osamu were in the yard tossing a volleyball back to one another when a fancy car slid to a stop a couple feet down the street.
"That's a nice car 'Samu," Atsumu hummed as he caught the ball and held it against his side.
"Yes it is 'Tsumu. Do ya think someone's finally buyin' that old house?" Osamu wondered beside him.
The two continued to stare until a tall man stepped out of the driver's side. The black haired man was obviously an alpha judging by the strong scent of lavender and honey.
Atsumu shuddered, he has never seen such an intimidating man before.
From the passenger side, a slender woman with curly brown hair elegantly stepped out, summer dress ruffling slightly in the country wind.
The couple were mates, if the bite mark on the woman's scent gland was anything to guess by.
The last person stepped out of the car and immediately the two boys felt the air in their lungs freeze.
The kid was around their age, probably slightly older than Atsumu. He had curly black hair and porcelain skin. In Atsumu's eyes, he was the most beautiful person he has ever seen.
At his side, Osamu gulped with a deep blush on his chubby cheeks.
That was how the Miya twins met Sakusa Kiyoomi.
Their mother was excited to have new neighbors. Her omega cinnamon scent stunk up the place in waves, making the two slide on masks before their noses start bleeding.
Contrary to what they both thought, the tall alpha man wasn't as scary as they expected. When their mother dragged them over for a greeting, the new family welcomed them with open arms.
Their mother passed them a bowl of cookies and immediately began gossiping up a storm with the woman.
Off to the side, the twins shuffled their feet awkwardly as they stood before the beautiful boy.
Well this wasn't awkward at all.
The boy clutched his jacket closer to his body and fixed his mask. One thing they both noticed about him, he was bundled up tightly in masks and gloves.
"Ah...why are ya wearing gloves? It isn't that cold outside," Atsumu, ever the oblivious asshole, questioned with a small head tilt.
Osamu elbowed him in the side and leaned over to his ear.
"I think he has Mysophobia you idiot. Don' ask intrusive questions," he whispered.
"Myso- what now? Is that a disease or somethin?" Atsumu never was the smart twin.
The boy across from them clear his throat. "I don't have a disease."
And boy did he sound absolutely disgusted at the thought. His face pinched up under his mask and his arms crossed over his chest like he was protecting himself.
"Oooo k? Well I'm Atsumu 'n that's Osamu, let's be friends okay?" He grinned widely, small fangs glistening with his excited eyes.
"I can introduce myself ya dummy," Osamu mumbled and shoved his face into his jacket.
That should have been one of the many hints. Osamu never had any interest in talking, let alone introducing himself to others. He really should learn to be more aware.
Later that night he stared up at his brothers bunk with wide eyes. His teddy bear was clutched tightly to his chest before he threw it while squealing quietly into his hands and kicking his feet.
"What's wrong with ya? Go ta bed," Osamu's muffled groan came from above him. He was probably sleeping on his face again.
"I have a crush on Sakusa, 'Samu!" Atsumu realized with an amazed blush.
Silence seemed to thicken the air between them.
"I do too," Osamu whispered after a few moments.
Atsumu jumped up so fast he bumped his head off Osamu's bunk. As he was whining in pain, his brother climbed down the ladder and sat down beside him.
When his head quit hurting, he sat up to stare at his brother.
It's true they have always liked the same things, same color, same animal, but he never thought they would like the same guy.
"I like him a lot 'Samu..." He whispered.
"...Me too."
"My heart pounds everytime he looks at me! He's cute and fluffy looking and I want to be his!" Atsumu flailed his arms angrily.
"...I do too."
Atsumu grunted in annoyance and threw his blanket over his head. He didn't want to look at his brother right now.
"Then I guess we're competing over him," Atsumu finally declared.
"That sound like too much of a pain," Osamu groaned and flopped down beside him.
"Why are ya scared?" Atsumu challenged, peeking his head out to glare at his brother.
One thing that riled Osamu up was a challenge, yet another thing they had in common.
"I'm going ta make that boy fall fer me if it's the last thing I do," Osamu declared back.
With one last glare, the two fell asleep with their backs against each other.
In the morning they woke up tangled in each other's limbs but neither of them had enough pride to admit it.
~
As years passed, the three became best friends. They began keeping their room clean so Kiyoomi would feel comfortable spending the night.
And of course, the two fell more and more in love with Sakusa.
Suna Rintarou eventually joined their little pack in highschool and the group began to get weird. Suna and Sakusa would tense up when either of them got close and Osamu spent most of his time huddled in a pile of clothes in his bed.
Atsumu thought it was weird, why was everyone around him acting so odd?
He got his first reality check when Sakusa went into his first rut. The twins had no idea their crush was presenting until they walked into the Sakusa residence with sleeping bags.
Almost immediately, the stuff in their hands dropped to the floor and they froze in place. The scent was overpowering. It was the strongest thing they have ever smelled.
Things got weirder when Osamu let out a high-pitched whine and dropped to the floor clutching his stomach. Atsumu stood in fear before scooping his brother into his arms and charging to his house.
His mother jumped feet into the air when Atsumu burst into the kitchen with a crying Osamu in his arms.
"We need to go to the hospital! I think Osamu's dying, he's crying so much! Mom come on get the keys!" He screamed out in a single breath.
Their mother blinked at them before laughing over the brownies she was making.
Atsumu gasped in shock. How could their mother LAUGH when Osamu was dying!?
"W-Wait put him on the couch," she finally gasped out.
Atsumu grunted angrily and walked into the living room with his brother withering in his arms. Fear and anger clouded his brain, all he could focus on was his baby brother in pain.
When their mother appeared out of the kitchen, she sat him down.
"Atsumu, you're both 12 now and that means things are going to change. Your brother isn't dying, he's presenting as an omega. His body is growing organs in his stomach to prepare him for a baby. Sakusa's rut must have triggered his heat which means soon, the two will be possessed by certain instincts," she trailed off awkwardly.
Atsumu glanced over at his moaning brother, noticing his scent was becoming...a lot sweeter. Almost disgustingly sweet.
"Ah...we should get him to your guy's room. You'll need to sleep on the couch for about a week," she finished and stood up, ready to head back to the kitchen.
"Wait mom..." He hesitated, he almost didn't want to know.
His mother paused and turned around with a smile.
"...Why am I not presenting?" He asked.
She hummed and turned back to the kitchen, leaving him behind with a sentence that changed his life.
"You are dear. You're presenting as a beta."
~
At 17 Atsumu realized that it's expected for alpha's and omega's to get together in life. Actually, it is extremely frowned on if they mate with anything else.
That means Sakusa Kiyoomi could never be his. After his presentation, he bulked up and grew out, he became the strongest alpha he has ever seen.
Female and male omega's alike flocked to him now, all breathtakingly beautiful and eager to please him. Why would he ever look at boring, beta Atsumu?
His fears were answered when he and Suna rounded a corner in school and stumbled upon the scene of Sakusa pinning Osamu against the wall, tongues shoved deep into each other's throats. Osamu had his legs wrapped tightly around Sakusa's curvey waist and Kiyoomi gripped his twins hips with a brushing grip.
Atsumu let out a heartbroken gasp while Suna growled angrily at his side. He knew for a long time that Suna liked Osamu because of course he did. Who wouldn't love the beautiful, amazing omega?
The two in front of them broke apart in shock and turned to them. Osamu immediately met his eyes and popped his mouth open to say something.
Probably to rub it in his face that he won.
Atsumu didn't let him say anything. He turned on his heels and ran down the hall, leaving behind the angry snarls of two alpha's and Osamu pleading for him to wait.
He finally came to a stop at the park and huddled under the slide. The sky was a sickening gray, perfect for his mood.
Tears slid from his hazel eyes. He didn't feel it though. Everything was numb. His heart was broken and his head hurt.
Why was life so unfair? Why did he have to present as a beta while Osamu got to be a omega? He had admirers begging for his attention at his feet while Atsumu had...nothing.
Who loved him? Who would ever love him? Who would fall for Miya Atsumu? No one of course. He was annoying and loud and honestly, really ugly.
He hated himself more and more as the sky opened and rain poured down around him.
He didn't care. He didn't care about anything right now.
He scratched at his useless scent glands until his skin broke. Blood dripped down his neck from the wounds. This was the only time he'd ever feel blood on his gland. It's not like anyone would bite him anyways.
The muted sound of rain hitting the ground blocked him from his thoughts. He was grateful for that, he doesn't know how much longer he could be in his head.
He didn't realize someone was with him until hands gripped his shoulder and Osamu was in his face screaming.
Ah. Maybe it wasn't the rain that was muted. It was him. Osamu's voice drifted into one ear and out the other. Everything was too quiet or was it too loud? He didn't know, everything was numb.
The only thing that caught his attention was the strong smell of lavender and honey. Atsumu rolled his head to the side and met the deep abysses of Sakusa's eyes.
It hurt.
He didn't want to see him. He didn't want to see any of them. Osamu was gripping his bleeding neck with trembling hands. Suna was talking on the phone, face unnaturally scared.
All he could see was Sakusa. And then nothing at all. Atsumu blacked out to the terrified screaming of his brother.
Waking up in the hospital wasn't fun. Machines beeped too loud and the bed always smelled like chemicals.
Not to mention the people who cramped around his bed the second he opened his eyes.
His mother cried into his chest, blubbering incomprehensibly.
Osamu was standing off to the side with Suna and Sakusa.
"Ah...don't look so grim it's not like I'm dead," Atsumu croaked.
"Not funny 'Tsumu," Osamu sniffed.
Atsumu chose to ignore his brother for now, it really wasn't a good idea to throw down in a hospital.
"Come on ma. Stop cryin' I'm fine," he patted her back in comfort. He hated seeing his mother cry.
"You better be. What were ya doing at the park during a rain storm!?" She scolded, gripping his clothing tightly.
Oh. So nobody bothered to inform her about what happened. Just leave it up to Atsumu to take care of it all.
"Felt like swingin'" he replied instead. Like hell are they just going to throw the responsibility onto him.
"You idiot," She pinch his side angrily but giggles at his answer.
Atsumu managed to hold in his anger until she left for the cafeteria. Now it was just the four of them sitting in silence.
"...I think...we should talk," Osamu finally grunted, shifting uncomfortably.
"Don't wanna. All of ya should get out of my room. Except Suna, he's cool," Atsumu decided after a moment.
Suna hummed in response and flopped down across his legs.
"Ok ah...what you saw isn't what you think," Sakusa mumbled behind his mask.
"Oh so you weren't making out in the hallway," Suna deadpanned.
"...Maybe ya should let us speak," Osamu said.
"Maybe you should get out of room before I punch you in the face!" Atsumu grinned cheerfully, deciding a hospital fight sounded FUN right now.
"I'm about to go into rut. And he's about to go into heat. We were walking together when both of our instincts kicked in. All I knew was that a omega was close and I was really horny," Sakusa grunted quietly.
Oh God were they about to go into detail about their make out session.
Suna's expression mirrored his disgust, maybe he should just get with Suna, they seemed to be on the same wavelength.
Too bad he was in love with stupid Sakusa.
"I don't love Sakusa anymore 'Tsumu. I haven't...for a long time," Osamu whispered and blushed awkwardly.
"And I never loved Osamu. That was just our instincts getting the better of us," Sakusa added.
"So it's fine if you guys make out, as long as ya don't have feelings for each other? Will you shut that bullshit up you assholes," Atsumu hissed angrily.
"Dammit Atsumu I don't love him, I love Suna!" Osamu growled in annoyance.
The room went silent before Suna stood up and dragged Osamu out of the room. Most likely to talk alone.
Atsumu and Sakusa sat in the room alone, silence heavy between them.
"Sucks for you huh? Osamu has a crush on Suna," Atsumu finally snorted.
"Not really, I knew he liked him for years. I don't love Osamu," Sakusa shrugged.
"Oh really? Then who do ya love? Please inform this disgusting beta," He snapped, gripping his sheet tightly.
He didn't want to hear this. Oh man what if he's in love with Suna? Two alphas mating each other. If betas and alphas were frowned on, that was worse.
"You."
-Betas weren't allowed to be with anyone accept other beta's. Wait what-
"What?" He choked, heart squeezing in his chest.
"I love you. If you didn't notice, I have since we were children," Sakusa informed while playing with his fingers anxiously.
"...holy shit," he breathed.
"The reason why you fainted today...it's because you saw your soulmate with another person. I'm sorry I did that to you," Sakusa rasped, voice thick with emotions.
Soulmate? When did that happen?
"What?" Atsumu asked again.
"The doctor told us while you were asleep. I'm your soulmate," he said with more strength in his voice.
"... we're soulmates," Atsumu gasped.
Sakusa stood up and crouched over him, hands cupping Atsumu's face tenderly.
"We're soulmates. I'm sorry and I really, REALLY love you Miya Atsumu," Sakusa whispered above his lips.
His breath caught in his throat and his eyes burned with tears.
"Again," he sobbed.
"...I love you."
"Again."
"I love you."
"Again."
"Atsumu I love you."
Atsumu hiccuped and leaned closer.
"Then kiss me."
When their lips met, the world burned away. His skin heated up at the touch and tears poured from his closed eyes.
After they parted, Sakusa placed his forehead over Atsumu's.
"Spend my rut with me," Sakusa whispered, voice deep in his chest.
"Oh god yes."
Atsumu was 22 when he married the love of his life. After years of struggling, he stopped caring about what others thought. So he was a beta mated to an alpha. Bite him.
Suna married Osamu a year after and immediately began popping out small Osamu's. The two got over their argument and grew closer then ever.
In the privacy of Atsumu's living room, Osamu flopped down beside him on the couch and cuddled into his side.
"It looks like you won 'Tsumu."