Osomatsu-san Oneshots (Book 3)

Protective (Alpha! Matsu Bros x Omega! Little Brother! reader)

For BadEnglishGirl7
Reader is 25
Brothers are 28

Y/n is the youngest of the Matsuno family. As a result he gets a lot of attention from his parents and older brothers. All of his brothers were alphas and they just assume that y/n is too. However, he isn't. Y/n is an omega but he would never tell his brothers that. Why?

He felt embarrassed that he was the only omega. So he kept silent about it by taking his suppressants in secret. He has done this for 7 years without his brothers finding out.

I wave goodbye to Karamatsu as he left the house. He was apparently going out for a stroll around the park. Now with him gone I was all on my own which was fine with me. I love my brothers but I wanted to relax today. I lay back with a content sigh and start thinking of something to do. Then I remember that comic that Osomatsu has bought for me yesterday and I still haven't read it yet.

I sat up with a hum and stood up but before I could go get the comic I felt heat flood through my body. My eyes widen and I rush to the bathroom. I had a hidden stash of suppressants in there. I open the door and quickly search for the bottle. When I found it I quickly open it and my heart drops when I saw that I was out. I throw it to the floor in anger with a curse.

"How did I not know I was out?!" I exclaim and whine as my heat flares up. My legs were starting to shake and I slide down the wall with a whimper before I pull my legs to my chest. "What do I do? I can't go out like this...I could wait it out until mom comes back but that could be a good hour." I say before pushing my head into my folded arms.

After some time passes I let out a whimper as my heat completely took over my body. I was trembling as sweat had soaked everything. My shirt, My pants and my underwear were soaked. Though my underwear was wet with both sweat and a small amount of precum. I was now panting as I let out whines and whimpers. "Why can't this just end already?" I whine softly before tensing when I hear the front door open.

I froze and cover my mouth when I sensed an alpha. One of my brothers were home. "Y/n? You home? I know I'm back early but-" I tense as I hear Choromatsu before he abruptly stops talking. I could hear his footsteps as he makes his way over. "Do you have an omega with you?" He asks and I could hear the change in his tone. My scent was clearly affecting.

I tense up as the bathroom door was pushed open. I hear him hum and I look up at him through lidded eyes. I saw his eyes widen before he places a hand over his nose and mouth. "Y/n." I hum and cower back "is the scent coming from you?" He asks and I nod before hearing him gulp. I look at him as he walks over and crouches down. I flinch as he reaches out to hold my face.

"Sh~ Sh~ it's okay~ you're okay~" He coos and moves to pet my head "can you stand?" He asks and I shook my head "that's okay. Come here." He says before helping me up, placing my arm around his shoulders and wraps his arm around my waist. I whine softly and cling to him as he helps me walk up to our bedroom. He sets me on the couch and moves to pull the futon out.

Once it was set up he moves to place me in the futon. He pulls the cover over me and I look up at him with a whimper as he scratches my head. "Sh~ it's okay~ I'll call our brothers and we'll help you okay?" I nod and he pulls away making me whine softly. "It's okay. It's okay. I'll be right back." He says before leaving the room.

When he came back he was on the phone. He sat down beside me and scratches my head as he talks on the phone. "Yeah can you gather up the others and get home now. It's an emergency that's why. No I'm fine it's about y/n." He says and I hear Osomatsu asking what happened and if I was okay. "He's fine and on the way back can you pick some heat suppressants...Hello?" I look at him with a hum and he puts his phone away.

"He went silent before just hanging up." He explains and I hum "You aren't mad at me are you Choromatsu-niisan?" I ask shyly and he hums "No. why would I be?" He asks and I glance away "..because I didn't tell you I was an omega." I say and he stops scratching my head. He pulls his hand away and I look down sadly before gasping as he pulls me up into a hug.

"C-Choromatsu-niisan! W-What-" "I get it. I can understand why you didn't want us to know...though I don't know why you would hide this..you should have told us so we could help and protect you." I felt his grip on me tighten and I hum "Please don't keep stuff like this hidden from us." I hum and wrap my arms around him. I hum and nuzzle my face into his shoulder. I felt my eyes droop before shutting and I fell asleep.

When I woke up I hear talking downstairs and felt arms around me. I turn to see Jyushimatsu and he hums "you okay y/n?" He asks and I shook my head "n-not really?" I say softly and he hums before holding me close. "Choromatsu-niisan! Y/n woke up!" He calls out and I hear footsteps rush upstairs. The door was thrown open and I look up to see all of my brothers.

"He's still trembling." Jyushimatsu says as he rubs my back and I cling to him with a whine making him tense. "and he's starting to get clingy." He adds and I felt myself get pulled away before I was sat up. I whine softly and reach out for Jyushimatsu before a hand lightly pets my head. "It's okay y/n. We got your suppressants now." I hear Karamatsu say as he pets my head. I look back at him with a hum when he pulls his hand away.

I saw the bottle in his hand before he took a pill out. "Here. Open your mouth." He says and I open my mouth with a whine. Karamatsu blushes softly before placing the pill in my mouth and I swallow it before laying my head on his chest. "Now. We just wait till he feels better." He says before rubbing my back while I nuzzle my face into his chest.

When I did feel better my brothers refused to leave my side and did not let me go anywhere on my own. Of course I knew this was because they wanted to protect me so I didn't complain but they became super protective over me. If I went outside I either had to have one of them come with me or all of them.

I don't blame them for worrying. I wasn't marked yet and they didn't want some random alpha marking me. They were especially worried that if I was in public alone and I go into heat that an alpha might force themselves on me.

Yes they were protective but they had reason to be.

Not only was I their little brother but I was an omega.

They would protect me with their lives.