Yandere!Demon Slayer x Reader

Chapter Seven

🌸Flashback 900 years ago🌸
Since the day he was born, Muzan Kibutsuji was sick and very weak. After he entered his early teenage years, the doctor in his village had told his parents to not expect him to live till the age of 20.
The news sent his mom into a state of depression and his father ignored him more than he usually did.
But he didn't mind, Muzan was used to go through pain alone and the lack of parents didn't affect him much.
It was when he turned 14 that his life started changing,seemingly for the better.
His parents found a new doctor who would visit him, and he has been doing a good job so far. Muzan felt a lot less pain thanks to the medicine, sometimes he would even forget about his death.
"Kibutsuji-san my daughter will bring you the medicine I am making tonight, will you be home?"
"Yes doctor." Muzan answered while laying down on his futon.
"Excellent, considering you never saw her, she has long (h/c) and green eyes and usually wears a black kimono with a green haori." The doctor described her.
After he was finished, he left the house to look after the other sick people in the village, leaving Muzan alone with his thoughts.

Night already fell and Muzan with his parents was waiting for the medicine. The boy thought that the girl might have gotten lost, but he was proven wrong when a knock was heard.
"I will go, it's probably the doctor's daughter." Muzan said and went to greet the stranger.
Opening the door, he was surprised to see a beautiful girl around his age, standing there with a gentle smile.
"Hello! Are you Muzan Kibutsuji?" She asked.
'Her voice is gentle...'
"Yes that's me. Are you the daughter of the doctor?"
"Yes! My name is Misaki (L/n), I am sorry for being late I got lost a few times." She chuckled nervously nd Muzan did the same, finding her cute and amusing.
"It is alright. Thank you for bringing me the medicine. Have a safe return."
"Thank you."
Muzan watched her walk away for a few more seconds before walking inside.
'She is very beautiful... I wish I could have talked to her more...'

Seven days later the doctor came again for his check up, this time the girl accompanied him. It was surprising to Muzan, but it was a welcoming surprise.
"Ahh Muzan-san, I see you are a little better than when I left you."
"I do feel alright, thank you."
"I'm happy to hear that." The doctor smiled and turned to where his daughter was.
"I hope you don't mind, Misaki-chan said she wanted to come and see you."
Misaki gave him a small smile and waved, all Muzan did was nod at her.
"No, I am fine with it."

After the check up was done, the doctor went to talk to Muzan's parents while leaving to two teens alone.
"So why are you here?" The male asked.
"Huh? I just wanted to talk to you. You seem like a interesting person."
Muzan rolled his eyes at those words, he was a sick kid who will die soon, there was nothing interesting about him.
"Also I wanted to make some friends."
That caught Muzan's attention, it was the first time he heard from anyone that they want to be friends.
'Might as well give it a try...'
"Alright then."
Grinning Misaki sat next to him on the floor and they started talking about themselves.

4 years later...
Over the span of the next years, Muzan and Misaki became close friends and later down the line got married. They didn't live the most lavish life, but it was a happy one.
One thing that always bugged Muzan was his illness. His time is very limited, and while 4 years ago he acted indifferent, not he was afraid of dying, afraid of leaving Misaki behind. So on day a different doctor offered him a strange medicine that he said would cure him.

"It did not work! You said it would work!" Muzan yelled at the man, who shaking under his stare.
"Sir I still need to give you-"
The man couldn't finish his words since Muzan's rage blinded him enough to kill him.
"Useless..." He muttered.

"Muzan-kun why do you not want to go to the market with me? You said you felt better." Misaki asked her husband who was sitting in their dark bedroom.
"Ahh maybe next time Misaki, I don't feel so well after all."
Walking over to him, she gave him a kiss on the forehead and smiled.
"Alright, but we still need to call the doctor to check up on you. Also you have been staying away from the sun a lot, that can't be healthy either."
Once she was gone, Muzan sighed in relief.
"I can't do this much longer. How am I supposed to tell her that I am a demon now? That I crave human flesh and detest the sun? Misaki please forgive me for what I did. I wish I never accepted that medicine..."