𝗦𝘂𝗰𝗰𝗲𝘀𝘀𝗼𝗿 × 𝗗𝗲𝗺𝗼𝗻 𝗦𝗹𝗮𝘆𝗲𝗿 [OLD]

𝖢𝗁𝖺𝗉𝗍𝖾𝗋 𝖳𝗁𝗂𝗋𝗍𝗒-𝖳𝗐𝗈

Funny how history repeated itself.

Kokushibo had once shared something with y/n.

It was after her Father died, while he was helping her make her way back home to her brothers and her sick Mother.

Three days. It took three days for Kokushibo to turn into a demon when he first received blood from Muzan while he was a Demon Slayer.

Back then, as the dull eyed y/n slowly made her way back home with the demon supporting her, she could only imagine how much it hurt.

After the battle with the Upper Moon, she got to experience every single thing he had all those centuries ago.

Two vials of his blood. That was what Kokushibo had given to y/n, fulfilling his part of the deal.

Y/n doubted she would be able to get it to Tanjiro herself so she would have Shiori take it to him.
That is... if the cat could get to it alive.

As for y/n's part of the deal...

She would become a demon.

This wasn't the first time she'd had to swallow so much of a demon's blood though this time, it was far larger an amount than what she was used to.

The pain was nothing new, her body feeling as though it was being ripped apart from the inside out but it was never something that she was able to get used to. All y/n could do was bear the pain.

The process wouldn't kill he'd, that'd been confirmed from the several other times she'd been exposed to Muzan's blood, but it hurt her just as much as it would any other person.

It was a surprise to her, even through the blinding pain, that Kokushibo had stayed with her.

He held her as though she were a small child, allowing her to squeeze his hand and simply staying there without saying a word.

He had moved to a cave before the sun could rise but as soon as night fell once more, he wrapped y/n up in his kimono and left to go get her some water.

Y/n occasionally did manage to fall asleep, her dreams plagued with a voice which didn't belong to her a memories which weren't hers either.

But in the end, it was three days.

Three days.

Three days and y/n still wasn't a demon.

She couldn't become a demon, Kokushibo realized that when y/n had calmed down and all traces of Muzan's blood had gone poof from her body.

"I'm going to become strong!" was what she had told him all those years ago when they first met.

That teary eyed little girl who had left home just for some soba and was ready to shout profanities at a demon over twice her size.

Kokushibo smiled gently, patting the sleeping y/n's head as she rested peacefully for the first time in 72 hours, "You did it. You did exactly as you said you would. I'm... very proud of you."

Almost as though she could hear him, y/n smiled a little in her sleep as she grabbed her teacher's wrist and enjoyed the coolness of his hand resting on her face.

There was still some time before the sun would rise. Kokushibo could stay with her a little longer.

When y/n woke up, Kokushibo was gone.

The sun was up and all her teacher left was the two vials of Muzan's blood had been placed in a small bag along with some food which y/n only took a bit of, knowing that it would take some time for her to get to the closest town.