Nagisa pov
In today's society we are distributed by our DNA status.
The Alpha, the strongest rulers who claim everything.

The Beta, who fill most of society

Then the Omega, the rarest and prize winners for Alpha.

Every month an Omega goes into heat and releases a sweet scent, pheromones, that will cause Alpha to start rutting.
If an Omega is rapped by an Alpha it is not punishable by law.
One would say it is the Omega at fault for releasing their pheromones to trigger the Alphas to rut.

Omegas are expected to play the wifes role, they were basically an object to Alpha. They have no say in the relationship and have to obey every command of the Alpha.
If the Alpha wanted to leave the Omega in a relationship, they were allowed to do so.

Even though Omegas are rare, male Omegas are the rarest of them all.
Because of the DNA the Omega possessed, it was possible for even the male Omegas to become pregnant.
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The day I turned 18 I went to the doctor to found out which class I belonged to.
However, to my surprise I was an Omega

Since my best friend and crush, Karma, was 1 year younger he still wasn't labeled as an Alpha.
For his case since both his parents were Alpha, it was 100% set in stone that he would also be an Alpha.

I didn't want to disappoint Karma or have him view me as some object...so I lied to him and everyone else.
I told them I was a Beta

Thanks to the suppressants my doctor provided me, my scent was covered and I no longer had my heats.
Although he told me not to take the drug often since it wasn't completely safe, I still continued to take it.
I lied to myself and continued to live as the person I wasn't.
I hate that I was an Omega, I felt like a failure as a man and a failure to Karma.

I still remember when we were younger, Karma vowed that we would be mates in the future...but...times change and people change.
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I wish we never had to grow up...we wouldn't have to worry about becoming an adult and fitting in today's society.

In the morning when I woke up I felt incredibly weak and felt like being held by Karma....being touched by him...by someone.
My heat was starting
"*huff *huff *huff" I panted
'Has it been a mongh already!?'
I held my stomach in pain as I had my other hand on the wall for support as I was walking to the bathroom.

Once I got there I opened the cabinet and quickly grabbed the bottle that had the pills to suppress my pheromones.
When I opened it I was shocked to only see 1 pill
"!!"
This was bad, I'm supposed to take 2 pills to completely cover my scent.
Who knows how long I have if I only take 1.
Without much thought I put it in my mouth and swallowed
"I'll have get more quickly"

I went back to my room and got dressed in a long white sleeved shirt, a flannol, a jacket, and a coat.
Even when I took both my pills I was always careful, I was an Omega I had to hide my body and cover my scent since I was never sure when the drug would wear off.

After I got dressed I headed out and was quickly walking the streets, headed to the doctors when I heard someone call my name
"Nagisa!"
"??"
I turned around and saw Karma running towards me
"Karma! What are you doing here?" I asked surprised that he knew where I was
"No reason, I just had a feeling that you would be here"
"R-really?" I said, backing away from him, scared that he would discover my secret.
"What's wrong? You don't look happy to see me?" He said with a mischievous grin
"I-I'm not! I-It's just you caught me by surprise...."
"I don't believe you" he walked closer to me and I backed away again
"W-Why!?"
"You stutter every time you're nervous or lying"
"...I-I'm in a hurry"
"Where to?"
"...."
"Come on Nagisa, you don't need to lie to me. Remember the promise we made"
"....yeah" I responded, thinking back to the time we vowed we would be each other's mates
"I'll always protect you"
I looked down after hearing his statement
Even though he thinks I'm a Beta I still need to be protected....I hate being weak.
"Nagisa?"
"I don't need your protection" I said in a serious tone, even I was surprised at myself
"Nagisa? I didn't mean to offend you"
"I know I'm not an Alpha but do you really think of me as weak!?" I yelled, not sure as to why those words really got to me and why I was so emotional
Those words never really bothered me before. 
So why now?
"Nagisa!?"
When he yelled out my name it was then that I realized I was crying
Not wanting to waste another minute I ran off.
"Nagisa!"
I just kept running, not turning back
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Before I knew it I was at my doctors house.
"..."
I rang the doorbell and the door opened

When I entered I saw my doctor sitting on the sofa looking over some documents
"Koro sensei..." I spoke
He looked up
"Have a seat"
I did as was told and sat down infront of him
"How bad are your pheromones?" He asked
"I ran out of the pills, I need more"
"I'm sorry Nagisa" he lowered his head
"Eh?"
".....Even though I didn't finish perfecting those pills and making sure they were completely safe, I still gave them to you...I'm sorry, I just really wanted to help you become happy"
"......so What have those pills been doing to my body?"
"I'm afriad they have been suppressing your heats, but....you've been taking them for soo long that your pheromones have been building up"
"So what your saying is-"
"You're going to go in a heat that will probably even attract Betas"
I looked down at my lap
That explained why I was so emotional earlier...my pheromones were leaking out.
"What am I supposed to do now?" I asked
"I have nothing that could help you, you're just going to have to stay indoors until it passes"
"I see"
"I'll take you back since its dangerous"
"Thank you" I thanked him

When we went outside to get in his car I noticed that it was already dark
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During the drive I looked over at Koro sensei
"What would you recommend I do during my heat?"
"It would probably help a little if you nest"
"You mean surround myself with soft items?"
"Yeah, preferably soft items that have a familiar scent to you, like a family members clothes"
"....ok"

Once we arrived at my apartment I stepped put of the car
"It's going to be ok Nagisa, you'll be fine" he said
I nodded my head and closed the car door and watched as he drove off.
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Once the car was out of sight I took a turn around to walk to my apartment door only to stop and fall to my knees.
"*pant *pant *pant"
My heat was happening!
It was becoming soo strong that even I was able to smell the sweet scent I gave out.
'I need to get out of here!'
I stood up and wrapped both my arms around myself as a form of comfort only to be met by two Alphas infront of me.
"!!"
"What a cute Omega"
"And what a nice smell"
As I slowly backed away from them I bumped into someone and turned around only to see a whole group of Alphas
"D-Dont h-urt me...please" I whimpered
"Don't worry, it won't hurt~"
"Lets just have a taste of you"
One of them grabbed my arm, but I managed to pull away and run away from them.
Sadly they ran after me and when I took a turn it was a dead end.
"!!"
I was about to run back, but all the Alphas blocked my exit and cornered me
"You don't have to deny it"
"Yeah, we know what you're doing"
"You're trying to lure us out with that scent of yours"
"N-No!"
"Still pretending to be innocent"
They all got closer to me and pushed me against the wall
"We're going to have a fun time~"
They smiled as I shivered in fear infront of them.

Karma pov
After Nagisa ran off I was left alone.
Shockingly enough I wasn't able to catch up to him.

It bothers me that I no longer know what he is thinking.
When we were kids I used to always know what was on his mind...now I never know.
It pains me knowing that I caused him to cry.
I put my hands in my pocket as I continued to walk the streets.
I thought back to when we were kids.
Although Nagisa didn't look like the type of person to get into trouble, he was my partner in crime.
He was always smiling and never left my side.
It wasn't  until recently that he changed.
He always seems worried or bothered by something.
I just figured it was because he was a Beta rather than an Alpha. But either way I still loved him and still do.
But...when I think about what happened today...it could be because he no longer cares about me, he seems distant.
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I figured I should discuss my feelings with Nagisa so I headed to his apartment, hoping that he would be back by know.
As I was getting closer to the apartment I smelled the most delicious smell.
I was soo entranced by the smell I began to follow the scent until I realized.
An Omega!
If they were in heat they could be in trouble.
I quickly began running, following the scent, wanting to help the helpless Omega who was most likely surrounded by Alpha.
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When I got there I saw a crowd of Alpha  surrounding the Omega.
'These darn horny Alphas!'
I began knocking out the Alphas in the back and moved my way forward to help the Omega.
However, when I was able to reach them I was shocked to see Nagisa
"!!!"
I was horrified at the sight infront of me
He was hunched over hugging his knees with only his ripped shirt covering his body.
His arms and legs were also covered in cuts and bruises.
"....."
I stood there in disbelief

Nagisa...Nagisa was an...Omega!
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Once I had processed everything I turned back to look at the remaing standing Alphas
"You'll regret ever touching him" I glared
"Hey it wasn't our fault! He's the one at fault!"
"Yeah, he's the one who wanted-!"
Before he got the chance to finish his sentence I sunk my fist into his face, knocking him over to the ground and not once did I lift my hand off his face.

Once I lifted my fist I ran over to the other Alphas and punched their stomachs.

As I was fighting one of them I saw from the corner of my eye that one was about to attack me from behind so I threw the guy I was fighting over to him, knocking them both out.
Just then another guy came running after me, but I stopped him by pinching his nose with two of my fingers and twisting it until I heard a snap.
"Argh!"
As he was falling over on top of me I took the chance to knee punch him which knocked him out imidiently.
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Once I had finished off ever Alpha I ran over to Nagisa who was still shaking in the corner
"Nagisa!"
I removed my jacket and placed it over him
"I'm sorry Alpha!" He yelled
"!!!"
"Nagisa!?"
I was hurt that he would think I would hurt him.
"Nagisa, it's me...Karma..."
That didn't seen to help so I wrapped my arm around his shoulder
"....why didn't you tell me?"
"...."
"Why'd you lie to me? Did you think I would be disappointed if I knew you were an Omega?"
"N-Ngh" he slowly nodded
"Well I'm not...I'm disappointed that you didn't trust me"
"I...I'm sorry"
"I'm not like other Alpha, I would never hurt you"
"...."
"I promised I would protect and I will"
"...What if it's you I need to be protected from"
"You don't need to worry...because we're mates and mates stay together forever"
"..."
"I love you Nagisa"
"You don't care that I'm an Omega?"
"Of course not! I love you for you!"
Nagisa smiled lightly and leaned his head on my shoulder.
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We sat there on silence until I spoke up.
"...Next month when I turn 18 I'll mark you as mine, that way no other Alphas dare to touch you"
"Thank you Karma"
I smiled after hearing his response and kissed the top of his head.
Nagisa was going to be ok and I will make sure of it.
I will make sure his smile never leaves his face.
I'll never be the monstrous Alpha he is terrified of.

A/N: I had to go looking at a bunch of Mangas and webtoon to put this all together. The one I Used the most was
Our Omega Leadernim
You should all go read it because the plot is really interesting....and if you're a fan of BTS. Some characters are based off of them.