Chapter Text
Tanjiro hummed next to Kyojuro , before gesturing to Nezuko. In a wash of purple flames, the pair appeared in a dark forest, behind the silhouette of three figures. Kyojuro looked on as the smallest of the group span instantly, his eyes widening at the sight of the two sword wielding demons.
He smiled then, which surprised Kyojuro. After all, it wasn’t many people who would be happy upon seeing a rival Demon King appear behind them, or that he had brought his Waxing Four with him to confront them. Then, he considered what Gyomei had told the pair about this specific demon, and the behaviour seemed to make a little more sense. This Akaza was a strange character at the best of times, and he had shown a love of combat against Gyomei. Granted, he had fled from the fight while Gyomei tried to convince his kid to let them go, but that had also been in the face of the sunrise.
Tanjiro stepped forward. “Good evening Akaza. I am Tanjiro - another progenitor - and I was wondering if we could have a conversation.”
“What would you want to talk about?”
Tanjiro smiled, and the light cast by his cloak glowed a little brighter. A sign he had brought forth his mark and was displaying his true power. “I need you to stop killing humans, and your going to release your Kizuki’s free will.”
Akaza laughed. “Why don’t we fight for the right for you to hand down such proclamations?”
He didn’t pause for Tanjiro’s answer, instead bringing forth a glowing blue snowflake. Kyojuro recognised the activation of a powerful blood demon art, and drew his blade against the threat that was so implicit in the action.
Tanjiro, however, only shook his head. “I am not the one who you will be fighting today, Akaza. Not when you struggled so against Gyomei. It just wouldn’t be sporting of me.” He turned, then, to Kyojuro, who’s eyes widened in surprise. “Instead, I think it would do you some good to fight against my Waxing Four, Kyojuro.”
“You are going to regret that.” Akaza wasn’t amused by Tanjiro’s seeming games, and lunged forward with tremendous speed.
Moving with the grace of a dodging serpent, Tanjiro slid through the barrage of punches without one ever even coming close to landing. The exchange lasted for several seconds, as Tanjiro dodged around and ducked through openings, completely slipping Akaza’s guard.
Moments later, Kyojuro saw the telltale tense of Tanjiro wielding a breath. Akaza flew back, clutching at a gaping hole Tanjiro had punched clear into his side. Blood flowed out in a rush, but only for a moment until Akaza healed the wound. The speed of regeneration from such a grievous wound was incredible, but Kyojuro didn’t let it unnerve him. Instead, he sank into his breathing and stepped forward, sensing his time was nearing.
The two demons who had been standing to either side of Akaza must have felt the same moment of momentum, as they both shot forward. Their steps seemed to fall in terrifying tandem, and the overlap of their fighting spirit created the impression of a tsunami striking the ground.
Tanjiro stepped in to intercept them, while Akaza looked to Kyojuro. “What arrogance, to send a mere Waxing Moon against me!”
“I wouldn’t call it arrogance just yet.”
Akaza flew forward, battering his fists against Kyojuro’s defence. “Sending a swordsman who hasn’t even managed to unlock their mark. Your weakness sickens me.”
“You have yet to even manage a breath style - I wouldn’t be so anxious for me to develop a mark.” The third form bit forward, catching in the flesh above Akaza’s shoulder. Drawing back, Kyojuro was impressed at how quickly the deep gash changed back into smooth skin, only leaving behind droplets of blood.
The return strikes struck with the force of hammers, each and every one. Sliding backwards through the ground, Kyojuro bent all his will to parrying the blades. In this, he wanted to imitate Tanjiro - fight by the same rules his lord always did. Any attack let through was a failure, and shouldn’t be regenerated until the end of a battle.
After pushing Kyojuro back, Akaza grinned. “I think you need to fear my technique far more than I need to fear your breath!” With that, he smashed his fist down into the ground, causing the entire area to destabilise.
In the moments it took for Kyojuro to regain his footing, Akaza closed the gap. Out of position and blindsided, Kyojuro sustained his first wounds of the fight. The fists took chunks out of his skin, causing the molten blood that ran through him to fall to the ground. Akaza hissed in pain at the few droplets that landed on his skin.
“Why don’t you regenerate?”
“It would be an insult to those I fight to not allow their wounds to have meaning.” That was what Tanjiro always said when pressed on the answer.
Akaza scoffed. “How stupid. Use everything at your disposal: other people use their mind and their tricks to win, demons can regenerate. In true combat,” he moved again, coming down with a tremendous axe kick, “you don’t get the luxury of choosing what you can and can’t fight using!”
Kyojuro blocked the blow, before slashing down at Akaza’s back foot in a blaze of flames. “So you would use both your blood demon art and your regeneration against a Demon Slayer, who has neither?”
“Yes. Just as they will use poison, traps, and their breath against me.” While speaking he jumped up, and landed on the back end of Kyojuro’s blade, rocketing forward inside his guard. The blow skimmed past his head, and took out his eye with the force of it. “It would be an insult to fight with any less!”
In a blinding flash, the blade reversed and flashed upwards. It sliced through the air, roaring with the fire of Kyojuro’s fighting spirit, but Akaza back flipped away.
He pointed then, at Kyojuro. “You are denying what it means to have become a demon.”
They reengaged, and a dozen cuts and parries were exchange inside a handful of moments. “How could I deny what it means to be a demon. It permeates everything that I am, now.” Kyojuro replied.
Akaza laughed, before bringing down a damning kick to the inside of Kyojuro’s knee. The bone shattered under the force, and smashed him into the ground. “If you were still a demon slayer, I would have commended you for the fight. But for Waxing Moon? Pathetic.”
The next kick carved in half of Kyojuro’s face, smashing him backwards onto his back. He couldn’t speak now, as his mouth had been shattered by the force of Akaza’s assault.
“You disgrace your creator by spitting on the gifts of strength he gave you.” Akaza seemed furious - a far cry from the figure Gyomei had spoken off. “You won’t let yourself enjoy the fighting, even though it is what you are made for now. Your still weak!”
Part of Kyojuro wanted to reject the idea. He loved his creator, and would do anything in service to him. But something inside of him told him not to discount his enemies advice. Maybe part of him was still consumed with human doubt about fighting, and hadn’t accepted the new instincts that he had gained.
A vision of the past overlaid Kyojuro’s vision.
Tanjiro had come to Kyojuro early into the night, finding him practising his flame breathing. Every form flowed from one to the other with the technical perfection of hours and hour of repetition. It was clear to both that these motions were the result of hours and hours of practice, drilling them to perfection. But the motions didn’t feel right to Tanjiro, in a way he hadn’t been able to explain to Kyojuro.
He’d confessed, when talking about it, that Kyojuro was a different case to most of his pupils. Neither Obanai or Mitsuri had been suited to any of the base breath styles. Instead, teaching them had been placing them in contact with their fighting spirit and refining what their instincts told them to do. Both styles were deeply interwoven into the Blood Demon arts they used, and didn’t vary much at all.
Gyomei, by comparison, had taken to Stone Breathing like a duck to water. Once he had grasped how to move, and how to use his new senses, he had become a force on nature all on its own. The unlocking of his Blood Demon art had just been the icing on the cake to cement his rank as Waxing One.
Kyojuro, however, had suffered a lifetime of training with the sword. From the moment he could walk, he had been taught footwork; from the day he had been able to grip a blade he had been taught how to slash and parry; from the moment he could understand what was being said he was taught how to breath. All of this had led to him being a tightly coiled weapon of destruction, with muscle memory so used to combat it knew very little else.
Tanjiro had decided, that day, to try and push Kyojuro to try and unlock his mark. He though, since all the others he had taught had unlocked it in bouts against him, that it might help him learn where he was going wrong if he had his own.
As such, the pair had squared off for hours. Each bout had lasted less time, with Tanjiro trying to goad Kyojuro into pushing past the limit. None of it had worked. Not even under a full barrage of the Thirtieth Form had he been able to reach the point of anger and focus needed to bring about the change.
The experience, however, of facing Tanjiro’s full powered Sun Breathing, had taken Kyojuro’s breath away. The strength and speed of each attack would have been enough to decapitate him instantly, if Tanjiro hadn’t been slowing himself and missing intentionally. While watching the Demon King move through the forms as easily as a eagle soars through the sky, a small, rebellious part of Kyojuro thought that because Tanjiro was going easy on him he would never be invested enough to reach the state needed. Maybe if he had been more willing to inflict the kind of pain his father had used, he might be able to force the mark.
Tanjiro had been cheerful though. He’d told Kyojuro, “I don’t think I’m the kind of opponent that will be able to push you to manifest your mark. Maybe you’ll find someone out there who will push you far enough that you can.”
He’d hugged Kyojuro then, which had been completely at odds to how he was used to his training ending. “I can feel your fighting spirit in every blow. There’s just some slight style tweaks, then it’ll be amazing. Just wait!”
Kyojuro opened his eyes again, and stared up at Akaza, with new found confidence. This wasn’t a state of affairs that could be allowed to continue.
Nearby, Tanjiro was duelling the two demons Akaza had brought with him.
The pair might be gifted, but they had a long way to go before they were able to challenge Tanjiro. The pair both moved with speed and grace that shouldn’t have been possible for such young demons. Their Water Breathing was equally as impressive, but it still had some of the rigidity of Kyojuro’s Flame Breathing. That must make it an artefact of being passed on from the Demon Slayers, rather than being taught by a Sun Breather directly.
Either way, after seeing these two gifted swordsmen struggle with the same issues as Kyojuro put his fears aside about it being his own poor teaching. Instead, he needed to teach him something that the Demon Slayers must be missing.
Ignorant of Tanjiro’s thoughts, the two demons moved together, much like the crest and trough of a wave. The red haired one was always moving forward, pushing forward with his water breathing. His motions seemed designed to force Tanjiro back, and cause a gap to appear that he could take advantage of. Meanwhile, the dark haired one seemed able to understand where Tanjiro was planning to strike and intercept him with well placed parries.
This was made far easier for the pair by the fact Tanjiro had sheathed his sword and was instead using a stick for a weapon. As such, he was unable to parry edge to edge, as the strikes were more than strong enough to cut clean through the twig, and was instead having to divert blows with sweeping parries against the sides of the blade.
It didn’t take long, even with this disadvantage, for Tanjiro to split the two up onto either side of him.
“Why don’t we start with some introductions?” The demon king tried to ask.
Neither replied, and instead rushed forward. Pushing slightly faster, Tanjiro danced between them. They would tire far before he would, and he needed to try and bring out something in the pair.
It wasn’t that he couldn’t do what he planned on them without something to grasp. Tanjiro was reasonably sure he could convert everything less than a Demon King with his blood at this point, and even a Demon King could be turned if it gave permission. He knew that from having to turn Nezuko. But if there was nothing of the people these two had been left inside of them, then forcing them to undergo another demonic transformation may not be fair. That kind of radical cellular change could be agonising for those who were deeply tied to their original progenitor, which these two seemed to be.
The only spark he had seen had been when he had pushed the peach haired one. His companion had pushed forward and used a style of Water Breathing he had never seen before, and nullified all the oncoming attacks with minimal effort. It had impressed Tanjiro to be honest.
He decided that would be the only way to test his theory. Dropping the stick and activating his mark, Tanjiro drew his katana into a clean downwards stroke against Sabito, now the two were opposite each other. Neither younger demon even had time to react to the instantaneous change, as the Demon King vanished from equidistant from each of them, to striking at Sabito with lethal intent.
The change was instant from both demons. Suddenly, the speed of both Tanjiro’s enemies increased exponentially. He could feel the foe behind him move with tremendous speed to try and intercept the strike, but all present knew it wouldn’t be fast enough to get there.
A cry of rage and loss echoed out. “Sabito!”
The blow stopped hairs width above Sabito’s shoulder, as Tanjiro smiled. “It’s a pleasure to meet you Sabito. Can you talk or is it just your friend that can?”
The demon snarled, and his blade moved in a way Tanjiro had never seen before. It took his breath away to see such an imaginative and resourceful use of Water Breathing, as the demon used what clearly had to be a new form. His fighting spirit coiled and seemed to drag Tanjiro forward with the force of it, into the jaws of seven perfect cuts.
Each one was parried, almost before the momentum of the strike could assert itself. The technique was good, and so was the wielder, but he wasn’t able to reach the heights needed to place Tanjiro in real danger. He turned, sensing the heavy footfalls of his other opponent. A brief glace showed Tanjiro all he needed to know - after all it wasn’t many demons who would reach the state needed to activate their mark when someone else was in trouble. It stained his skin, colouring large sections with its advent. Tanjiro kicked out backwards, and threw Sabito out of the battle.
He could feel the panting of the demon as he rushed forward, with his blade flashing in the washes of light from the battle going on next to them. Each one had gained tidal strength, hammering into parry after parry to push Tanjiro away from his fallen comrade.
“It’s alright, calm down. We can stop now, I won’t hurt you.” Tanjiro tried to calm the onrushing enemy, but a mad light had entered his eyes. Nothing short of hurting him would get him would get him to snap out of this rage.
Once the moment came, he didn’t hesitate. The demon swung just a little too hard, and as his blade bounced back with the force of impact against the parry, Tanjiro stabbed through. He pinned the demon to a tree through the meat of his left shoulder, before turning to catch the oncoming blow of the returned Sabito.
“You won’t hurt Giyu!” He howled, despite having his blade trapped in the fingers of Tanjiro’s hand. A similar mark to Giyu’s had appeared on his face, but the lines seemed sharper. Tanjiro could feel the hatred in his eyes.
“Rest easy. This won’t hurt too much.” Tanjiro punched out and delivered a payload of blood into Sabito’s chest, ending the struggle in a moment. The demon fell to the floor, gasping, as the chances started to take place.
Tanjiro turned and repeated the same motions to Giyu, before withdrawing his blade. The two were gifted, he had no doubt, but it would be a long time before they learnt enough to battle him properly like they had tried. Maybe in a few hundred years. He turned to watch Kyojuro, his Waxing Four, fight against Akaza. It would do wonders for him to face true battle again.
Kyojuro’s eyes narrowed, before he let his bodies natural rhythm reassert itself. The rush of flames glowed red hot atop his head, and his cloak reignited. In a moment, the grievous wounds healed over, and the temperature of the air began to increase.
Flames burst our from both his hands, and the flame held between the horns atop Kyojuro’s head blazed into a miniature sun. Even his blade caught alight, with orange flames flickering and burning all along the length.
“Do I look weak to you, Akaza?” He asked, pointing his blade directly at Akaza
The demon turned from where he had been stalking to attack Tanjiro. “Still asking questions without proving your worth. Maybe land some hits and I’ll take you more seriously.”
Kyojuro laughed, deep and loud. The sound resounded out into the darkness. “It will be my pleasure to educate you, Akaza!”
The following clash had both sides taking what should have been mortal injuries. In a flurry of cuts and parries, Kyojuro had to regenerate muscle, bones and organs from where he had missed attacks. But Akaza fared no better, and his regeneration was hampered by the flames that stuck in the wounds, continuing to burn even as Akaza healed from the actual cuts.
Of the two, however, Kyojuro was still suffering more. While Akaza had to content with fire burning through his regeneration, Kyojuro had never trained to regenerate fast. It wasn’t a skill he had ever judged he would need, and the focus needed to keep himself whole while still trying to parry and counter Akaza’s attacks was almost too much for him. Slowly he was being forced back, away from Tanjiro and the two younger demons.
But he was beginning to feel something. A fierce joy in the battle, as he was forced to fight at the upper limits of what he was capable of. The heart that he had judged so worthless after becoming a demon began to beat once more, slowly at first. Inside, he felt his body become hotter and hotter as the heart beat started to increase.
Each thrumming of blood pushed through his body made him faster. The air began to steam as the two fought, before Kyojuro managed to reverse the fight’s momentum. He felt something burn across his skin, and deeper, as he pushed forward with one final Rising Scorching Sun attack, the swept up and sliced through both of Akaza’s hands.
Flipping back away, Akaza looked to regard his opponent. He had sensed when the change had started inside of Kyojuro, and had revealed in the strength it gave him. The fight had grown more and more interesting the longer Waxing Four had fought. Now, he stood, resplendent in a cloak of flames and a flaming blade, preparing one final attack to prevent Akaza from interfering with his lord. The battle had even been enough to draw out this swordsman’s mark - an ability that genuinely placed the outcome of the battle into the balance.
The fierce joy of the confrontation mounted. “Let us give this last attack our all, Kyojuro!”
“Of course, Akaza. I would never dare do any less!” Kyojuro felt the same manic, gleeful joy that he thought Akaza must feel, and it rushed through his veins to propel him into greater heights.
The two concentrated on their techniques, preparing to unleash them will the full power they could drag from every cell in their bodies. Akaza adopted the stance needed for Destructive Death: Annihilation Type.
Kyojuro slid his front leg back, dropping into a bastardised running stance. He had never successfully used this technique, not even with all his fathers ‘training’ but something now told him he needed to let that go. The voice of his brother echoed, for just a moment.
“Your more than Father ever was, don’t let him define you!”
He spoke allowed as he began to move. “Flame Breathing, Esoteric Art, Ninth From: Rengoku!”
The world seemed to vanish under his feet as he flew forward in a billowing cloud of flame. The wash of heat enveloped both him, and Akaza, as the two combatants clashed in a titanic impact. The ground buckled under the force, being forced into the flames and charring as Kyojuro cut through Akaza’s first attack. He saw the demons eyes widen in shock as the blade reversed and cut through the other arm before it could impact. Then, with the last of the momentum, he pinned his blade through Akaza’s body, driving them both into the ground.
It ended with Kyojuro locking Akaza to the ground, with the blade pressed through his sternum to keep him still. The only noise that filled the air was the two’s heavy breathing, as Akaza looked up into Kyojuro’s eyes. He smiled, before starting to fight to try and free himself.
Keeping him pinned wasn’t easy, but Kyojuro could feel Tanjiro approaching from behind him. He could also see Akaza’s eyes lock onto where Tanjiro must be standing.
“You can let him up now, Kyojuro. Good job.”
Something lit aflame inside Kyojuro’s breast at that.
Tanjiro turned to Akaza, who had managed to claw his way back up into a fighting crouch. “Will you allow me to turn you into one of my demons?”
Akaza narrowed his eyes in suspicion. “You aren't going to kill me?”
“Not unless you make me.”
“Why?”
“Why do you believe I should kill you?”
“That’s a stupid question. You proved stronger, therefor you kill me.”
“I don’t know if I agree with that. It certainly doesn't follow my morals.”
Akaza scoffed. “Any other morals are useless and weak.”
Tanjiro smiled. “They didn’t seem weak when I defeated you. They didn’t seem weak when Kyojuro defeated you.”
“You will never climb as high as you could if you cling to those ideals.”
Tanjiro stepped in, his arm extended. “Does that mean you won’t allow me to?”
“Not until you answer my question. Why would you want to.”
Tanjiro paused, leaving his hand outstretched to Akaza. “Muzan turned you into a monster, and stole your memories from you. However, from what I saw from your two Kizuki, you don’t seem all that monstrous.”
The disbelief was etched into Akaza’s face. “I’ve killed hundreds of people.”
“Defenceless innocents? I’m not so sure.”
“When I served Muzan…”
Tanjiro’s eyes darkened. “Those actions are his actions. No one can resist him.”
“What will the change entail?”
“A few droplets of blood. It should fight off whatever is left of Muzan in your system. It might even return your memories.”
Akaza looked down, before reaching out. “You will train me to make me stronger.”
The palms clasped, and blood flowed from Tanjiro’s hand to inside Akaza’s blood stream. “I’m sure that can be arranged.