The world around Tanjiro slowed down. He stared up at the back of the single Hashira who hated him and everything he stood for more than anything else. And yet, this man had stepped between him and Kokushibo… That would be a death sentence for anyone else save maybe Muzan himself and everyone there knew it. And yet, the Wind Pillar had done so willingly.

"Shinazugawa-san…" he whispered, almost not believing it.

"Hurry up and regenerate," the older Hashira said over his shoulder. Then he paused before speaking again through his teeth. "Sun Pillar."

Tanjiro's breath caught in his throat and he swore he almost felt tears coming to his eyes. That could also be from the pain of losing and trying to regrow limbs… but he doubted it. Still, asmuch as he welcomed the new acknowledgment, this was not a good situation. He hadn't slept enough in recent days and he was hungry and tired and his limbs weren't regrowing as fast as normal, which was still several seconds slower than most of the Waxing moons…

And yet, he couldn't let Shinazugawa down.

Gritting his teeth, he focused on his arm and legs, demanding they grow back and redirecting all his energy to that cause. The strange bubbling that tended to happen whenever he lost limbs grew faster and farther.

"I was going to kill you later," he heard Kokushibo say calmly, as if commenting on the weather. "But if you insist on now, then so be it."

"Bring it, monster!" Shinazugawa yelled, then launched himself forward. "First Form: Dust Whirlwind Cutter!"

The Wind Pillar was by no means a weak pillar. He had earned his title and Tanjiro would certainly count him as one of the stronger pillars in the Corps. But he was up against Kokushibo… Waxing One.

And Waxing One would have little problem overcoming any obstacle between himself and Tanjiro.

He dodged the many cuts sent at him by the older Hashira and suddenly stood over Tanjiro, blade ready to cut his head off.

He didn't think he could survive that…

And he did not want to go through all of this again!

Not again

A cry escaped his throat as he raised his blade, trying to brace it with what had grown of his arm. It deflected that swing but Kokushibo went in for another blow. He wouldn't be able to block or dodge this one… maybe he could move so it hit his torso instead?

Behind the older demon, he heard Shinazugawa shriek in frustration and anger. The Pillar rushed forward, and even in that moment he must have pushed himself beyond his limits, because Tanjiro could see the windmill-like mark appear on his face. The time traveler's eyebrows approached his hairline.

However, Shinazugawa shouldn't have screamed. Instead of lopping off Tanjiro's head, Kokushibo turned and swung his ridiculous sword at the Wind Pillar. Shinazugawa had already launched his attack, though and while Kokushibo changed his attack into a block, one of the wind blades sliced right through the demon's arm.

The white-haired man grinned like a maniac… but he couldn't stop himself, and Kokushibo was already swinging again, a cry of rage shooting from his parted lips.

Tanjiro felt his breath stop…

No…

No, no, no, No, NO! They needed him! And he'd been with Tanjiro… Tanjiro should have protected him!

"NO!" he yelled out, long and loud, not sure of what else he could say or do.

The swing connected… and kept going.

The man's torso fell to the ground, followed by his legs… completely separate of each other. Above him, Kokushibo stumbled in surprise. Then the scent hit Tanjiro and it was all he could do to not attack the merechi himself.

No, his arms… he had to regrow his arms…

At least it took Kokushibo several seconds to overcome the smell as well. He grit his own teeth and began grumbling about upstarts who didn't know their place as he focused on regrowing his own limb. He'd had far more practice than Tanjiro, it seemed, because it grew back almost instantly. He checked it, wiggling his fingers, as if he had all the time in the world.

Meanwhile, Shinazugawa's wide eyes softened and he smiled sadly. "Sorry… Genya," he whispered.

And that was just too much for Tanjiro. He could not go back and tell Genya his brother had died… protecting him!

And that was when the time traveler realized his blood literally littered the entire clearing.

He had enough energy for that, at least.

"Palm Fire Explosion!" he yelled, willing the entire area to light up in red and pink fire.

It caught Kokushibo off guard and for the first time, Tanjiro heard him scream in pain. It wasn't a pleasant sound.

Burn out the demon, he thought and pushed all but the barest of his energy and will into that single thought alone. The rest he shunted into finishing growing his limbs.

Unlike the other demons Tanjiro had caught in his flames, Kokushibo swung his sword madly in an attempt to stop the burning. The younger demon had to clumsily dodge several swings before he could once again get to his feet.

His bare feet… but he could handle it.

He was just thankful the Waxing First hadn't thought to use his own Blood Art just yet.

Tanjiro sheathed his blade and scrambled towards Sanemi's body just as his limbs finished growing (to slow, too slow, even for him!), reaching their full size. He reached down for the dying man but paused. He could take care of Kokushibo now, or he could get Shinazugawa out of here to die peacefully…

Right about then, Kokushibo began to use his Demon Blood Art, though, and Tanjiro wasn't sure he could finish off the Waxing Moon yet…

Who was he kidding? He'd already made his choice.

Scooping both halves of Shinazugawa up, Tanjiro turned and took off, racing as fast as he could out of the forest while keeping the flames up behind him.

Kokushibo wouldn't let them escape if he let down on that.

Surprised, the Wind Pillar looked up. It was a miracle he was still alive. He must be using his breath forms to do so.

"Hang in there, Shinazugawa-san," he said, focusing on running away instead of the scent of the absolutely delicious smelling blood.

The Wind Pillar just laughed as Tanjiro raced through the trees.

"You really are on our side, aren't you."

Tanjiro didn't answer except to nod, eyes focused ahead of him.

"Heh," the white-haired man chuckled. Then he sighed. "Say goodbye to Genya, for me, eh? Tell him to stop being an idiot and go find a good woman to settle down with."

"You can tell him yourself," Tanjiro said, although it was more out of reaction than anything. They passed through the Wisteria trees (he ignored the stinging on his skin and in his lungs) and into the wilderness outside of it. Tanjiro wasn't even sure which way he was running. He just wanted to get away from Kokushibo.

At least he had his answer about whether he deserved the 'Waxing Zero' position or not.

"You can't save me, kid," Shinazugawa said, words slurred.

Tanjiro grit his teeth because he wanted to save him. He wasn't sure what would happen if Sanemi wasn't there with them at the end, not to mention the man had been killed protecting him…

Wait…

He froze mid step, eyes wide.

He could save Shinazugawa.

But… would the man want it?

"I… can save you," he whispered.

Shinazugawa must have reached his limit because he didn't respond. His breathing had slowed.

Tanjiro panicked.

"Shinazugawa, I can save you! But…"

No response. His window for acting was closing.

Tanjiro grit his teeth, realizing that this would bring very, very harsh scrutiny on him… but he couldn't just let the Wind Pillar die…

Decision made, he took a deep breath and bit his finger.

"One day, I hope you can forgive me," he whispered and then plunged his hand into Shinazugawa's chest.

xXx

Sanemi didn't expect to wake again, but his eyes opened… to nothing but darkness. Before, he'd been slowly losing feeling, hands and arms and even his chest and stomach growing numb. Now, his entire body felt as if it were on fire, seizing up to a point where he could barely move and he couldn't even scream it out. Every muscle tensed and he couldn't relax them if he wanted to.

If this was Hell, it sure lived up to its reputation.

Eventually, he managed to shriek out an unholy scream of pure agony… or he would have had someone not put something over his mouth. He still tried, moving instinctively to hopefully alleviate the utter pain that took over his mind. He couldn't think of anything else.

He heard something outside of him but couldn't make out who or what it was through the agony. He arched his back, scrabbled at the ground, clutching at the dirt before his hands would spasm and he'd let it go, only to tense and curl them up again. The bones were moving – changing… and he couldn't stop them!

What was happening to him?!

He wished with all his heart that the pain would. Just. Stop.

He would do anything!

Then he felt something soft in his hand, squeezing it. It took him a moment to register, but then he squeezed back, grateful for any comfort, as small as it was. He felt a snap as whatever was holding his hand broke, but he couldn't make himself let go…

It hurt… so much…

He heard a hiss of pain that wasn't his, but that was all he could process before the burning overtook his senses again.

And then the hunger started.

He tried to gasp, but whatever was over his mouth stopped him from doing so. The world around him began to… grow brighter? No… it was more like he could just see better and he finally made out his companion…

The demon brat, looking down on him with such a concerned expression…

Oh, right… he was dying…

But should it feel this bad? His body wracked in pain and his stomach feeling like it wanted to gnaw on itself.

There was something to that, but… he couldn't make out what. His thoughts were so blurry, like he was trying to think through a fog. He could remember everything if he tried but…

He didn't want to try right now.

He just…

Wanted.

To.

EAT.

He couldn't stop himself from lashing out and the kid backed away, jumping to gain distance as he watched… wait, what was his name again?

Sanemi.

His name was Sanemi.

Shinazugawa Sanemi.

"Shinazugawa-san," the boy said cautiously, glowing red eyes fixed on him warily.

He liked that cautious look in his eye… but it also felt wrong…

And there was a scent… such a good scent… it made his mouth water. It made it hard to think.

"We have to go before Kokushibo catches up," the boy said, still looking at Sanemi like he was a wild animal…

No, he didn't like that look… he hated that look. Too many people gave him that look.

He found himself snarling angrily, showing his teeth at the boy. He wanted to stay… he wanted to find the source of that scent!

Oh… it was on the plants around him… on the forest floor.

That sucked. He bent down to lick it…

It smelled so good…

Then, to his surprise, the boy snarled back and suddenly Sanemi knew, this was not someone to rebel against. He didn't know how he knew, but every fiber of his body was telling him to obey.

He'd already backed down before he could register it, holding his head in his hands. Why couldn't he think?!

"Shinazugawa," the boy said in a commanding voice (with just the hint of underlying fear, but it wasn't of Sanemi). "You will follow me. Now."

Sanemi hated it, but he nodded his head quickly. The boy bit his lip, looking pained and unsure, but then he took a deep breath and leapt into the tree tops.

Follow him! Something whispered inside of him… that same thing he couldn't really seem to fight right now. So he did as it said.

He leapt into the treetops and followed his… Master? Yes. That sounded right…

And wrong. So wrong…

But he'd figure that out later… after he'd gotten something to eat. He really hoped they could stop and hunt soon… hunt for food… he needed food…

xXx

Tanjiro hadn't known what to expect, really. He'd thought that turning Shinazugawa-san like that would have simply saved his life. He'd be the same explosive jerk he'd always been and that would be that.

But he'd gotten a demon.

It made Tanjiro sick to know that he'd been responsible for that. Even now, he could feel Shinazugawa's base instincts had taken over. It was all he could do to command his fellow Pillar to follow him. And it wasn't helping his own hunger.

At least they'd gotten away from what was left of the merechi blood. Still, he knew they were leaving a scent and they would have to wash soon.

Thankfully Sanemi looked pretty normal… no strange appendages or skin coloring besides a mark on his cheek – his Demon Slayer mark, not a demonic mark – although his tongue…

He glanced behind him to see said tongue lash out of the Wind Pillar's mouth, almost like another appendage, and winced. He looked ahead of them again, bouncing off of and through the tree branches as fast as he could without leaving Shinazugawa behind.

Then they came across a stream and he immediately stopped, dropping onto the bank and looking around. He couldn't see or sense anything other than the two of them. Then he looked over at Shinazugawa who had landed in a crouch. Tanjiro had put the man's legs near his body after he'd pumped a small amount of blood into Shinazugawa, hoping that they would reconnect… and they had. Which was very good as the last thing he wanted was to be running around with a half-naked (literally) demon at his beck and call.

That didn't clean the blood on those clothes. They had left a trail, albeit a faint one, but…

It didn't help that Shinazugawa was chewing on the blood-soaked parts of his shirt, looking extremely disappointed.

Yeah, he wouldn't' get much from that, merechi blood or not.

Tanjiro sighed. "Come on," he said, gesturing to the stream. "We need to wash up. We're lucky he isn't on our trail yet."

For several seconds, the newly turned demon just stared at him. Then, to the time-traveler's disbelief and dismay, he sat down, folded his arms and pouted.

Tanjiro blinked at him, then sighed again. "Don't make me make you," he said – almost pleading. He hated that he even could make his (and he still hated thinking of them as his) demons do things against their will.

Shinazugawa winced at that, and then, slowly, got to his feet. He crawled on all fours to the stream, hands completely unfazed by any sharp rocks he may or may not have run into, and frowned at the water. Then he looked back up at Tanjiro, almost as if to plead.

"Go on," he said as he would talk to one of his younger siblings.

The Wind Pillar frowned mutinously, but got into the water and began washing the blood out of his shirt fairly competently. Pinching the bridge of his nose, Tanjiro sent a prayer to his father that he'd help him with patience and then joined the other demon in the river, washing what he could.

It was really a shame he'd lost his shoes. He'd just broken them in.

But they'd gotten away from Kokushibo. That was the most important thing.

That and figuring out how to beat him next time.

He stood straight and looked around, throwing his senses out, but again, couldn't find anything. Had Kokushibo not even tried to follow them?

Had his fire been that detrimental to him?

One could only hope, he supposed.

He went back to washing the blood out of his pants, shirt and Haori. Hmm, he'd have to get a new one of those too. Pity.

And Shinobu was supposed to meet them…

He suddenly groaned. If Shinobu hadn't left the Ubuyashiki estate today, she would leave tomorrow. They had to get to the estate and intercept her…

He glanced at Shinazugawa who had just sat down in the water and was now staring angrily at him (at least some things never changed).

He'd have to intercept her and hope she didn't kill him on the spot for this.

He groaned again and sat down in the river too.

He'd find positivity in the situation in a moment. For now he needed to rest.

xXx

Muzan had known Kokushibo for over four hundred years. He knew the man to be aloof, cool and in control of himself.

That was why the person who fell through Nakime's door after screaming out her name downright shocked him for the first time in centuries. He'd seen the man angry, hungry, frustrated and determined. He'd never seen Kokushibo lose control like this, when hunger had nothing to do with it. Even still falling and on fire, he'd been shouting, cursing and screaming; raving to a point of madness, his eyes fixed on the closing door above him as the flames on his clothing and body slowly faded away.

Muzan knew that fire.

He grit his teeth and walked over to see his snarling Waxing Moon, ready to lash out at anyone.

The Demon King concentrated on his arms, growing them and shooting them out, pinning the Waxing Moon to the ground.

"You lost?!" he hissed.

Kokushibo wrestled against his bonds angrily, but at least spoke somewhat coherently. "He tricked me! The coward tricked me and ran away! I'll kill him! I'll destroy him! I'll—"

Muzan slapped an extra appendage he'd just grown against Kokushibo's mouth.

"Be silent," he hissed.

Fortunately, Kokushibo knew enough, even in his maddened state, to back down. He still didn't look like he could speak without screaming.

Then Muzan decided to forgo any further madness by going directly into his demon's mind. It only took moments to do so. He watched the battle from Kokushibo's eyes and frowned. The boy had put up a spectacular fight… for a Waxing Moon. But, in the end…

Muzan finished the scene and smiled. The boy was strong, but nowhere near strong enough to defeat him. The boy had lost to his Waxing One… There was no way he'd be a threat to Muzan. Not a true one.

And they'd gotten rid of one more Pillar in the process. Retribution. A Waxing Moon for a Pillar. Not nearly a fair enough trade, but one he could live with.

Now, if only…

Hmm… Kokushibo was off balance and… he did seem weaker. He didn't have as much of Muzan's cells inside of him as he'd had before. So the boy could literally burn the cells out of a demon. That was a problem… although it didn't seem like it could really do much harm in the long run. Not if they stopped this problem as soon as they could.

"This is the first time in four hundred years you have truly disappointed me," he said. "And I do not want to spend the time or effort replacing you. As such," the appendage covering his demon's mouth snapped down into Kokushibo's throat. Then the Progenitor of Demons began to pump more blood into his Waxing Moon.

He loved the look of utter ecstasy on their faces when he gave of his blood. It had been a while since he'd seen Kokushibo like this and he'd almost forgotten… He loved inflicting pain, and he loved inflicting this. It hurt them, so not pleasure, per se (at least not in the traditional sense), but he knew they could sense their own power growing.

At least the Kizuki had calmed down.

Muzan let him go and he fell to the floor, twitching.

That felt good too, seeing such a stoic and controlled man sprawled in front of him, trying to rise to even his elbows and only barely succeeding.

"I expect better from you next time," the Demon King whispered down to him.

"Yes, Muzan-sama," Kokushibo said. He'd managed to get to his knees, but instead of trying to regain his feet, he turned and bowed before his kami, as he should.

Yet another reason why he liked Kokushibo so much.

He'd really hate to have to write him off.

"Good," he said. Then he turned around towards where he could sense Nakime and called out to her. "Call the other Waxing Moons. We have updates."

The woman with the kanji for Waxing Three in her eye, acknowledged him with a twang of her biwa.

Muzan turned to walk into the room he would meet the other Waxing Moons in, feeling both more wary and more sure of where he stood in his plans and where Kamado Tanjiro would fit into them.

He'd have to do some new recruiting to take care of the lower ranked slayers, but he could move forward with his plans of destroying the Demon Slayer Corps altogether very, very soon.

xXx

AN: Yup, so a lot of people guessed it. I had many reasons for doing this, so I hope you like it. :)

Thanks to TimeLordTim, Quathis and Found for their help on this! Much luv!

Discord: discord. gg/xDDz3gqWfy (no spaces)