Kokushibo's new young brother

How it all started

/Tanjiro's pov/

When the mission was done, I, Zenitsu,and Inosuke were staying at Shinobu-chan's butterfly house to recover there. After the three of us were sleeping, I smelled something off, it was almost related to Muzan kibutsuji's blood. I shooked my head and ran towards the door and saw upper moon 1, Kokushibo "Wh-why are you here?!?" I yelled as he spoke "Because of you, Tanjiro kamado" then he pointed at me. Then I felt... dizzy, I slowly fell on the wooden floor leaning sidewards at the sliding door facing Kokushibo. "ngh~" I groaned then started to lose consciousness....

/Kokushibo's pov/

As I put a sleeping spell on Tanjiro I slowly picked up Tanjiro bridal style then the pillars noticed my presence and saw me carrying Tanjiro, then "What are you doing Kokushibo" Said giyuu with an murderous glare, they pulled out there nichirin blades then I asked Nakime to teleport us to the infinity fortress fast, then she pluck a sound that teleported us to the infinity fortress and to my room, then I changed Tanjiro's clothes to a white robe. then I put Tanjiro to my bed, waiting for him to wake up...

/Tanjiro's pov/

"Mhmm~" I groaned rubbing my eye As I woke up from my consciousness, I found myself in a room then I saw Kokushibo cleaning his nichirin blade "W-where am I-i" I stuttered then he responded "I see your awake, Tanjiro kamado" he walked up to me and sat beside me, facing me and slowly touching my cheek, slowly rubbing it with his thumb and said "You have two choices, choose wisely" he stopped rubbing my cheek and I sat up to listen and obey quietly since I don't have my nichirin blade in my waist and I can't fight with my two bare hands, then Kokushibo continued "Accept me as your big brother and stay with me for Eternity, or refuse and I will kill all of your friends and the hashira's in front of your eyes and force you to be with me" my answer is obviously accept him as my big brother, I can't let anyone die because of me, including Nezuko. As I was losing from my thoughts, I noticed that Kokushibo hugged me to keep me calm and relaxed, but it did while brushing through my hair, waiting for an answer, I flinched as he did that for a while then answered "I-i a-accept y-you as m-my brother K-kok-kushibo" I stuttered as he stopped brushing my hair instead, he patted my head and said "Wise choice, little Kamado and please call me nii-san" then I replied "O-okay N-nii-s-san" I clinged into his yukata and looked up to Kokushibo and he reminded me of my past father when I was a child, I started to cry "hicc....hicc...hicc...", as Kokushibo looked at me with a shocked glare, he pulled my head to his chest, slowly rubbing his other hand to my back, slowly but surely rubbing it to stop the crying and making me calm and relaxed for a while, then he said "Don't worry, I won't harm your friends nor the hashira's, I'll be here for you, Tanjiro". As he said those words, I slowly pushed myself and wiped the tears that are on the eyes then, I suddenly felt in my father's hands once again, then I suddenly feel.... Sleepy...

/Kokushibo's pov/

As I saw Tanjiro feeling sleepy then he fell into my arms, I gently lifted Tanjiro bridal style once again and put him to my bed for him to wake up. Maybe I can meet him with the other moons and get along....

/Giyuu's pov/

"We need to get Tanjiro back" I said while glaring at them "But how do that, we don't know where the infinity fortress is??" Said Shinobu. "Maybe at night they would have a mission to kill someone and maybe bring Tanjiro for a distraction" as Mitsuri said nervously "Then how do we know where to find them then" said Sanemi with curiosity "Guess we will have to wait" Master Kagaya spoke, then appeared with his children holding her hands showing her the way to sit....

So this is how it all started.....