Chapter Text
Every dim corner of this godforsaken mansion only served to make Kibutsuji Muzan one thing: Mad. Very, very mad. The eternal darkness that plagued this place constantly reminded him of the one thing he so desperately wanted, yet forever seemed to be out of his reach. The warm rays of the sun always found a way to elude him, constantly slipping through his pale fingers, making a fool out of the man who was supposed to be feared as the strongest being this world had ever known.
Well, he would be. Soon enough. For now, Muzan needed something, or better yet, someone to take his frustrations out on. “Tanjirou!” He all but snarled, and Muzan felt about ready to snap the boy’s neck if he didn’t appear a moment later. Any lackey worth their weight wouldn’t dare to keep him waiting.
Thankfully, he did.
He’d come running, even, long, dark hair gently bouncing behind him. It didn’t do much to quell the anger already burning inside Muzan’s gut, but the display of loyalty had certainly helped. Although he was trapped here in eternal darkness, he wasn’t alone. No, he’d managed to seal this small piece of the sun here along with him, and it was about time Muzan took full advantage of that.
Tanjirou said nothing. He knew his place, knew not to speak before his master did. Muzan appreciated that. Competence, he found, was an exceedingly rare quality - even amongst his own Upper Moons. He briefly wondered what they’d make of the boy he’d found and kept hidden away on little more than a whim, a passing fancy to help kill all the dreadful time he had on his hands.
When Muzan found that Tanjirou’s eyes were expectantly staring up at him, almost glittering in anticipation of his orders, he decided it didn’t matter anymore. There were far more pressing matters at hand. Namely, how he was going to keep himself entertained. Perhaps Tanjirou could help with that.
- -
“Is this…is this really all you want from me?” Tanjirou practically squawked, and for what felt like the first time in a hundred years, Muzan had to repress the sudden urge to laugh.
“Yes,” He growled against the shell of his ear, short, decisive. “For now.”
This wasn’t good. Muzan felt like he could lose himself in the vast expanse of Tanjirou’s kindness, his natural body heat bringing warmth to the tips of his fingers just as the sun once had. He wouldn’t give up this feeling, not for anyone. This former breath of the sun user, his former life and pride, it all belonged to him and him alone. He snaked a possessive hand around Tanjirou’s waist, pulling him closer, burying himself inside that enrapturing warmth.
The silken sheets began to wrinkle as Tanjirou involuntarily squirmed, trying to adjust to the sensation of someone holding him so close, painfully tight. Something about Muzan was different today, and he didn’t know what. He wanted to say something, but knew better than to speak out of turn.
“Oh, Tanjirou…” Muzan suddenly whispered into his ear, and Tanjirou visibly tensed, staying stock still. His heart was thumping almost painfully hard now. “Please, don’t tell my wife about this. I’m afraid she’ll be simply furious.” Tanjirou bolted upright, breaking free of his hold in an instant.
Muzan hissed, veins bulging in dissatisfaction. “You dare to defy me?”
Tanjirou hastily pulled the Yukata that had been steadily slipping down his narrow shoulders back up, more than embarrassed, now ashamed.
“You should know...” Muzan paused, seeking to heighten the tension hanging thick and heavy in the air. “I don’t take too kindly to traitors.”
“I’m not - !” He urgently protested, more to defend his honour than he was concerned with saving his own skin. “This isn’t right!”
The flames burning away inside Tanjirou’s eyes were absolutely righteous, and Muzan hated the very sight of it. “How can I lay with you like this if you already have a wife?”
Hah. His voice was weak, presumptuous. Muzan could work with this.
“I’m disappointed in you, Tanjirou. Where has your sense of humour gone these past 100 years?” The brat instantly perked up at that, hope soon returning to his fiery eyes.
When someone earnestly wants to believe in a lie, it becomes so much easier to fool them. “Now, come back to bed. We still have much to discuss.”
For once, Tanjirou was happy to follow orders.