Alright! So i threw in some science- made up science anyways lol

I think this is a very large chapter... It felt like it took forever to edit LMAO

Izuku gets to find out what type of undetermined he is ! How exciting and nerve-wracking lol

It was about Tuesday morning when Dabi woke up from his hazy heat to see he was asleep beside of Izuku who was fully clothed. He was also unaware that refused to go back to his own room with Shouto watching him. He was painfully aware nothing happened and honestly it was a damn shame. Izuku was a sweet guy and he was just downright polite- too much for his own good.

Dabi stood up and groaned as his body popped in places several times.

He went into Izuku's bathroom and started a shower. His legs and ass cheeks were covered in slick that was either drying or still wet. He wasn't intersex like Tomura so it was a little different. Most alphas preferred the intersex omega males than the ones with just assholes. It was disappointing really.

He showered as quickly as possible but to his surprise, Izuku was standing at the bathroom doorway with his clothes. The guy offered him a big smile. For a moment, Dabi was suddenly shy he was naked. He turned a little pink but ignored the embarrassment. He took the pink towel from Izuku.

"Um…. did anything happen between us?"

Izuku blinked rapidly before giving a small smile.

"No but not for the lack of trying. I'm just glad you're ok."

Dabi smiled.

"So…. your mark is fading."

Izuku reached up and touched his scent gland. His eyes looked a little pained.

"Y-yea for the time being."

He turned to leave the bathroom but Dabi grabbed his hand.

"Why him and not me?"

Izuku looked guilty so suddenly.

"I just can't explain it. Dabi, you are a gorgeous omega and quite attractive but I don't know. I've been lost on scents and how things work for everyone else. I wish I could answer. It's just him. Maybe my undetermined side knows more than I do."

"They say you know you found the one when they smell sweeter. That's what my mom told me anyways. Tomura smells like toasted marshmallows…. like a campfire in the autumn. I like it."

Dabi grinned, "He definitely doesn't smell like that to me. He smells like a suffocating heat wave, especially when he's mad."

Izuku grinned.

"I guess I don't smell that? I wish I could smell the scents like all of you do. I feel like I'm missing out."

"I feel like I'm missing out. I was hoping to be mated by nineteen, twenty the latest. Now I'm twenty two. I just feel old as fuck."

It felt like that since society deemed it that way. Once an omega hit twenty, their 'worth' started dropping.

"Do you have a preference in mate?" Izuku asked.

"Um not really? I figured I could even settle down with another omega if I wanted."

"I have a friend. He is alpha."

Dabi tilted his head to the side.

"Are you trying to set me up?"

"Maybe, if you're ok with it. I can give him a call. I think you two would be good together. He's really nice."

The omega looked thoughtful for a moment.

"Did you already ask him?"

"Nope. I wanted to ask you first."

"I am old for an omega…. Usually we mate really early. Would he be ok with that?"

Izuku rolled his eyes, "He's twenty one. I started college earlier than most so he a few years older than me. Society says you're 'old' but you really aren't."

The omega smirked.

"Set me up for Friday. I wouldn't mind."

"Alright."

Dabi got dressed and helped Izuku change his bed sheets. This poor guy had done laundry so many times since he moved in and never complained once. Dabi seemed to be in a lot better mood than usual thanks to Izuku. He was glad to lift the omega's spirits.

Izuku wouldn't have minded dating Dabi but Tomura made the move first and Izuku was just attracted to him first without realizing it.

"Lover boy is probably waiting for you."

He snorted, "We kind of made up."

"I'm sorry about hitting him in the eye. I was so pissed he was acting like a douche."

"O-oh. Well…. I don't… ok."

The black haired omega laughed but it cut short when Izuku's phone rang. No one really called him so it was kind of a shock.

"Oh it's Dad."

He pressed the green button.

"Yea Dad? Is everything ok?"

"My friend said she can meet with us in an hour and she can have your results about seven. Are you ok with that?"

Izuku's goofy grin fell quick.

"So…. soon?"

"No reason to be nervous. I'm on my way. Let's get some lunch."

"Oh ok. Bye."

"Bye."

Izuku hung up. He stared at his phone as his crippling anxiety started to set in.

"Are you ok?" Dabi asked as he placed his hand on his arm.

"I'm getting a genetic test done."

Now the omega looked concerned.

"Are you worried? What could be the worst of it?"

"I just…. I guess I've just been undetermined but this would cement what is wrong with me and I'm not ready."

"There was never anything wrong with you."

Izuku looked at him. Shouta had told him what happened because it all had been hazy for him. It was as if parts of his memory was missing and there was fog on the windows to say when he tried to recall it. He was devastated when the alpha told him what happened. He was glad to protect everyone but...

"An alpha broke into the house while you were in heat. He attempted to rape Tomura and I came close to killing him. Shouta told me what I did exactly and I don't even remember. He said I reeked of alpha."

The color drained from Dabi's face.

"Someone broke in?" he hissed.

"Shouto was protecting you and then gave Shouta your gun. Shouto had to take Ochako and Tomura to an omega hotel while I stayed with you. I don't…. I'm scared."

"You don't remember?"

Izuku shook his head hesitantly.

"Were you feral?"

Izuku had researched feral and apparently alphas can experience it when their mates are attacked or someone they're attracted too. Some people assumed it was thanks to a rut but it wasn't for those reasons. Feral was an overdrive reaction of the ability to self preserve like omegas experienced when it came to their kids. Feral omegas were common than feral alphas.

"He said yes."

"That's hot."

Izuku turned bright red as he turned on the washer.

"I got the rest of this. I'll take care Tomura for you."

"Thanks."

Izuku headed to his room, changed quickly and went outside to wait on his dad.

X

Tomura sat in his room beside of a box of pizza in his bed. He had been eating nervously on and off. Izuku continued to care for his best friend while he hated it so much but how could he be so mad? He was jealous and it was petty as fuck. He wanted Izuku all for himself and it was disgusting he felt that way.

He went to start a new round on his Mortal Kombat game with a slice of pizza hanging out of his mouth when his bedroom door swung open. Dabi stood there with a six pack of Code Red Mountain Dew.

"I came to apologize."

Tomura put his controller down.

"For what?"

"Taking up time with your man. I know how crappy that was of me."

He sighed, "It's ok. I know how he is and that's why everyone likes him. He would be great for anyone. I was being stupid and it took me some time to think about it. I deserved that punch."

Dabi smiled.

"Well, Izuku went off to do genetic testing now. Also I was informed my house was broken into and that you were assaulted. I also wanted to ask you if you are ok. That had to be traumatic."

"I….. Yea? I guess seeing Izuku feral was more powerful than some idiot breaking into our house. I feel better knowing I had someone to rely on for once. It was terrifying though. The way his eyes looked red was a whole other thing. The attempted assault on my body almost pales in comparison."

Dabi wasn't shocked by his response. Tomura wasn't the type to dwell on things no matter how bad they got.

"So, how was the sex?"

Tomura's face turned bright red.

"Um….. It was the best I ever had."

Dabi sat down on the other side of Tomura's pizza box. He pulled of a bottle of pop and handed it to him.

"How so? What was different?"

Tomura opened the bottle of liquid that was the same color as his face.

"I…. He let me do him."

The black haired omega choked on his drink.

"WHAT?!"

"It was great. It was nice. It just felt so good and it was nice he trusted me. It wasn't all one sided like how it usually is."

"I honestly have to say that is the dirtiest thing I ever heard! I've never done that!"

Tomura felt hot all over.

"Oh my god! I am jealous!"

The omega laughed, "It was very hot. Very sexy. Well, until I bit him against his will that is."

Dabi nudged him with him elbow.

"Very lucky."

Tomura smiled.

Maybe I am.

X

X

Izuku didn't want to get out of the car. His dad pulled him, rubbing his back trying to get him to relax.

"Come on. Don't worry about it. You wanted some answers and I'm giving it to you. She is very nice and she does this kind of thing for a living. I paid extra. She's very good at what she does. She does research for those of us who are different. She's not well liked but her medical opinion is taken seriously. She's the one who allowed me to get a hysterectomy."

He suddenly relaxed.

"I didn't want to become a lab rat."

The old man nodded, "I understand that. Let's get to it."

The building was small and looked a little old but the inside looked brand new. It was hard to see the inside since the few windows the building had were heavily tinted. The place was in shades of blue and the chairs were purple. It was calming in some way.

"Chiyo!"

An older woman came out of a light blue door. Her silver hair was in a tight bun and she looked annoyed until she saw Toshinori.

"Welcome! I have our lunch in the back. I have the place closed for the day."

"Oh I didn't want to be an inconvenience….." Izuku said loudly.

"Honey, you're not. I do this for certain people. My other business drops their paper work and samples in the drop box in the back of the building, I'm always working but this situation is special."

Izuku glanced at his dad who only smiled.

"Ok."

They followed her into her lunch room. She had food spread out but it looked like all vegetables. Izuku didn't have a problem with that but it was strange since he didn't meet many vegetarians.

"I have some cheese sticks in the fridge. There are some nuts on the fridge if you desire some protein."

"Thanks."

The three of them ate in silence. Izuku expected to be questioned but there was no questions during their lunch. Izuku had to admit all the food she had made was delicious. He knew vegans got slammed a lot but all this food was simple and damn good. He would have to ask her about it so he could make some at home for everyone.

Toshinori grabbed up the empty dirty dishes and started washing everything in the sink.

"If you don't mind honey, I need to ask some questions. Feel free to deny any if you're uncomfortable. This is just genetics. Anything you have experienced that seemed unusual for yourself or anything other people had noticed they have mentioned. Toshi said some stuff already. Sometimes living situations contribute to the genetics and changes in personality as well."

"Oh, um ok."

"Let's go out here. Thank you Toshi."

"Anytime!"

The two of them left the small lunch room. She led him to a room that was in shocking shades of yellow.

"I paint my room and design them to help the people that come in here. The kids that come in as well love the colors. I always show them each one."

"That's awesome."

"Sit here. I will draw six vials of blood and then question you but I think I already know what your genetic condition is. Don't fret my dear."

"Oh ok."

She can already tell?!

Chiyo grabbed the six vials and put on yellow gloves with pink polka dots. Everything about this woman seemed so bright. Izuku liked it a lot. She knew what she was doing as she stuck the needle into his arm, drawing out blood without it hurting. He had white coat induced anxiety from all the stuff they used to do him as a child every six months.

She finished in under two minutes and started grabbing tools he knew nothing about. He didn't want to annoy her with questions so he stayed quiet while divided up the blood in different machines. He really liked her. It was shame he couldn't go to her for all those stupid appointments he had a few times a year for his condition.

"Alright. So that's everything. This test is called the A-B-O. It tests for your second gender genes and including any other genetic defects. A lot of parents do come through here to get tested before they have children or get mated."

"Oh."

"So. What are your parents?"

"Alpha female, omega dad."

Chiyo looked surprised, "That is uncommon in itself. Alpha regardless of gender determines the second gender. BUT the male determines the first gender. If there are two males, they usually produce bigger males regardless of second gender."

"I didn't know that. I know female alphas usually like female omegas or betas but not usually other female alphas."

She smiled, "That is correct. Seventy six percent of female couples produce female offspring who are smaller and usually omega but that doesn't mean much to the individual."

Izuku nodded in agreement.

"Parents alive?"

"Mom is…. I don't know about Dad."

"Ok."

"Personality?"

"Mom is a traditional alpha and raised me to be alpha but I wasn't. Dad was more caring but they didn't get along. My dad won a lot of money but no one told me the exact reason why. Mom claimed he skipped town to another country but he made sure Mom and I were set up."

Chiyo looked conflicted.

"That is harsh. No siblings?"

"No…. Dad's pregnancy was hard and I had heard Mom was upset but never pushed it."

"Producing one child is usually against what alphas and especially omegas instincts. It seems like Dad dealt with a ton of shit. Omegas get a lot of mixed feelings but they are usually prized."

"Yea."

"Are you mated?" she asked.

He shifted in his seat.

"Is that a no?"

"He bit me but Dad- Toshinori gave me a shot to heal it faster. I know it's usually for rape victims but it wasn't like that."

Chiyo smiled, "Ah. What kind of omega is he?"

"He's not like a usual omega. None of them are in the house."

"You live with three, one alpha and one beta."

"Yes."

"How is he not usual?" she asked scribbling on her paper.

"They describe omegas as nurturing. Caring. He seems stunted on the caring part. He kind of explained he didn't have the greatest up bringing but he was treated better. Like in the way he described second gender wasn't everything. He loves pizza and cooking isn't a strong skill on his part."

"He sounds more alpha than omega. I bet he has great fertility."

"Y-yea. How did you know?"

"Let me guess…. He doesn't smell sweet to others but he sure does to you."

Izuku's face turned bright red.

"Do you know him?!"

She laughed, "Nope. Let me show you something."

She flipped to a blank page. It read:

A-X B-X O-X

"We all start off as this in the womb until the age of five. Over time, We get a second X on either the A, B or O. I have noticed in those who are omega but don't have regular omega instincts, come off like this….."

She scribbled again and showed him the paper.

A-X^ B-X O-XX

"They get both X's on the omega trait and one and a half of the A. Three percent of the omega population is like this. One percent has double O and one and a half of the B. There are some omegas with a missing X on the B and triple on the O…. that makes twenty percent. Then what Toshi is…."

She scribbled again.

A-^ B-X^ O-XX

"This renders him infertile and affects six percent of the population of omegas. They either miss the uterus or ovaries. It affects males more than females since a long time ago women only bore the children. The omegas with defects like that come to me to get help so they don't have to bare through a heat anymore."

"What are you?" he asked.

She smiled.

"I am considered undetermined myself. I cannot reproduce."

She scribbled again.

A- B-XX^ O-X

"By this genetic sequence, I am beta but they consider me undetermined because there is no A gene."

"Oh wow."

"The reason undetermines can't breed with each other is because it would produce undetermined children. They did some studies over the last one hundred years and it was 100% all undetermined children. No matter how many they had. No matter if any of them were intersex or just one gender…. This is sad to say but undetermined children mean normal people like a long time ago. All the children produced were missing all A, B and O. The government doesn't want that."

Izuku's head was reeling with the info.

"I trust you because Toshi does. You are welcome to tell your mate but no one else can know. That is strict info. It's why I got into this job."

"What happens if two undetermines get together?"

"Legally, the government cannot do anything. If they are mated, it is against the law to tear them apart. Undetermined can produce today's 'normal' children with only a one percent chance of producing an undetermined child with an alpha, omega or beta."

Izuku stayed quiet.

"The population is 40% alpha, 30% beta, 29% omega and one percent other. That other is us."

He nodded.

"Sorry! I love hearing you talk science but I finished the dishes."

Izuku pulled out his phone when Chiyo turned around to look at the blonde omega. He had been talking to her for almost two hours.

Wow. She's really interesting. Maybe I got in the wrong line of business.

"I wish I had gotten into the genetics instead," Izuku said looking at them.

Toshinori laughed, "See I told you!"

The old woman smiled.

"You certainly did. We have a few more hours until your results show up. Some tests should be done in an hour but I won't tell you anything until it's all done. Why don't you go out and buy some stuff for your omega?"

Izuku looked at his dad who nodded with a smile.

"If you go anywhere for coffee, can you pick me up four large cups? I refuse to buy another coffee maker. It is brand new and the company has refused to get me another one even after I tried returning it to the store."

"You haven't changed much."

Chiyo rolled her eyes.

"I need two shots thrown in there each please. Stupid machine."

The two men left the building and she locked it behind them.

"Do you feel a little better?" Toshinori asked.

"No."

They got into the car.

"I feel even more oppressed than before."

Toshinori placed a hand on his shoulder.

"Son, that will never go away in this day and age."

"I know."

It was true. Omegas who were outside of the norm were going to be treated like crap, like Toshinori. He still was unmated because no one wanted someone who couldn't produce children. That's what was beaten into their heads when they were young.

The trip to the omega store brighten his mood a little bit.

He ended up finding outrageously expensive blankets that had generic game controllers on it. He grabbed one of those and they had a blanket with pizzas and burgers on it. He grabbed those then found one that had a cake and little cake slices for Ochako. Apparently the place was more high end than the ones in town.

"Hey, I know Shouta is alpha but he loves cats. Get him this."

The blanket was black with white cats and pink paw prints.

"I love that."

"Shouto and Dabi are left, right?"

"Shouto loves the weather. Dabi likes working out."

"Oh ok."

Toshinori started digging through the racks.

"You think Eijirou would date Dabi?" Izuku asked.

The older omega stopped and stared at him.

"Why do you ask that?"

"Well, they both love working out. Eijirou loves eating and Dabi seems to like cooking."

"I guess that's a good start."

Izuku smiled, "I know it sounds stupid but Eijirou always said he was on the fence about kids. He loved the college dorms. A big ass house with several people living in it would work for him."

"I think that is a good idea. What made you start this match making service?" he teased.

"Everyone….. keeps saying I should be with Dabi. He smells wonderful and we cook well together but I don't feel the same way. I told him so but he seems eager with meeting Eijirou."

"That is nice of you."

"Thanks…."

"It must be hard."

Izuku looked up at him, "What do you mean?"

"To like someone who is unsure of you but having multiple people liking you at once. You don't wanna settle for less than what you want."

"You've been there?"

Toshinori nodded.

"I um…. liked an alpha woman. She was beautiful. Blonde, american. The night we were supposed to mate, she never showed up. She went into a rut a few days sooner and her parents didn't like me. They sprayed omega pheromones on some poor female omega and shoved her into her apartment. The alpha rutted pretty heavy…. she was one of those special alphas with a triple X on the A gene. So…. she would be in no control over herself and we rode a few out. She was gone mentally but she trusted me."

Izuku looked horrified.

"They had broke into my place, used one of my nesting materials and had a bottle made so the poor omega smelled like me and my alpha would take her. When she found out what had been done, she killed herself. I wasn't allowed at her funeral and it was blamed on me. I was angry at the world and I never found anyone after that. No one would match up to her in my eyes. She didn't care I was broken…. I decided to just teach and do that forever. I visit her grave every year on her birthday."

Tears were streaming down Izuku's freckled cheeks.

"I had several people who liked me but none of them were her."

"Dad….."

He placed a hand in his messy hair and messed it up more.

"I'm ok now. I really loved her. She smelled sweeter than a candy store. No one else could compare to that scent of sunshine, rainy days and lemon."

Izuku rubbed his nose on his shirt trying to get control of his emotions.

"Oh, um…. I found a cloud one."

He held it up to reveal a gray blanket with white, gray and black clouds."

"I-I like it."

The omega smiled.

"I'm glad."

They searched the whole store to find a yellow blanket with eggs and bacon on it. It was the only thing close to what Dabi would like and none had pictures of weights on them. Izuku paid the seven hundred dollars and fifty eight cents and they headed for a grocery store.

"I wanna get her a coffee maker," Izuku said.

"She'll probably slap you."

"That's ok."

Toshinori laughed.

Izuku threw in the best coffee maker model that made lattes as well. They found every single coffee flavor availabile and bought three boxes of espresso shots for Chiyo. He even topped off the basket with several different colored coffee cups. They returned to Chiyo's office later, hauling everything in.

She did try to slap them both and threw a box of coffee K cups at them but she was touched.

"I cannot believe you two," she said as she pulled out her coffee maker, "You guys want some?"

They both nodded.

She cleaned it fast and got it started. She turned to Izuku.

"I almost have all the info complied."

He nodded.

Oh god. What am I?

She poured out their coffee some time later, leaving it black and returned back to her work station. Toshirnori and Izuku stayed quiet. The both of them scrolled through their phones just to kill time. No one had messaged Izuku but he was glad. He was anxious already- he didn't need anyone asking questions. He was in the middle of reading work emails when Chiyo returned.

"Are you two ready?"

Izuku stood up so quickly, he knocked his chair over.

"S-sorry!"

He picked it up quickly and followed her. Toshinori trailed behind him looking equally as nervous.

"I was a little surprised by the result. I had expected you to be equal on A and O with double X's but you weren't."

"O-oh."

"Out of the undetermined people, the majority are A, B and O- all one X. A small amount are missing X's like me. Then there's .5% percent who are missing all X's like I had explained earlier. You are the third person I have tested to be different. All other genetics are clean."

She flipped the paper over.

A-XX B-XX O-XX

"You are perfect."

Izuku stared at her.

"You are all three second genders. You have the ability to produce alpha, omega and beta hormones. Those with A-XX and O-XX are rare but not as rare as you. You can't get pregnant but you can respond to situations as your needs fit. You are perfect. The reason you are so desired is when you're calm, your scent is neutral mix of all three. You can become feral, you're stronger and you have the ability to produce strong children. You are rare and the other two I have tested were just like you. They had multiple mates. Only one of you three was intersex…. Able to impregnate and get pregnant."

She went around the room, grabbing things and throwing them in the metal trash can. She threw the papers in the trash as well and lit a match. Izuku was flabbergasted.

"The government cannot know your type exists. I will fudge any papers to say you were double A, double O and half X of beta. That is a more common type of undetermined but it would explain why you don't rut or go into heat."

Izuku nodded silently.

Holy shit.

hitokori midnight: I'm glad I fixed your boredom lol for a short bit anyways :) you flatter me too much! thank you! I was a little worried about doing ABO. Most of them are downright dirty (no issue with that lol) but I wanted a little more and wasn't sure if would appeal to everyone. I do write for myself but it's fun to entertain others.

I read harry potter and just watched the movies last year in sept-oct actually with a friend. I read the goblet of fire back in 6th grade (I'm 32 now so it's been a long time) I actually shipped ginny and harry a lot when she popped into the story and started showing interest in harry. BUT I didn't like it in the movies? If that makes sense. I was blown away by hermonie and ron being together lol I liked it. If I had to pick a crack ship it would be malfoy and hermonie just because of all the obvious reasons LMAO I'm a huge shipper of villain/heroes regardless of their genders. malfoy wasn't an actual villain by the end but he's kind of a dick lol