Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/8404630.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      M/M
  Fandom:
      Haikyuu!!
  Relationship:
      Yamagata_Hayato/Moniwa_Kaname
  Character:
      Yamagata_Hayato, Moniwa_Kaname
  Additional Tags:
      Alpha/Omega, Mating, Mating_Cycles/In_Heat, Mating_Bond, Mating_Rituals,
      Mating_Bites, Knotting, Fluff_and_Smut, Implied_Mpreg, Rare_Pairings
  Series:
      Part 12 of Mating_Night, Part 24 of Crack_ships_and_rare_ships
  Stats:
      Published: 2016-10-28 Words: 1868
****** Moniwa & Yamagata ******
by Bittodeath
Summary
     There is an old tradition in the lost villages of Haikyuu, to make
     sure there are no unmated young people: once every three years, at
     night, all the youth between sixteen and eighteen are gathered at the
     entry of the village, Omegas and Alphas alike. They presented as
     either Alpha or Omega and, under the watch of the leaders of the
     village, Omegas are sent into the forest, to run and hide themselves.
     A moment later, Alphas are sent after them. The first Omega an Alpha
     manages to grab is destined to become his mate, and they have to mark
     each other during the night and come back to the village once mated.
Notes
     I think that was the rarest pair of all. And it was a lot of fun to
     write, so thank you Youkai_Hime for your request! I hope you'll like
     it.
See the end of the work for more notes
There is an old tradition in the lost villages of Haikyuu, to make sure there
are no unmated young people: once every three years, at night, all the youth
between sixteen and eighteen are gathered at the entry of the village, Omegas
and Alphas alike. They presented as either Alpha or Omega and, under the watch
of the leaders of the village, Omegas are sent into the forest, to run and hide
themselves. A moment later, Alphas are sent after them. The first Omega an
Alpha manages to grab is destined to become his mate, and they have to mark
each other during the night and come back to the village once mated.
This technique is not perfect, but everyone is mated and since their other
senses are hindered, most Alphas rely on their sense of smell and end up
choosing the “best smelling” partner, who is biologically the most compatible.
Thus, blood lines are strong – and no one can complain that they were chosen or
rejected. “Mating Nights” are joyous occasions, often followed by a consequent
number of births.
 
Karasuno Village is a particularly remoted village, with only two women but
luckily just an even number of young Alphas and Omegas. And the “mating night”
as finally arrived, under the supervision of their leaders, Ukai and Takeda –
or, as they are called now that they are mated, Keishin and Ittetsu. They have
gathered all their young ones, eager, bored, excited or frightened.
“It is night. You may go.”
 
Yamagata didn’t really know what to do. Run, hide, just sit where he was and
wait? It seemed to him that all other Omegas knew what to do. He turned to see
Ushijima just walking around, looking around him. He was surprised that his
friend had turned out to be an Omega, but well, Nature was supposed to know
what she was doing so it was probably alright. He for sure didn’t mind being an
Omega, so long his Alpha wasn’t some asshole. Well, Karasuno’s Alphas were
nice, so he wasn’t too worried. He settled for sitting on a stump and wait for
the first Alpha who would claim him. Walking around now that the sun had set
seemed futile and stupid anyway, all he would get would be a fall nose first
against a tree. He distinctly heard Keishin’s starting cue, and well, it was
not his fault his heart was pounding a little faster, was it?
Moniwa was tense. Not like he didn’t trust his capacities, but he wasn’t very
out-spoken for an Alpha, so there was that. He sighed, watching with envy bulky
Alphas like Bokuto, or Tanaka. Omegas loved to feel protected and his lean
frame wasn’t exactly Alpha-like. That didn’t mean he wasn’t strong, on the
contrary. He knew better than anyone else what his body could do, and he never
doubted his ability to protect his mate and make them feel safe.
But then again, guys like Hinata and Nishinoya were Alphas as well and they
were smaller than Omegas. He bit his lips, hating to admit it reassured him. He
would be fine, there was no reason things would go wrong. He felt everyone
tense when Keishin walked in front of them, the ghost of a smile on his lips.
Unconsciously, he prepared himself to race to the forest where Omegas were
hiding, teeth bared in a snarl – he would claim and take and… What the hell?!
He reeled back at his own instinctive thoughts, staggering.
“Careful!” a gentle voice said, arms wrapping around him to help him steady.
“Thank you”, he said, pulling away and turning to nod at the Alpha, “Sugawara.”
The silver-haired Alpha nodded with a smile, taking back his position.
“It is night. You may go”, Keishin said, and suddenly Moniwa found himself
racing with the others, slowing down and fully stopping once he was alone in
the scents-filled forest. He took the time to catch his breath and analyse the
scents, though one of them immediately hit him like an evidence. Though he kept
searching just for his own conscience, he knew he had already taken a decision,
his feet moving automatically towards the Omega. As the scent grew stronger, he
realized he was probably nearby and reached inside one of his pockets for
matches. He lit one and there was definitely someone sitting on a stump in
front of him.
He walked closer and the Omega stood up, brushing his jeans – a strange choice
of clothing for Mating Night, but Moniwa had to admit it looked good on him.
“Have you come to claim me, Moniwa?” the Omega simply asked, and the Alpha
gulped, nodding.
“Indeed, Yamagata.”
Yamagata flashed him a blinding smile and closed the distance between them,
standing… well, too close for comfort. Moniwa felt himself blush – the Omega
smelled really, really good, and he was really beautiful. The match chose this
precise moment to give up and they found themselves in the dark. Moniwa reached
for another, his hands accidentally bumping against Yamagata’s chest and he
swore the Omega huffed a laugh. His hands were trembling nervously, his mouth
dry and his face heating up.
“Let me”, Yamagata said, seizing his hands and lighting a match immediately.
He was even closer than before, his eyes gleaming, and suddenly Moniwa’s
fingers were in his hair, gently rubbing against the shaved part, and to his
surprise Yamagata purred, slouching towards him as if asking for more. Grabbing
his face and kissing him only seemed natural, Yamagata’s arms wrapping around
his waist as he slowly deepened the kiss.
“Kaname”, Yamagata breathed slowly, and Moniwa was glad his Omega was just
slightly smaller than him.
“Hayato”, he murmured against his lips, kissing him once more, his fingers
tightening in his hair, and damn was that his own voice?
He could definitely feel Yamagata trembling against him, probably just as
nervous as he was. His hand slipped to the Omega’s fingers, squeezing tightly.
They lit a third match and Moniwa guided him to the closest unoccupied nest.
Nests were ovoid constructions made of branches, looking a bit like giant
cocoons and filled with leaves, wool and feathers. There were one or two
blankets as well, and the whole seemed really comfortable. They climbed in and
Moniwa grabbed the small wooden cage filled with ladybugs meant to give light.
Yamagata immediately crawled closer, sitting in his lap and hugging him
tightly, nuzzling his scent glands, eliciting a comforting scent. The Omega’s
warmth felt good against him as he soothingly rubbed his back – he could feel
discomfort in his mate-to-be, though he couldn’t pin-point it.
“What’s wrong?” he murmured in his ear, and Yamagata shivered.
“I don’t know”, he mumbled against his skin, “but I feel better when you’re
close.”
Moniwa didn’t remember taking off Yamagata’s clothes, nor the Omega shedding
his clothes, but the facts were there: he had a very naked, very flushed, very
beautiful and very attractive Omega in his lap, and his fingers were definitely
spreading slick on his skin. His mind felt foggy, entranced by Yamagata’s
parted lips, and his light panting. Yamagata had his arms wrapped around his
neck, his hips shifting when Moniwa’s finger slid inside of him effortlessly.
“F-Fuck”, the Omega muttered in his ear, “I know what’s happening.”
Moniwa couldn’t help but chuckle, his mind hazy, unable to focus on anything
else than the Omega writhing against him as he fingered him gently.
“Well I am pretty sure that’s what’s called mating”, he answered, nibbling on
his earlobe.
Yamagata scowled, swatting the arm wrapped around his waist, and shifted closer
to rest against Moniwa’s crotch. The Alpha let out a strangled moan, taking a
shaky breath and nipping as his jaw.
“Kaname”, Yamagata murmured, “I’m going into heat.”
Moniwa would have jerked back in surprise if his mind hadn’t subconsciously
absorbed the information already. Instead, a loud groan escaped his lips,
instinctively pushing back against his Omega. Yamagata cried out in surprised
when he found himself on his back, Moniwa weighing between his parted legs and
against his chest as he kissed him passionately.
“Mine”, Moniwa snarled against his throat, his hands pulling away from him to
take off his clothes, “Hayato.”
Yamagata shuddered at his Alpha’s tone, possessive and borderline aggressive,
and he’d never thought his Alpha would be this possessive over him and the
simple thought sent warmth coursing through his veins. He wanted this, and his
body craved this possession, arching under Moniwa’s fingers, his hips lifting
to slid against him. He cried out once more when his heat settled in, stronger
than it had ever been – he couldn’t really remember a moment when he’d totally
lose control during his heats, but here he was, his mind blank as instinct took
over.
That was the moment when Moniwa snapped, entering him in one thrust that seemed
to set both of them on fire, the rabid roll of his hips quickly sending
Yamagata over the edge. However, the Alpha didn’t stop, and soon he was biting
his throat, claiming him, marking him, his Omega crying out in pleasure as
another orgasm ripped through him, their bodies locking together when Moniwa
finally came, his fingers gripping Yamagata’s hips so tightly it was going to
bruise. Yamagata closed his jaws on Moniwa, breaking through the skin and
sealing the bond.
They were panting heavily, and Moniwa wrapped his arms around his mate, staring
into his eyes. Yamagata smiled softly, burying his face in his neck.
“Thank you”, he murmured, his voice hoarse.
Moniwa breathed in the scent of his hair, pulling the covers up their bodies.
Their bodies fitted nicely together, the Omega soon falling asleep in his arms.
Yamagata woke up in the middle of the night when another wave hit him, shaking
Moniwa awake for another round as the almost painful warmth settled in. Both of
them were totally exhausted when they got back to sleep.
Moniwa woke up first, late on the following morning, immediately pulling
Yamagata closer, a contented sigh leaving his lips as he did so. Protect, his
instinct told him, his hands automatically settling under Yamagata’s navel.
“Mine”, he murmured sleepily, taking in the sweet scent of his mate – sweeter
and softer than the previous day, more fragile, intimating him to protect him –
them. His eyes snapped open at the realization and he jolted awake, unwillingly
shaking his Omega. “Oh my god”, he said loudly, his voice shocked, his fingers
threading through Yamagata’s hair.
The Omega grunted, moving slightly to look at him as he opened his eyes. Then,
slowly, his eyes widened and he sprung up, his fingers trembling as he prodded
at his belly – it was still the same and yet he already felt different.
“I-I-”, he stammered, and Moniwa pulled him into his embrace.
“It’s gonna be alright, Hayato”, he murmured soothingly. “You’re safe with me.”
Yamagata smiled and rested his head against his shoulder, Moniwa’s arms draped
over the small of his back, their legs tangled.
“I was just shocked”, Yamagata answered. “But being with you like this… Knowing
it’s your child inside of me… It feels… right.”
Moniwa squeezed him a little tighter. Because Nature knew perfectly what they
needed.
End Notes
     Thank y'all for reading, as usual don't hesitate to comment either
     here or on my tumblr bittodeath.tumblr.com, or ask for pairings that
     haven't been done yet.
     You know what's gonna be funny? The "two years later" part. I can't
     wait to write it!
Please drop_by_the_archive_and_comment to let the author know if you enjoyed
their work!