Chapter Text
Muzan Kibutsuji did not have to learn the single truth that is, if he wanted something to be done, then he might as well do it himself. There's no use relying on anyone else he knows would eventually fail. Not demons he converted. Not humans he threatened. The only one he could spare this assumption… Would be Kokushibou. His Upper Rank One, a man he refers to as his 'business partner" the one who had stayed by his side for hundreds of years. He'd gladly give the swordsman this title, if it hadn't been for the contradiction he faced in those same hundred years.
The same man who did not hesitate to prove his loyalty by beheading the leader of the organisation he once had followed so religiously. Lost all his guts when it came to courting. It's disgraceful. Borderline pathetic… This very reason proves that Kokushibou is not as reliable as he thought.
"You're awake." The Demon King shifted his gaze. From the scattered papers and colourful test tubes on his table, to the feeble cowering figure lying flat on the red leather couch. A gift he received from a demon he sent abroad far out of the country. An imported piece of furniture that happened to fit his taste.
By the amount of sweat and shock the human emits, it passes through his mind the dirt that his valuable furniture would imprint on. He is not below the responsibility of cleaning an object, but rather, said object wouldn't be able to be replaced so easily.
But. He did nothing to reprimand such movements. Stilled by his own desires, his eyes traced the wriggling creature. Struggling like a worm, yet his disgust has been far too set aside and removed when he committed to the bit. The purpose of it all is to help Kokushibou. Yes. He believed Kokushibou would benefit from this 'experiment' and he expects to see a productivity improvement soon enough.
That thought alone put the Demon King in a slightly better mood. Relationships are foolish. For him, the only one worth keeping is transactional or a sacrifice. He shouldn't have any more distractions to complete his goal of achieving true immortality. He said that, believed in those words, but 'Kokushibou.' His body is too far gone to be controlled by his mind, or his mind was encouraging it from the first place.
Kokushibou is the exception. He acknowledges himself. A King should revel in their own needs and wants. And he knows what he wants. Those years of waiting are no more. He's done with leaving trails and hints, just for Kokushibou to effortlessly dodge and ignore his attempts, as if they were simply rocks in his pathway, placed there to watch him stumble. Unfortunately, he didn't know that he was meant to fall. Take the bait and he will make the man kneel once more at the hands of the King he worships. Just as he did the night they first met.
Now, after consulting many of his demons who he deemed them worthy enough of his time. He has constructed a solid plan, where there is no way Kokushibou could misunderstand his gesture. Yes, he has surprised him more than he realised, since he believed all his previous tries wouldn't be misunderstood, if it was anyone but Kokushibou to receive it, but this should change that cycle. It should.
Thud
Muzan was slightly more present in the world when he watched the gift he prepared struggle far enough until he fell off the furniture. Landing face-first to the cold hard wooden floor before continuing to move again. Akin to watching a blind folded hog hit a tree, he supposed that's not a bad comparison. He acknowledged it's a human instinct to be scared when one wakes up gagged and blindfolded.
The instruction he gave to the demons for this mission was to subdue without damaging. Therefore the slayer before him was as unthreatening as an infant. Of course, his probability was still low even if he could move, no human stood a chance if it was him they were against. But if he were to have this human's presence as a constant, he might as well find a way to tolerate his existence.
The instinct to survive defeats all of the other rational parts of the trapped human's mind, at least, that's what he assumed. The fear of keeping his mortality, how the Demon King had long forgotten that feeling. He is not capable of reading into someone who does not share his blood. And he will give the rights to convert this slayer to Kokushibou himself. That is the gift Muzan Kibutsuji had prepared.
Kokushibou could use a pet. After all, he has been seeking out this particular human for weeks with no reports of his intention. If it had been any other demons he would've asked what authority they had to be occupied by a human unrelated to their job. If it was Kokushibou? It's a privilege. Kokushibou knows best what he will receive from him would not be easily accessed by anyone else under his control.
With one hand he lifted the human by the crook of the slayer's uniform, placing him to lie on his stomach on the couch. His hand moved from the crook, directly shifting to hold a tight grip behind the slayer's neck. "Stay still." He could feel the shiver that ran through the human's back until he ultimately forced himself to seize all of his trembling as best as he could. "Good." He moved even further, settling on the ruffled spiky hair on the boy's sweat-covered head. "If you keep this up, I'll consider giving you a treat." Satisfied, he returned to his desk. A lowly boy who has just learned his place and does so very quickly. His instincts are better than most, that's a start.
By now the human must know that he is under the gaze of a demon. And he might not know who's holding him down, but he's willing to put aside his egotistical pride as a demon hunter and know that in this instance, he is indeed the prey.
With that matter finished, all he needed was to wait. He had summoned his most trusted Upper Rank, but he hadn't put any rush into it. Kokushibou is the pinnacle of outcomes, he doesn't want to fill his life with more unwarranted stress, as much as it is fun to see a cold sweat formed by the cold-blooded demon sometimes. He mustn't be so cruel, after all he should be open to the idea that he might as well be a factor for waiting this long in the first place.
Muzan Kibutsuji does not chase, but somehow, just like all the other exceptions, Kokushibou stood his ground. He is a man who willing bowed before him, but clearly, he hasn't bowed low enough. Or was he too far gone? In either case, everything will change. Changes for his benefit, are the things he'd gladly excuse.
He found himself not being able to find a distraction to get back to being engrossed by his work. Returning to the human's side, he sat by the edge, even though the human had long curled up on himself, trying to portray himself as something small and insignificant as he could be. With his hand inches away from the shaking body. He has thoughts of cleaning this boy and perhaps dressing him in something other than the uniform that the people who wanted him dead would wear.
If he does so, would Kokushibou not recognise him? He is a man who strives for perfection. And to receive perfection he must gift the same. Why does Kokushibou seem to favour this boy? He'd find all about it later, he's sure. If he had to guess, it might have something to do with resemblance. Muzan gathered very little about the young man's personality. Based on the few hours he's spent in the same room with him, he couldn't capture much.
Kokushibou is and always has been difficult to read. And he will change that. The distant strum of a biwa echoes in the background. He's here. His partner had arrived.
"You've requested me, Master." Kokushibou sat as a graceful samurai, kneeling in front of the man to whom he had dedicated his loyalty and trust. With a simple flick of his hand, Nakime understood his orders and they were moved to somewhere much more private. Muzan had many offices in the real world, but his best and admittedly favourite was located in the Infinity Castle. "Stand up." Before this, he had sent his Upper Moon on a false mission, to scout the place that was already proven to have no lead on any of their main objectives.
It was however, a place Kokushibou seemed to enjoy roaming in, as coincidentally or not, it was the territory his favourite slayer would be located in. Does he wonder however, that the slayer was nowhere to be found? Maybe, considering he does not usually have much to any emotions visible, but Muzan could tell he was displeased.
The Demon King himself does not have much to be satisfied with frequently throughout his life. Very little impressed him, even less that appeased him. He who has lived long enough to see the rise and fall of civilisations is often disappointed by change, flowing like water, in the end no matter what one could achieve with one's greatness. Another could topple a century or two later. It does not have to be that way, not for him, who is just a few steps behind in reaching true divinity.
Yet being an immortal does not mean he has won. "You, Kokushibou. Had been a presence by my side for almost five hundred years." Muzan spoke with a cold focused voice, clearing the Upper Rank's head each time he heard him speak. It's not often his tone could be so… "Gentle? You flatter me." Muzan scoffed without much thought of it.
He leaned back to his desk, his body language showing no sign of behaviour Kokushibou would've immediately recognise. Trying his best to hide it Kokushibou is utterly confused. And the King chuckled at that predicament. Leaving his poor servant to wonder what the reason was for his summoning.
"There are demons out there who have changed, despite their capability not to." Muzan took his recently filled book, a rare sight considering most were shredded before half of them were dirtied with ink. "Their wills dissipated or their appetites were not enough." He travels through his book, ending on the page of detailed demon biology. The deterioration of the mind, mostly experienced by demons too attached to humanity. "Most demons do not manage to live that long, some die in the first decades. Some wretchedly turn their back against the one who made them be. You are not one of them, are you, Kokushibou?" He needn't answer. His job at this point was to listen. He wished he could've stayed kneeling on the ground. Standing on Muzan's side was not the correct way to fully appreciate the benevolent way he was saved.
"You, are a constant. A pillar who will stay for all of eternity." Kokushibou had not once shown the factors of deterioration, an accomplishment only they share. "Here. By my side." He returned the book to where it belonged. "And, as an 'appreciation' for your hard work, I believe you deserve a gift." Upper Moon One, who had been silent up until that point began to speak. "I don't deserve-" Muzan gestured with his finger in front of his lips, reminding him that he had yet to be granted permission to speak.
"Open that door." He moved that same finger toward a wooden entrance by the corner of the room. Kokushibou has no guess as to what could be behind said door. Yet an order for the King is not something he could easily dismiss. Watched by his master, he walked motionlessly to the corner, Muzan stood amused in his place. Strangely, he was waiting.
By the time he looked through the door, Kokushibou understood everything.
"Now, I'm curious. Enlighten me Kokushibou, what exactly is it about this boy, that made you so disrupted in your work?" Muzan stood just a few steps away from the human, his voice was more or less… amused, a sign that confirmed he wasn't fully offended by his action. He watched closely as Muzan's pale fingers grazed the captive, a contrast to the blood-warmed skin underneath.
"Forgive me…. For my insolence…" Kokushibou did not hesitate to drop to his knees once again, his head bowing lower and lower until he could feel the ground touching his forehead. "I had not… meant to be occupied by such a diversion…" That was far from the truth, if Kokushibou had indicated a diversion, he would have eliminated it, first and foremost. Just like what his Lord would've wanted.
"And yet you did. What is your excuse for this?" The hairs of the human body stood up in alert, resembling a cat that had been spooked. "I… I have none. Please, punish me accordingly." In the past hundreds of years of servitude Upper Moon one had not once quiver in shame, his most trusted pawn falling behind was a change he would accept, but his stoic shaken, his figure shrinking on itself? It's something Muzan doesn't mind seeing once in a while.
"You care for this child, don't you?" The Upper Moon tilted his head further. Without the questions needed, the answer was clear. The rapid movement of Kokushibou's eyes between him and the child. The trail of the hand that lands leisurely on the open neck. "Perhaps you have an excuse for that?" Muzan exudes an ambience of disappointment as any King would when their servants are arrayed. He fiddles with the rock ornament hanging on the boy's neck, tied by a string.
The rock was shaped like a coma, a magatama that resembles luck. How curious. How much luck does this boy possess to be able to smitten his Upper Rank so?
"It was... A matter of intrigue." Kokushibou replied, his voice returning to that of a cold and calculating business partner, ready to strike a deal. "I saw… the potential. That I consider I could extract from him." His fingers, which were trying to find stimulation in this conversation stopped trying to undo the knot that was holding the collar altogether. "Are you lying?" A churn of desperation affected the human most, the manner of the conversation changed from demons who trusted one another. To a King believing that his servant dared to deceive. The same King who has his hand surprisingly close to the human's vitals.
"What good have you received from this human for you to begin fooling your own master?" Once again, Kokushibou was left with no answer, his mind was filled with excuses after excuses. Muzan knows he's trying to find an excuse. "Kokushibou." Almost at the end of his patience, he would only accept the truth to be the next thing to come out of his mouth.
"There is no reason for you to spend your time tracking a human. If it was truly a potential you've spoken of, you could've turned him into a demon without having to wait." And there was no reason to hide anything from him. Centuries of trust and he threw it away, for a human? "Yet, you spared him. Has this truly what's becoming of my Upper Moon? Something soft?" He walked away from the human, his hand instead digging at the lowered demon's head. Clawing to find his own answers. A single thought was formed.
'Boredom.'
Muzan could've laughed. To find that the demon who he considered resembled him most had the same defects as the others. He did not find this amusing. He had only heard the metaphor of a heart falling into the stomach in a novel he started reading out of the same force that is boredom. Is that it? Would he eventually lose all the demons he painstakingly wasted his blood on? An eternity where he wouldn't be able to share with anyone, or perhaps he too will ultimately succumb.
"You're pathetic." Despite himself, he continued searching. He had not understood how this ties into the human. Perhaps there was something he could do to counter such problems.
He witnessed how Kokushibou first found the boy. A group of demon slayers far too weak and far too inexperienced was put together to fight him. They had no chance of winning. Somehow the boy stood out from the rest, whilst a single one of them split their bodies in parts so gruesomely, the boy was fast enough to block the attack, shattering his blade in the process, and he took his chance to flee. The sun is always there to be their one true obstacle prevent him from pursuing the boy.
It was a mere coincidence that he was able to watch the boy become the sole survivor. His method was flawed, a shameful way to keep on living. But he could see the vision, barely anyone could avoid let alone parry his attacks. And the young swordsman was not a Hashira. He has yet to be consumed by their way of thinking.
"It is… truly potential." Kokushibou dared to speak again. Fighting the pain from the claw so deeply rooted in his head. "I believe… he would have the potential to… please you." He could see himself in that child. Should Kokushibou truly fall, be it by a demon slayer blade or some other unexpected occurrence, he had always been a man obsessed with legacy. And if his blade was picked up by someone else. His master wouldn't need to miss his presence.
"Quiet." Miss? What would a King like him lack from a subordinate who thought too highly of himself? It's true he had reduced the assignments, he'd usually give one right after Kokushibou finished the last. Yes, more of their encounter was elongated and Muzan does consider Kokushibou and the person he most relished their conversation with. Even if there were none, Kokushibou was only there for the cold yet calming atmosphere he brought.
"For a silent man, you sure have your ways with words." He retracted his hand and placed it to lift the chin of the man before him. "Know your place. Kokushibou. Don't think that just because you're higher ranked you are more significant than the other little pests behind you." In the moment when he'd expected to see a hint of apprehension. Kokushibou seemed not to have listened.
"I insist." Was the only two words he had to say. He knew Muzan was always monitoring his mind, and he enjoyed the practice as it made expressing himself, something he was not experienced in, easy. "Shut up." Of course, Kokushibou hadn't said anything but it was the continued stream of ideals and thoughts. None that Muzan hadn't heard before.
He was the centre of the swordsman's world. He's the centre of every demon's world. His will is the reason for existence. Kokushibou, he had always been the exception hasn't he? Muzan wasn't above praise, praises he accepted are only those given to the people he considers worthy. He is amongst those people, his thoughts are a string of poems and songs. Compliments that should've bored him about four hundred years ago.
It's all because Kokushibou is all talk with no bite. Muzan is the one to be chased. To be desired. He shouldn't have been the one waiting for Kokushibou to finally act on his feelings. It's frustrating, how did they go on like this for so long? How dare he make him wait this long? "I will bring you proof... If you spare him." Heights and limits he promised, but his endurance in playing this game had also reach it's limits. "Where did you find the guts to speak against your King?" Last he checked Kokushibou is the type to suppress his opinion.
"Forgive me-" He spoke once more. Where had he gone wrong in teaching Kokushibou what his authority was against him, a demon who disobeyed him twice deserved a vile punishment. That's why, he yanked the hair of the arrogant demon by his other hand, the finger below his chin became a hand crushing his neck. He dived in to catch the unruly tongue and bit it off of its owner. Blood gushing out of his mouth, injuries he knows will get worse if he heals them without permission.
So Kokushibou sat there. Obidient as he's supposed to be. Ignoring the blood pooling in his throat and spilling by his lips. "Have I permitted you to speak?" His eyes narrow, daring that same fit of determination to come out again. Though he knows it won't, because his obedient shadow will stay as it is. A shadow, never moving unless he-
Despite the hands that were supposed to hold him down, Kokushibou pushed through. Transferring the blood from mouth to mouth. Though their blood contents were mostly the same Muzan could tell Kokushibou's was much sweeter. After chugging down the blood that had invaded his mouth, something else came with it.
Kokushibou slyly explores his mouth, licking the roof of his mouth, the sides, the teeth, Muzan couldn't stand to be outdone like this, he too uses his tongue to suppress his opponents, biting that same tongue again, but it doesn't take more than a millisecond to regrow before continuing his attack. "Hah- ha…" Both of their breaths are heavy. If it hadn't been for Muzan forcefully blocking his mouth with his hand, Kokushibou would've continued his onslaught.
"What… What are you doing!?" By now he expected the rationale of his Upper Moon to return. To go back to bowing and apologising, instead- Kokushibou began liking the inside of his hand. Slowly, tenderly. "Stop it!" He pulled his hand away, a string of saliva still latched onto his skin. "You- You!" Stop was the last thing he did, Kokushibou was even brave enough to stand up, towering over him and trying again.
They both end up on the floor. Kokushibou's hands rest at the sides of his master's face, the scene of him being overthrown by a demon he created himself was humiliating. It doesn't help that in this position, the distance between him and Kokushibou is looking down at him. His eyes spoke something he couldn't understand even if it's six of them expressing the same thing.
His soft red hair fell off his shoulder trickling down and falling gracefully on his face. Kokushibou doesn't mind brushing it off, but after touching his cheeks, he refused to remove his hand. Muzan may have short-circuited for a while, but his surprise shouldn't be blamed. A grin appeared so smoothly as Kokushibou narrowed his eyes and tilted slightly from his transgressions. "I won." He stated.
Capturing that boy could be considered one of his best decisions. "Even a prideful swordsman like you is still filled with lust. Still, you are as desperate as a human." He reaches upward, cupping the other side of Kokushibou's face. The face of a servant so hungry for his master. "You should be punished for this." Trying to get less torment to suffer, Kokushibou doesn't utter a word.
"Nothing to say?" On the outskirts, Nakime strummed her biwa again, accomplishing the order Muzan had given. The room shifted. They were on the floor of his chambers. A bed to their left and no one to disturb them. Kokushibou was pushed back by the hand returning to choke him, pinning him to the bedside. "By the end of this, I will remind you of the lesson you seemingly forgot." He closed in on their distance, his lips almost touching the swordsman's ear.
"And perhaps." Kokushibou felt a shiver run through his spine, when his ear was given attention by his Master, the sound of the wetness intensified. "Based on your performance now, I'll decide whether you get to keep that pet of yours."
Muzan walked through the corridor of the infinity castle, and even demons who were only lucky enough to catch a sight of him could tell that he was content with something. Enough that he's willing to walk back to his office without issuing an order to Nakime. He recalled the human was still there.
"Suppose you will be staying longer." Which is the best-case scenario for them as next to it was death. A change of plans was needed. He was hoping Kokushibou would thank him for letting him keep the boy, but the idea of him fighting to keep the boy alive was enticing. He wasn't fighting for Muzan's attention, which could be a bit of a disappointment. But he'll make do with what he can get from that cold-blooded samurai.
For his own amusement, and for protection, he granted him a room near his chambers as no stray demon was allowed to be near. It wouldn't be hard for a newborn demon to take a bite off a defenceless slayer.. Though before all that he would like to see the face that intrigued Kokushibou more clearly. Since covers and gags could've easily been what Kokushibou required of him.
With the blinds put away, a pair of terrified green eyes looked back at him. Tears were already forming, and he wondered how old the boy was, and there was nothing wrong with asking. The boy immediately used his throat to breathe once it was allowed, his focus still given to the demon who captured him. "What's your name, boy?"
The slayer looked away, hesitating for a while, but fear came over him as a claw scratched the surface of his neck. "It-It's Kaigaku. My…name is… Kaigaku." There is information about this boy that even Kokushibou didn't know, he's sure he'll be pleased when he can easily give it to him. All his sweet Upper Moon had to do, was ask.