Osomatsu-san Oneshots

The Promise (Father! Karamatsu x Daughter! reader x Yandere! Ichimatsu)

For CryptOfDrawings
This will be a long one. I was inspired.

-Karamatsu POV- (age 10)

I was watching the clock with anxiously. As soon as school got out I needed to get to her. As soon as that bell rang I rush out of the room ignoring my brothers. I ran out of the school and towards the city bridge. I went to a small shed that was near the bridge. I open the door to see y/n playing her stuffed bear. I sigh in relief that she was okay and walk over.

"Hey y/n." I coo and sat down to hug her "Daddy!" She coos and hugs me back. Y/n was a 3 year old baby I found about 4 weeks ago. She was abandoned in an alleyway crying. When I found her she calmed down and started cooing. So I took responsibility over her and started caring for her. "I hope you weren't too lonely. You must be hungry." I say and reach into my bag. I pull out an apple and a bottle of milk.

I stood up to grab a baby bottle and transfer the milk into it. I pull y/n into my arms and bite a bit of the apple. I fed her the piece and she coos happily. I continue that process till the apple was gone and held the bottle for her as she happily drinks the milk. I smile softly and kiss her forehead.

"Karamatsu-niisan?"

I jump a bit making y/n whine softly. I quickly calm her and turn to see my brothers.

Uh oh.
....

"EH?!!" They exclaim when I told them the story and y/n starts to cry from their yells. I quickly hold her close and calm her. "Karamatsu you're 10! You can't take care of a baby!" Choromatsu shouts and I glance away with a frown. "Why? I think I'm doing alright." I say with a bitter tone and Choromatsu sighs "Karamatsu think about his rationally. You can't-" "I AM THINKING RATIONALLY!" I shout but immediately go quiet as to calm y/n.

"I know I am a kid myself but I don't care. She was left abandoned by her parents who clearly didn't want her. I have already prepared myself for what I'll have to give up and what I have to go through. I have accepted it because I want to take care of her. You guys can't stop me." I say and Choromatsu was about to chime in but Osomatsu lays a hand on his shoulder.

He walks up to me and looks at y/n. "You really want to take care of her?" He asks and I hold y/n close "yes. I want to help her." I say and kiss her forehead. Osomatsu sighs with a smile before patting my head "okay but let's at least tell mom and dad." He says and I smile. "Thank you Osomatsu-niisan." I say before we head home.

They were both surprised but I was so happy when mom said we could adopt her. Though I was surprised when she said that I was now her dad by law. The surprise was instantly replaced with joy. I was so happy.

By law y/n was my daughter and I felt so happy.
....
-Y/n's POV- (age 7)

I was sitting at the table drawing two different pictures when Ichimatsu came in. He sat down beside me and smiles "what you drawing y/n?" He asks and I blush covering my drawings. "Nothing!" I exclaim embarrassed and he smiles before scooting closer trying to peek. "Nuuuh! Don't look!" I whine and he smiles before tickling my sides. I laugh and he continues until I fell back.

He took the chance and took one of my pictures. I blush when I saw which one it was. He hums and looks at me "y/n? What is this?" He asks and I blush harder "it's a drawing...of us" I say and he hums "any reason you drew these love hearts?" He asks and I glance away. "...it's because..I like you...I like you like you." I say and he hums "it's a little embarrassing but I kind of want to marry you." I say and glance at him to see him blush a little.

"Um..well that's sweet and I do like you but.." I scoot closer "what if we get married when I'm older!" I suggest and he hums before shrugging "okay. Sure." I smile and hug him "I promise Ichimatsu. One day I'll marry you!" I say and he hums before hugging me back. I saw the door open and see my dad return from his part-time job. I grab my other drawing and rush up to him.