Kimetsu No Yaiba X Fem! Reader Oneshots

He's Just A Kid (Muzan X Fem! Reader)

Muzan was absolutely pissed at Y/n, she has been ignoring him all day and hanging out with that weird spider child lower moon 5 Rui. It wasn't even Rui's doing it was Y/n's she has been treating him like a baby and not a warrior.

Y/n literally was babying him, she was hugging him, calling him sweet names, and even carrying him-. Muzan was just staring at them both from afar, he knew Y/n could feel his stare but she was focusing on the child in the room.

"Your so adorable Rui!!" Y/n squealed and she kissed his forehead making his eyes widened but went back to his normal face. "Can I see your Demon Blood Art?" Y/n asked smiling, Rui just put his hands out showing the web in his hands, and shot some to the ground creating a small cage. Y/n clapped her hands and hugged him "Amazing!!" Y/n said.

Muzan was just there looking at her like she was crazy, 'It was a tiny cage how was that amazing?!' Muzan thought. Muzan went towards them both and Y/n was picking up Rui like a baby?! When she turned to walk away Muzan was right in front of her and she just smiled. "Hey Muzan~," Y/n said and tried going around him to walk away but he grabbed her shoulder to stop her.

"Where are you going with the brat?" He said making Y/n lose her smile, "He isn't a brat and this is Rui remember. And I'm taking him to our bed of course he must be tired!"Y/n said then walked away. Muzan of course wasn't taking that shit and followed them both.

The upper moons were just watching and Douma said "Y/n-chan loves that child like it's her own! It's adorable!" with a fake smile. Akaza groaned from hearing Douma's voice, Douma put his arm over Akaza's shoulder and said "Who's that kid again?". Akaza rolled his eyes and said "It's lower moon 5 Rui, and get your arm off of me!" and pushed off Douma's arm.

Kokushibo watched from afar not really caring but was staring at Akaza and Douma arguing.

-

Y/n put Rui to bed, blowing away the candle and closing the sliding door. When she turned from closing the door Muzan was in front of her close to her face "What do you think you're doing taking him to our bed!?" Muzan said with his annoyed voice. "Well, first of all, be careful I almost dropped the candle it would have burned down this place. And second where else do you expect him to sleep? On the floor? No." Y/n said back

"It's not like he's your child, why are you treating him like it?!" Muzan said raising his voice. "You're going to wake him up wait," Y/n said grabbing Muzan's wrist tightly bringing him away from the room. Muzan was glaring at her, he knew Y/n was slowly getting angry by the pressure she was putting on his wrist. As they were far from the room Y/n glared back, Y/n was never afraid of Muzan and he knew that so he had to effect on her. And he would never put his hands on her, so all he can do is yell.

"He's not your child! Your not his mom! Why can't you understand that already! I've been telling you this ever since I turned him into a demon! You were there once I turned him!" Muzan yelled at Y/n, Y/n rolled her eyes and glared at Muzan "I know I'm not his mother Muzan! You don't think I know that?! He doesn't have parents! Yes, he has a family but that family is forced to love him cause that's all Rui wants a family to love him and care for him! His parents tried to kill him Muzan! I'm going to keep treating Rui like this not cause I'm forced but because I want to. I don't care what you say!" Y/n yelled back walking away from Muzan.

Muzan growled and walked away as well, 'If Y/n was just like these other useless demons who feared me this what have been a lot easier' Muzan thought. Y/n went back to the room and lit up the candle to see in the room Rui was gone. Y/n began to panic she looked around and saw Rui standing up, she took a deep breath and said "You scared me for a bit Rui I thought you were missing"

Rui turned back to her and gave Y/n a small smile. Y/n felt her heart explode Rui never smiles, Y/n ran to hug him which she did. "I'm going to talk to Muzan Rui. I want you to stay here with us, I don't want you putting your life in danger Demon Slayers are getting more popular and if I ever lose you or Muzan I would kill all of them. I will protect you and love you as my child Rui, stay.." Y/n whispered while hugging him.