Had an idea.
Context, M/n is a parent. Muzan took a liking to during one of their fights. M/n is often threatened to be made into a pillar by Oyakata as a joke to make him work faster/more.
Male Reader x Muzan
M/n softly sighed as he rubbed his shoulder, he had been away much longer than expected. "Papa!" A child with e/c eyes ran, jumping on his back while watching the demon slowly turn into dust. The father rushed to cover their eyes before placing a light kiss on their forehead. "I told you not to run at night." He spoke softly before resting the child against his chest, the crow landed on his shoulder. "Hide! Muzan has been spotted!" M/n's eyes widened before picking up his child, he rushed through the forest. The night was already drawing near. He needed to run faster. "Papa! You right!" C/n shouted throwing a knife at the demon leader who chuckled, of course, it did nothing.
"Little C/n." His voice ran out, they were trapped. He grit his teeth, hiding the child in his arms. "My dearest M/n," wind brushed over his ear. "Don't tell me you've forgotten me already?" He threw his weapon at the demon. "Mister demon, don't hurt my papa!" C/n shouted, tugging at his pant leg. Muzan chuckled before his eyes softly glowed. "I could never hurt your father," the demon's hands held his, before bringing it up to his mouth. "Child," he turned to look at them, ah, he couldn't hurt them either. They looked too much like M/n. "Here's some money, go to a shop and eat some food."
Silence. "Papa?" They held the money in their hands. M/n shook as he gave a nod. "Go ahead. I'll be there in a bit." The child's eyes lit up and ran to go get some snacks and candy.
"You held up nicely," Muzan spoke as he stared down at the wet mess that he stroked. "You damn bastard. What if my child saw it?!" He shouted in embarrassment, he was quickly quieted with a kiss. "Shh. Our child." He whispered into the kiss, it slowly deepened as his hands slipped up his shirt. "Don't claim my child, my wife," Muzan kissed him deeper to shut him up. "Don't talk about her." He bit his bottom lip.
M/n shuddered, holding his arms tightly before sliding down the trunk of the tree, Muzan held his waist keeping him from sliding further down. "I hate that she took you from me," he nibbled his ear. "Then she had you join the demon corp. If only she didn't tell you who I was, I would've had you. You'd be living in bliss." M/n sighed in pleasure. "Then you got her pregnant," M/n glared up at him. "Then you killed her."
"She was giving birth to your child. Our wonderful child." "Don't claim my child," his breath hitched feeling his neck being bitten into. "Then I'll claim you in their place." He couldn't help but think of Muzan as a sly bastard. Muzan smiled at the state his beloved was in, how could he not be angry that the man wasn't his. That C/n wasn't his to call a child of his. It was okay, Muzan got the human to love him once. He can do it again.
"I love you." His eyes stared into the e/c eyes before fading away. "That bastard." M/n slid down the tree, panting heavily at the painful erection that was left of Muzan's presence.
"Papa!" M/n looked tired as he cleaned himself, he picked up his child and sighed at the dilated eyes. "How much candy did you eat?" "Hehe." He gave a soft smile before glancing at the mirror. Muzan smiled through the mirror.
He was always watching. M/n knew this. "Caw! Caw! Caw!" He glared at the crow. "Oyakata-sama has called for you!" Another headache.








