Work Header

Mated For Life

Chapter Text

Chapter 1: Mistakes


Itner woke up in a room that wasn't his, and immediately cringed.

He remembered exactly what happened last night, and wished he didn't.

He and Katsuki had sex...

Even though he recalled last night ending in nothing but pleasure, he couldn't stand the alpha.
He was arrogant, loud, brash, annoying, and overall just an asshole. Itner looked behind him, the blonde still asleep, and he slowly got up, getting his clothes back on, and headed out. He looked around carefully, making sure no one saw him. he quickly dialed his best friends number.

"I-Itner? Do you know what ti-"
"-I know it's early, but I really need someone to talk to."
Izuku told him to come up to his room, which the omega did gratefully.
Itner slept next to the alpha for a few hours, after telling him what happened with Bakugou. When the woke up again, they talked some more.

"Do you really hate Kacchan?"
"Is that seriously a question?"
"I just think that you never gave him a chance because he hates me..."
"Why would I give him a chance? He's an asshole who needs to realize that the world doesn't revolve around him, he isn't the strongest person in the world, and that he's just a cocky asshole."
"-I'm telling the truth."

Izuku smiled, lightly punching the omega. "Want to go get breakfast?"
"Yeah, I'm starving."

They made their way to the kitchen in the dorm, and Itner said that he would make pancakes for the both of them. Izuku sat at the counter, talking to the omega, until he heard people coming downstairs. The omega noticed too, since he stopped talking as well. Coming down the stairs was Mina, Kirishima, Sero, Kaminari, and Bakugou...

The blonde alpha came over grumbling, getting a pan ready. Itner guessed he was making eggs for his friends.
Itner was happy that he came down earlier meaning that he was done with their food, so he and Izuku went to the table furthest away from the other group. He had also made food for Iida, Todoroki, Tsuyu, and Ochako.
"Don't make it awkward Itner."
"I'm not. I'm just thinking if he told them or not. Kirishima keeps glancing at me, and Mina and Kaminari are whispering..."
"Doesn't mean it's about you..."
Soon the rest of their friends came over, getting their food and thanking the small omega.
The omega told the rest of his friends what happened last night.
"Was it good?" Todoroki asked.
"Todoroki!" Ochako blushed.
Itner shrugged, "Yeah. It was amazing."

Itner got up and collected all of their plates, rolling his eyes because Katsuki was doing the same. He came up to the sink, washing the dished quietly, trying to ignore the blood red eyes glaring at him.
His friends were waiting for him to finish, so they could walk to class together. Bakugou's friends were doing the same.
"What?!" Itner hissed, tired of being stared at.
"You can't talk to me after we just fucked yesterday?"
"And say what? What do you want me to say?"
"Anything, don't just not talk to me-"
Itner finished his portion, looking at the tall alpha, completely aware that their individual group of friends were within earshot.
"I want my panties back."

Ignoring the way both groups were either laughing or blushing, he took in Bakugou's face. His mouth wide in shock.

Chapter Text

Chapter 2: Sickness


This was the third time today, with Izuku holding his hair, Itner was throwing up what he had ate for lunch.
"First it was breakfast, then from looking at Mineta, then your lunch. Wanna make it four times today?"
"Shut up you cheeky little shit, I've just been feeling like shit lately. That's all."
"Then go to Recovery Girl. Please? What if it's more serious?"
"After class today, I'll go...Go with me?" Itner said, looking up at his friend.
"Of course I will. Let's get changed in here, so we'll be ready when we go back." Izuku said, wiping Itner's face with a wet paper towel.
They quickly got into their costumes and made their way to Ground Beta.


Bakugou watched as the raven haired omega made his way to his friends, not wanting to admit that the omega looked amazing in his hero costume.
His costume was a skin tight body suit, with white trimming all around, with holsters for different types of weapons in them.
He looked good.
But he looked worried.
The omega was whispering to Aizawa, and then he stood with the teacher through the whole class. After class he hurriedly grabbed Deku's hand and ran with him.
What the hell was going on?


They both made it just in time before she left, and asked her to give Itner a check up.
"I've been feeling really sick the past couple of weeks, I keep throwing up, I can't keep anything down, and it keeps me up at night sometimes."
"Sounds like you've been having a bit of trouble. Why didn't you come sooner?"
"I didn't think much of it, Izuku wanted me to come to make sure it wasn't anything more serious."
She hummed, instructing him to unzip his costume and lay down.
She felt around his stomach, for longer than he wanted...
"Answer me truthfully...have you had sex in the past few months?"
"Y-yeah. But that can't be it...when an omega gets pregnant, doesn't the alpha know automatically? I think he would have said something."
"Not necessarily. Are you and the alpha mated?"
"N-no, but-"
"So he wouldn't have noticed, but he would have noticed your scent changing. Have you noticed the alpha acting strangely?"

He thought back to how Bakugou was acting after it happened?
Still yelling, cursing, and like an asshole.
"No, he was acting how he usually acts."
"But I do need to be sure. I have pregnancy tests in the bathroom."

Itner got up, slowly walking to the bathroom.
A pregnancy test.
A fucking pregnancy test?!
He knew what that meant.
And she already pretty much confirmed it.
Did Bakugou think he smelled different?
How about Aizawa? He's an omega who's been pregnant before, did he know?
What about older alpha's?
He could feel tears of frustration building in his eyes.

Might as well get it over with...


He gripped the test in his hand tightly, of course it was positive...
He breathed in deeply, trying to calm his nerves, but he couldn't and he was starting to cry.
He was pissed.
He had sex once, and looked what happened.

He had to talk to Bakugou.
He had to see what they were going to do...
He had to talk to him now.

Chapter Text

Chapter 3: Telling Him


Itner ran to Bakugou's room, cursing when he found out the alpha wasn't there.
He quickly grabbed his phone, calling the alpha's friend.
"Hey Itn-"
"Where's Bakugou?"
"...He's here in my room, we were just about to start training-"
"Wait! I need to talk to him!"

Itner didn't wait for Kirishima to finish, he was already running their way.
He saw the two alpha's and quickly grabbed the one he wanted to talk to.
"What the he-"
"I-I've been trying to figure out how to tell you, and I haven't been able to say anything because I'm about to panic, I need to see what we're about to do about this stupid bullshit-"
"What the hell are you talking about Itner?" Bakugou asked.
"I-I-I-I'm pregnant..."
Bakugou's eyes widened like saucers, mouth agape.
"I. am. pregnant. What is going to happen now?"
"What do you mean? Are we keeping it?"
"I-I don't know...we're young, and I'm trying to become a hero...are we ready for that? Plus, we aren't even together..."
They stood in silence, both taking in the information.
"I want the kid half pint, whether or not we hate each other should have nothing to do with the baby."
Itner looked up at the alpha, smiling, hands on his stomach.
"What do you think it'll be?"
"A boy for sure."
"Don't say that, I want a baby girl."
"It honestly doesn't matter shorty, as long as they're healthy."
Bakugou raised his hand, waiting for the omega to grab it, which he did.
"We're going to be the best parents in the world Itner."
"Y-yeah. You might as well tell the rest of your friends, Kirishima's crying."

Sure enough, the red haired alpha was crying. Wiping his tears, but still crying.
"Congratulations guys." Kirishima said, coming to hug the two.
"Thank you Kiri."
Bakugou huffed, "stupid nosey idiot....thanks."

Chapter Text

He wasn't used to this....
He knew that the omega hadn't been getting any sleep, and that he would come to class tired, exhausted even. He had a very short temper that erupted everytime the grape pervert opened his mouth.
They both went to Recovery Girl after the omega almost snapped his neck.
"He's restless, maybe because you both aren't actually mated and he isn't around you a lot. Just give him a piece of your clothing, he'll be fine."

Except, the omega didn't want his clothes....
"What? I'm restless? That sounds stupid, I'm going to be able to sleep by getting a shirt from him? Fucking idiots. I'll be in your room when you are ready to do the homework." He snapped, walking out of the door.
Recovery Girl sighed, "his hormone levels are changing, he'll be back to normal when he gets further along. He's going to have mood swings a lot so be prepared."

The blonde alpha walked to his room, and unlocked the door and rolled his eyes.
There on his bed, Itner was laying down, sleeping.
He was snuggled up in Katsuki's blankets, a look of relief on his face.
Katsuki was about to wake him up, but knew that Itner hadn't been getting any sleep at all, so he let him sleep.
The omega had a look of bliss on his face, and he slept for a full five hours.
When the omega did eventually start waking up, it was around 9pm.
"Damn... That was the best sleep I've had in a while."
"And you said you didn't even want to use my scent to fall asleep."
"Shut up-....but thank you for letting me sleep, I appreciate it."
"Sure, you need to do your homework, eat and drink some water before you go back to sleep."
"I'm not-”
" You are going to eat and drink some water. Let's go."
Itner rolled his eyes, but had a small smile on his face.
They made their way down stairs and the alpha made himself and the omega something to eat.
Itner ate slowly, but he did manage to eat most of it, and Katsuki finished the rest. He was forced to drink some water, and they made their way back upstairs.
Itner crept back into Katsuki's bed, sighing in happiness.
"Stealing my bed....stingy omega." Katsuki smirked.
"You'll be fine. We can share tonight if you're okay with it. Then I'll just take some of your clothes with your scent on it from now on."
The alpha turned the light off, and got into the bed facing away from the omega.
"You can cuddle me you know?"
"I'm already pregnant, what can happen now, plus, it's cold."
The alpha smiled lightly, pulling the small omega closer to him, knowing that Itner is always complaining that he is hot, or burning up.


When they woke up, they walked to class together, and the alpha allowed the omega to get pieces of his clothes, if he wasn't sleeping in his room that night.
Katsuki was currently missing eight shirts, four pairs of pants, his workout shirt, his uniform tie(that's why he doesn't wear one😁), and his favorite all might shirt.

Chapter Text

Chapter 5: Growth


Katsuki couldn't help but state at the omega, almost all the time.
Itner hadn't changed anything about his appearance, his hair was still long and straight, his eyes still a deep blue, freckled still on the bridge of his nose. But his uniform was slightly different, Itner had text him this morning saying that he needed a bigger uniform. Katsuki knew this day would come, with the omega being two months now, he was supposed to get bigger.

But actually seeing it, the actual baby was adorable, not that he would tell the omega that.
The betas and other omega's in class immediately started rubbing the omega's belly, and he couldn't help but feel proud.

The omega was glowing, he was never angry anymore. Always smiling.
And Katsuki preferred it this way.

Then Itner came up to him, beaming.
"Look the how much she's grown!"
The blonde alpha smirked down at the omega, "yeah he's growing alright."
Itner stuck his tongue out at Katsuki, but then grabbed the alpha's bigger hand and placed it on his stomach.
"Doesn't matter as long as they're healthy right?"

They wouldn't be able to find out until he was about four or five months, but they both didn't care, just had preferences.
Itner had wanted twins, a boy and a girl, Katsuki told him to quit acting crazy.
Katsuki wanted a boy because he always wanted a boy first. Itner wanted a girl just so he can dress her up...Katsuki groaned by how much pink the omega had wanted to buy already...but he had told the omega they can't buy anything until they confirm the sex. That didn't stop Itner from buying a few gender neutral onsies, (Katsuki did too).
He could help but rub at the growing stomach of the omega.
He couldn't wait.


They were happy.

Chapter Text

Chapter 6: Hugs


Itner started getting very clingy.
The omega never slept in his room anymore, always in Katsuki's.
He was always wanting to be cuddled, placing the alphas hand on his small growing stomach. The omega was craving attention, even though the alpha had no problem with giving him the attention, adding kisses and rubbing him all over until he was purring, it wasn't his character.
So he went to Recovery Girl.
"He's most likely proud about his body changing and wants you to see the changes."

And proud he was.
He couldn't help but smile brightly when the omega told him he could no longer fit his uniform shirt. He was beaming, smiling from ear to ear. He loved his small bump, and Katsuki loved it too.

Katsuki sighed, as he wrapped his arms around the omega. They were currently wrapping up training, and the omega didn't feel like letting him go.
"I'm being very clingy I know....but I really do like this."
He smiled, tightening his hold. "It's fine...I like it too."
"It must be fun making special moves, AP Shot looks awesome."
The alpha loved that praise from him.

He knew the omega missed using his quirk, and he knew that the omega already had ideas for his special moves too, and he couldn't wait to see Itner back in action.

Itner's quirk was Light. His hero name was Ormazd, he wanted to be known as the God of Light. He could manipulate light in anyway he wanted to. Defense, offense, he could do it all, and he was very good with his quirk. Katsuki couldn't wait to see what Itner came up with.

The next day he hugged the omega as he spun him around, kissing him all over his cheeks and face because he scored the highest on a test.
"K-Katsuki! Put me down!" Itner laughed, his cheeks rosy and his smile bright.
"Good work shorty. You'll be doing third year work in no time. You're gonna pass us up soon."
He was proud of what the omega was accomplishing.
He couldn't physically train, so he mentally trained, and it was paying off.

Big things were going to be happening to the omega, and he wanted to be there every step of the way.

Chapter Text

Chapter 7: Meeting The Parents....and Family


Katsuki and Itner sighed together.
"Let's just get it over with."

They had both agreed to visit their parents when school work wasn't as intense. They had told both sets of parents over the phone and had promised they would be over soon. So they started with Katsuki's parents and Itner was loving it.

He was loving the attention he was receiving from Mitsuki and Masaru. They scented him, rubbed his growing baby bump, and told him how beautiful he looked.
Katsuki looked annoyed, but had a small smile, until his alpha mother patted him roughly on the back.
"Congratulations brat! I can't wait until the baby is here. I think it's a girl."
"I think it's a girl too, so it must be true! Mothers know best!"
Masaru was still rubbing his stomach, noting how the omega was glowing. (His omega father wanted a girl too)
Of course they were scolded for having sex early, and without protection, but they were comforted with the way that they would have help, no matter what.
"Make sure to come by more often, I want to plan the baby shower."
Mitsuki and Itner talked about the baby shower a little bit more, gushing about the clothes they were going to get. And then they were off to Itner's parents house.

He knew that Itner had a big family.
He just didn't know how big....but holy shit.
There were so many people.
One omega mother, one alpha father. Six beta, five alpha children, and one omega child. 12 kids in total.
Itner was talking to his mom something, the younger siblings were running around, playing and laughing. Katsuki shook hands with the older siblings, and then Itner's father.
The number 3 hero, Rin Hatsumoto.
The bigger alpha shook Katsuki's hand.
"Although I'm the most happy about how this happened. Itner looks happy, the most happy I've ever seen him. Keep my only omega son happy."
Katsuki nodded, making the older alpha smile.

He had a warm feeling in his chest, looking at his omega and knowing that both families were happy and excited for them.
He was happy.
He wouldn't change this for anything else.

Chapter Text

Chapter 8: Weight


When Itner was approaching the end of his second month, he was constantly staring at himself in a mirror.
"Do I look weird?"
Katsuki looked up from his phone, watching as the omega looked at himself at all angles.
"What? You were just the most confident person ever. What happened?"
"Just my stomach was growing at the time, now....with cravings and everything else I'm getting bigger....everywhere."

It was true, the omega was gaining weight. And now he was insecure.
The omega had always been small, so of course it was bound to happen.
"You don't look weird, if anything it's pretty sexy-"
The alpha coughed into his elbow, choosing not to look at how the omega blushed bright red.
"T-thanks....I guess it's just gonna take time to get used to."

The beginning of the third month, they went to their first doctors appointment.
Recovery girl had agreed to check on the baby for the first time, but told them they would need to go to a professional from then on.

"Are you excited?"
"It is the first appointment, so I am pretty excited. We won't be able to see what it is will we?"
"There's a possibility, but typically that's not until the fourth month."
The nurse instructed him to raise his shirt, and lower his pants.
Katsuki couldn't help but stare at the bump, the bump that seemed to grow everyday.
Itner layed back on the table, and all three looked at the screen, (after Recovery Girl put the gel on his stomach).
She had to search for a few minutes, but she did eventually find the baby.
Katsuki and Itner stared at the screen.
Their baby...
And they had a strong heartbeat.
"You're baby is perfectly healthy if I can say so. I've never heard such a strong heartbeat this early."
She took pictures and gave them both copies.
"Congratulations you two."

Katsuki kept looking at the ultrasound picture all day, all week, he couldn't stop.
He wanted to know what the baby looked like.
Blonde hair like his? Or black like Itner? What their smile looked like, nose, lips, he was more curious than ever.

"Scoot the other way, you're about to burn us alive."
It was three in the morning, and now the omega was complaining that he was hot, he was just freezing an hour ago. Katsuki rubbed his tired eyes, glancing at the clock.
"I'm hot."
"You could have been in your own room."
"You don't want me here anymore?"
"I didn't say that-”
"...Get back over here, I'm freezing over here."
"You just said-"!
"I'm cold." Itner said, glancing at him.
The blonde alpha grabbed the omega, and started to cuddle the small male.
Itner hummed, curling his body taking all of Katsuki's warmth and cuddles.
(The alpha was in the mood to cuddle anyway.)

Chapter Text

Chapter 9: Holidays


By the time winter was rolling around, Itner had asked Katsuki to come with him to find a coat that will fit for the entire winter.
They had found one...but it sucked to buy a coat that wouldn't be fitting him for too long.
They went to class, the omega had sat with his friends that day, and he couldn't help but be a bit jealous...
Deku was an alpha, and also Itner's best friend, Half and half was an alpha, Iida was an alpha, Uraraka was an omega. He hung around too many alpha's.
He hadn't noticed he was close to growling until Itner shot him a confused look.
He rolled his eyes and looked away, they'd talk later.


They did indeed talk, the omega sat and listened as the alpha spilled his heart out. Itner had a shocked look on his face, he hadn't been expecting Katsuki to just out and say that he didn't like all the alpha's he hung around. But he couldn't just ditch his friends because the blonde was feeling insecure about himself at the moment.
"Wow...what happened to you. You were just talking about me being the most confident person but you ooze confidence. You're strong, smart, your handsome, talented, and a bunch of other stuff. Izuku and I have been friends since we were in kindergarten. Todoroki and I are just recently close. I don't think of them that way. There is absolutely nothing to worry about... Plus, the way your jealous right now is kind of hot...." Itner smiled, making the alpha laugh a bit, but still had his head down.
Itner sat on his lap, placing the alpha's hand on his belly.
"I only like you Katsuki. I've brought anyone over to my parents house for holidays. I....want to make this work. I really truly do." Itner was blushing harshly, looking away for a moment.
"It'll work out for us...I want this too."


During their break off from school, they went to Itner's family home first.
Everyone exchanged gifts, the younger siblings were begging to play tag with Katsuki until he eventually gave in. They sang holiday songs, ate a huge dinner, and he had to admit. He had the best time over there, he'd visit more often.
They stayed for the next few days, then spent actual Christmas over Katsuki's parents house.
Ate another huge dinner(Katsuki was going to have to exercise after but didn't regret anything), played board games, and they exchanged their gifts for each other there.
Katsuki had about three bags full of clothes, to replace the ones he wasn't going to get back, a pair of shoes, and the omega had bought him a new set of drumsticks, (that were the color of his hero costume.)
"Hurry up shorty, we don't have all night."
Katsuki had asked for Itner to come upstairs in his room to open his presents.
Itner had three boxes around him.
Katsuki told him what order to open them in.
"Big box first."
The omega ripped the wrapping paper off, and revealed that he had received some a teddy bear. A custom made one with Katsuki's hero costume on. The omega wouldn't let go for five minutes.
The second box was a necklace, with a matching pair of earrings and ring.
The third was a piece of paper.
"...look up?"
Itner shot his gaze to the alpha, who was above him. Holding a mistletoe.
Itner blushed.
"Ready for your gift?"
Itner felt his breathing stop when Katsuki's lips got close and swooped in for a deep kiss.
They kissed for about three minutes, holding on to each other, and going in for more.

Itner decided this way the best Christmas ever.