*Alternate Ending instead of chapter 85 - may also want to read Reoccurring Sunrise before this as well.

xXx

Tomioka Giyuu raced over the mountain, having left behind the village he'd been assigned to. It had been wiped out, left as a ghost town to be reclaimed by the nature surrounding it. It hadn't been completely empty when he'd arrived, but he'd had to kill every individual remaining alive as they'd all been demons, which meant he was chasing a Waxing Moon or… Kibutsuji Muzan himself. He had to get to the next town by morning, to try and warn them or defend them or save at least some of them… curse his inability to be as strong as he needed to be. Curse his inability to be enough.

The clouds over the mountain hung heavy with snow, but Giyuu pushed on. He'd been traveling all day already, but he couldn't stop. If he ran straight through the night he might make it. But he had to push harder, farther, faster…

He had to—

An enormous crash forced Giyuu to stop in his tracks. What? That had come from just ahead and to the right… towards the pass he was heading to. What had that… could that be the demon? Had they run into another Hashira? A good one? Like Shinazugawa? But wasn't he supposed to be farther south? Part of why Giyuu had been sent on this mission was because he was used to training and working in the mountains.

When he heard nothing else for a couple of seconds, he went to push off and rush ahead again, but before he could the mountain started shaking.

No, seriously, what?!

He forced himself to run again as the trembling subsided, his constant concentration pushing his body so the world around him sped by in a blur. Another deafening clash sounded. If he didn't know any better, he'd think mountains themselves were fighting. Thunder directly overhead didn't sound that loud. Would he have to protect his ears? If that continued, probably…

And then someone screamed. The echo reverberated around him, sending shivers down his spine. Giyuu didn't think he'd ever heard anyone sound that… terrified and simultaneously angry before. His stomach dropped to his knees and he grit his teeth. No, no, no, nononono! He was too late. Again. (Story of his entire career – of his life.)

But he had to keep going. He had to try. Sabito would have. He ignored the voice in the back of his head saying Sabito would have been fast enough to begin with. He agreed with it, but that knowledge was useless at the moment.

So he ran on, despite the mountain falling into an even deeper silence than it had before. Snow drifted down around him, muting the atmosphere, but he still strained his ears for something. Anything. He heard nothing.

He continued in the direction he'd heard the noise, though, an hours later, he finally stumbled onto what he knew had to be the aftermath. A crater the size of a small city lay in the mountainside, like a star had fallen from the sky and crashed there. Trees lay toppled in a tangled mess all around the slopes down to the completely clear circular shape at the center, like some great force had pushed any debris away from it. No, not a circle, an oval… about the size of a human body.

He did not like those implications…

Several trees around the rim of the crater had also fallen (outward, away from it, what had happened?!), but he could see nothing moving or crawling away. Even in the winter, shouldn't there have been animals or…

Or was the threat still there?

Giyuu scanned the crater, eyes narrowed as he searched with every sense he could for something – anything that would—

He cut off as his senses honed in on a presence. He blinked. How… how had he missed that before? The aura the presence gave off… he'd never felt anything like it. Nothing that… heavy – that powerful.

Muzan. It had to be the Demon King.

Giyuu swallowed. Why did the worst and weakest hashira have to be the one to cross him? And he knew his Kasugai Crow likely hadn't been able to keep up. Normally, he'd wait for Kanzaburo at the nearest village when he ran ahead like this, and the messenger bird would catch up within a couple of hours. He was just so old…

And that had really come back to bite him this time.

He had to do something, though. He had to let them know.

Quickly, he took out his paper and his ink-stone. It took far too long and he had no idea how legible his characters were (it didn't help that he was trying to write in the dark, freezing weather and had to keep melting the ink), but it was better than nothing. Hoping his crow would see it if the worst came to be, he cleared off a decently sheltered rock and anchored the note with another stone. That would have to be good enough because he couldn't just let Muzan go.

Before he went into what he figured would be the hardest battle of his life, he closed his eyes.

Sabito, Makomo, Nee-san… please guide my blade.

And… he really couldn't put it off any longer, no matter how much he wanted to.

Racing around the edge of the crater, he steeled himself, hand on the hilt of his katana as he closed in on the presence.

Said presence sat in a leafless tree just outside the crater, one of the few that hadn't been knocked down, resting on a branch with his back against the trunk. Fortuitously, the figure wasn't looking at him, and that could give him the edge he needed. Giyuu knew he had one shot at this…

Taking one final breath, he decided to use his fastest form. Seventh Form: Piercing Raindrop, he thought as he drew his sword, aiming directly for the figure…

In an instant, something shot out of the figure's back and wrapped around Giyuu like a whip before he could change his sword's trajectory. Before he knew it, he'd been pulled off course. He grit his teeth. So, the demon had sensed him. He'd expected as much, actually.

So he went to swing down to cut the limb off, but another fleshy arm he hadn't seen came from behind and grabbed his sword. Out of his hand. He was a Hashira! That shouldn't be possible! (It wouldn't be possible for a stronger Hashira!)

No! He thought and reached for the sword clasped in the second limb, but to no avail. It withdrew and they hung there in the air, the night once again falling into silence, except for Giyuu's harsh constant concentration breathing.

"I won't hurt you, Giyuu-san," a soft voice said.

The Hashira's blood froze. The demon knew him. The demon knew him. Kibutsuji Muzan knew him.

How?!

Then the figure turned to look at him, red eyes glowing in the dark. Giyuu's breath caught because the kanji written in the boy's eyes (it had to be a boy, he looked so young) said Waxing Zero.

The Pillar swore he felt his heart stop. If… if this was what a Waxing Moon felt like…

"You're… not Muzan," Giyuu blurted out.

The boy's eyes narrowed dangerously. "No."

The Water Hashira decided it would be best to stay quiet. He wanted to ask about the 'Waxing Zero' distinction. They'd never heard of such a station before. Or what had happened with the crater. Was that a blood art? Just how powerful was this boy?

"He won't be a problem anymore," the boy whispered and turned away from Giyuu, an unreadable expression falling over his face.

The demon slayer blinked, brow furrowing in confusion.

"Who won't be?" he asked slowly, carefully.

"Muzan."

He… said the demon progenitor's name. Without any respect. Giyuu's eyes widened a little.

"How…?" he started but didn't quite know how to finish. How had the boy said that and not died? How had this happened? What was going on?

The boy must have thought he was asking how he knew Muzan wouldn't be a problem, as he answered softly. "Because. I just ate him."

If Giyuu had been shocked before, he went positively numb at that.

Because…

WHAT?!

After several seconds of stunned silence, the boy slumped down even farther. He looked… exhausted. If Giyuu had been in a better state of mind, he may have tried to break free and go for his katana, but something stopped him. He wasn't sure what. The lack of killing intent? The utter despair this being radiated? The lack of any actual aggression? The demon slayer's shocked state? All of that and more?

"As for how I got here," the boy said. "I'm not sure I can explain the long version right now. For the short version, you need to know a couple of things.

"One, my name is Kamado Tanjiro. Nice to meet you." He sounded too tired to actually mean that, but most demons didn't even go that far, so Giyuu could appreciate it… a little. "Second, the first time I lived my life, I became a demon slayer but eventually got turned into a demon," the Hashira winced. Every demon slayer feared that possibility. The boy didn't seem to notice and continued, "I managed to activate the final form of my blood art and woke up about three years in the past, completely human again. Since then, whenever I die, I wake up on that day—the day Muzan initially attacked and killed my entire family.

Giyuu could only blink.

"After several 'resets', as I've taken to calling each lifetime, I discovered that if I sent my family away and distracted Muzan well enough, he would turn me into a demon but everyone would live." He ran a hand through his hair, fingers lingering on the back of his head and scratching absently. "There's more to it, but over the course of nearly one hundred resets, I was able to build my strength and regain my mental faculties faster each time. My goal was to destroy Muzan's threat once and for all.

"It all accumulated yesterday, before I died the most recent time."

He suddenly looked lost in a memory, even though he continued to speak.

"We'd caught up with him, destroyed his Kizuki and most of his other demons. Morning was coming and we had him on the run." He shook his head. "But then I made the stupidest, most selfish decision… and it cost us everything."

xXx

The Previous Day

Something inside Tanjiro had snapped when he'd seen his brother as a demon. His family was supposed to be safe and yet... he'd failed them. Again. And for the first time ever, he'd chosen to just let go. He'd released the iron grip he had on his self control, unleashing everything he'd been unable to address: fury born of literal lifetimes of frustration and exhaustion, disgust, and utter loathing. It had flown out of the corner of his mind he'd shoved it into like a tsunami. He'd attacked Kibutsuji Muzan with all his might, fueled by his hatred, pouring all of his demonic strength into tearing the other being apart. It had been (and still was) so satisfying to turn the tables and let the supposed 'Demon King' know that he was the weaker being – that he'd been outmatched. Unfortunately, the other being had gotten wiser over the course of the battle, using harder surfaces to coat his attacks, making them more difficult to absorb as he struck at Tanjiro. No matter, though. It was only a matter of time, and they both knew it.

Tanjiro knew something was wrong with him, had known since the beginning of the fight, even beyond the whole 'becoming a demon progenitor' thing. He knew he wasn't acting normally… but Muzan was right there. The man – no, the monster who had tortured him and his family again and again and again. The being who had driven Tanjiro to the brink of sanity more times than he could count and pushed him off, laughing the whole time.

The younger being had pitied the older once. Still did, in some ways, but… he also hated him. His very existence disgusted Tanjiro on a level he wasn't sure he could address – wasn't sure he wanted to. He hated how much he hated… no, he hated how much he wanted to hate this being in front of him. How much he longed to make the other live in agony.

In response mainly to that, and mostly out of habit by this point, Tanjiro had planned on just absorbing the other progenitor completely, finally filling that void in his stomach entirely and being done with it… but only after he thoroughly terrified Muzan. It couldn't be a fast and easy death, after all. That would be an insult to everyone's suffering.

You could do more… a voice whispered in his mind as he clashed with the 'Demon King again. It sounded… actually, a lot like Muzan, but while that made Tanjiro sick, what the voice said also intrigued him – appealed to him in a way he couldn't describe. You could make him pay for longer – show him, unequivocally, how outclassed he really is. Make him feel what he's been inflicting on others for the last thousand years… You could make him one of yours. He would hate that.

In another universe, another time, Tanjiro would ignore that thought and cling onto the last vestiges of his humanity. He would not even entertain such a thought. In this universe, though, he realized the voice was right. He… he could do that, he'd had that ability for a while. Since he'd become a demon in that time-loop, he'd somehow mutated his demonic cells so they ate Muzan's, hence why he could absorb the other progenitor.

But, no. He had to end it. He'd already decided.

He won't let you end it. Not if you give him the slightest chance to escape. The voice said again as Tanjiro met the other demon in mid air, power clashing around them and shooting away at incredible speeds. He didn't care. He hadn't cared when they'd been in the infinity mansion, and couldn't bring himself to even as they continued to exchange blows that could level city blocks, hovering over a forest. He may have been concerned had they been in a city, but part of him just felt so numb, he wasn't sure he could care at this point… and he'd hated that too.

(How he could hate something and feel numb at the same time, he didn't know, but he also didn't exactly have the time or will to figure it out at the moment.)

You're avoiding acknowledging the truth, the voice continued to hiss at the back of his mind. Tanjiro didn't wince, he was in the middle of a battle after all. Instead he'd willed his arm to grow large, both around and long, pushing aside Muzan's own similar attack. Where their appendages met, he pulled and holes appeared in the other. Muzan shrieked in pain, fury, and fear. Music to Tanjiro's ears on top of satiating the demonic hunger.

(It shouldn't be satisfying.)

(It never had been before.)

(This was wrong.)

He always has a card up his sleeve, the voice went on. He did when he encountered Yoriichi, the only other time he's ever been truly threatened. He'll have something to do here. But you can stop that.

Just as the voice finished speaking, Tanjiro saw the opening. Muzan was lunging at him, maybe hoping to get past him as he had before (hence why they were up here fighting instead of down below), but the same thing wouldn't work twice. He caused an arm to grow out of his side (he would have to thank Akatsugi for his tutelage on demon flesh manipulation later) and ducked under the supposed attack. Then he made his arms grow again, then go boneless, going to wrap around the other. Muzan ran into his outstretched third arm, and it too wrapped around him. Tanjiro's other limbs joined them, encircling the figure from the other side and instead of him shooting past Tanjiro, the younger held the older completely immobile. They landed on the remnants of the infinity mansion below, now a mound of rock, wood and broken tatami mats.

Tanjiro grinned in triumph because he'd won! From the look of horror and fear on Muzan's face, he'd realized it too. Tanjiro brought him closer, opening his mouth to ask if he had any last words but…

No. The voice was right. He needed to nip this in the bud.

"I was going to ask if you had any last words before I eat you," he finally said. Muzan opened his mouth to respond, but before he could, Tanjiro jammed one of his fingers into the other Progenitor, injecting his blood. Muzan froze in disbelief, and then pain as Tanjiro went on. "But I think I like you better alive so you can pay for what you've done. So you can begin to understand the pain you've put everyone else through."

It felt good to see Muzan's eyes roll into his head, mouth open in a silent shriek of agony. How many times had Tanjiro seen people turning into demons look like that? How often had he seen his family looking like that?

He grinned wider as he felt the connection between them begin to form – the connection that cemented Muzan as inferior.

Of course, that's when everything went wrong.

Because Muzan may be the weaker demon progenitor, but he was still a progenitor. A thousand-year-old demon progenitor. No matter one's power, that should not be taken lightly.

Muzan began to writhe, his limbs expanding grotesquely in random places. Tanjiro frowned. That last one had almost broken through his—

A shudder rushed through the older progenitor, and as his limbs expanded, he also thrust his hands out and up, breaking through Tanjiro's restraints. He winced in pain as his arms were torn apart, and drew back, watching the other demon with a frown. Was this supposed to happen? Tanjiro's arms and body reformed into their original shape. Muzan's didn't.

He let out an unholy shriek and grew larger. Yeah, that was not supposed to happen, Tanjiro decided. Fortunately, he wasn't the only one.

"Fourth Form: Rising Dust Storm," Sanemi shrieked, his sword cutting through Muzan in several places. From what Tanjiro could see, those all coincided with one of the many hearts and brains Muzan held within his body. At least, from what Tanjiro remembered. He wasn't calm enough to reach the Transparent World at the moment.

Perhaps he should fix that.

Especially as Muzan didn't seem to recognize – or even acknowledge – Sanemi's cuts.

"Demon Blood Art: Compass Death Needle," Akatsugi yelled, then came barreling in with his own nichirin daggers. "Fifth Form: Hailstorm Bullets!" the former Kizuki launched into the air and began to punch and kick even as Sanemi finished his own strikes, just barely avoiding the rain of energy shots. Then Akatsugi burst forward and upwards, reaching the pinnacle of his arc before using his power to shoot down, hands at the ready. "Sixth Form: Crashing Glacier!"

Tanjiro felt his eyes widen at the sheer force of Akatsugi's attack. Even he found himself stumbling back from the pure pressure of the air rushing outwards before the entire hill began to collapse in where Akatsugi had punched Muzan.

For several seconds, all anyone could pay attention to was the collapsing hill and shifting rubble, but then it fell into quiet. Tanjiro could sense Muzan, though. He wasn't dead. Before he could do anything more than grit his teeth in frustration and anger, the Demon King burst from the ground, shooting into the air while laughing. He'd become… something else. Even the disturbing, giant baby from Tanjiro's last life didn't compare to this.

His head barely resembled a human's. His teeth had grown out long, still sharp, but moving and clicking around like mandibles. Several glowing, plumb-red eyes had sprouted all over his head, even under the scraggly hair that flew around in the clumps of the pressure he exuded. One of his arms looked permanently bulky while the other had grown long, as had the claws on the fingertips. That hand folded back in on that arm like a praying mantis'. Several tentacle-like appendages grew from his back and legs, which also mismatched. One looked to be from a kangaroo or rabbit, while the other looked thick and trunk-like, covered in scales and ending in claws again. Honestly, they were kind of lucky he hadn't lost all of his clothing, even though it hung in tatters from his body.

"Ha, ha, ha! I can feel it! The power to walk under the sun! It's finally within my grasp!"

Oh. Tanjiro gulped and looked down at his hand, just realizing he may have made a huge mistake.

"I told you! You are centuries too early to think you can defeat me!"

For a moment, Tanjiro wondered how the other being could talk with his teeth like that, but then he pushed the thought aside and took a deep breath. He needed to focus. He reached out to the older demon and tried to shove his will onto him. He never thought he'd willingly try to do so to any other being, but… he had to stop this. If Muzan was able to gain sun immunity…

Muzan winced and grabbed his head. "You… cannot… control… me!" he grit out, grating voice loud enough to easily be heard.

"Yes… I… can!" Tanjiro replied, teeth gritted so hard he felt them begin to crack.

"Nii-san!" he heard two voices yell and glanced over to see Nezuko and Takeo – still a demon, that wrenched at his heart – picking their way hurriedly over the rubble of the hill that used to be the infinity mansion. He lost his concentration on Muzan, who used that chance to shoot a multitude of arms and appendages towards Tanjiro.

"Demon Blood Art: Typhoon Beam!" Sanemi screamed and the appendages severed in half as he spit a column of compressed. The bottom half of the limbs fell to the ground. Muzan shrieked in anger and pain, withdrawing for just a second, which was when the Wind Pillar rounded on Tanjiro.

"What have you done?" he shrieked, gesturing to Muzan, who still hovered in the air. Below them, in the center of the crater, Akatsugi just stared up at the monstrosity above him in horror.

"Dance of the Dragonfly: Compound Eye Hexagon," Shinobu, also a demon (Tanjiro had to think back to when that had happened and began to realize just how far he'd lost himself) rushed forward and up, great bat-like wings colored like a butterfly's flapping powerfully to get her into the sky. She stabbed Muzan several times before thrusting her hand forward and into his chest, somehow taking it off the sword while still finishing her form. "Demon Blood Art: Poison Injection."

Muzan screamed in pain, then turned and batted Shinobu down.

"NO!" several people yelled at once as she shot towards the hill below and crashed hard. Tanjiro sensed immense pain from her, but thankfully, her life-force didn't waver. For once, he was thankful someone had become a demon.

"NII-SAN!"

The world around Tanjiro slowed down as he saw his siblings get closer. The first sunbeam shot past the horizon, landing on Muzan, who screamed louder, but it wouldn't be enough. He had Tanjiro's blood in him now. He'd adjust to the sunlight.

Genya – now looking like a werewolf if one of his parents had also been a giant bat – had taken out his gun and was shooting his own blood art at the demon above them. Tanjiro saw Rengoku and Himejima rush forward and…

He could see it suddenly and clearly. The humans would die. The demons wouldn't, but they would be beaten down again and again if this continued on. They… were on the verge of losing. They'd been about to win but now they couldn't.

And it was all his fault.

He didn't know how Nezuko was there, but as far as he knew, she was still mortal, and Takeo was a demon now. They would not be spared from Muzan's wrath, of course. Could the Demon King force a mutation to a point where his cells would become stronger than Tanjiro's again? Where he would start to eat Tanjiro and his demons?

Was this where Tanjiro's thirst for vengeance and hatred had led him? With his family and friends in an untold amount of danger?

Guilt and regret overwhelmed him, but while Tanjiro was only just realizing the depths of the mistake he'd just made, he was not one to run away. No one could ever claim him a coward. And he would take responsibility for his decisions.

He had seconds to act; had to do so before his siblings got to him – because they would try to stop him and may get hurt (or killed) in the process. He had to save everyone there.

Taking a deep breath, he reached for the power Akatsugi had given him, and pushed off with a burst of his own power, plus the extra invisible force from his subordinate. He left behind only tears and one last, sad smile to his siblings before he became a streak of color, aimed right at Muzan. Before the other could react, they collided, momentum taking them higher into the rays of the sun.

"Demon Blood Art: Palm Fire," Tanjiro said, then lit himself and Muzan both on fire as his arms stabbed through the other being. Pain overtook his entire body (so it looked like he could burn himself after all, he just needed enough will to do so), and judging by Muzan's writhing and increased shrieking, he felt it too. Tanjiro made extra arms grow from his back to counter anything his opponent could send at him. He just needed a couple of seconds.

Then he opened his mouth, concentrating all of his anger and hate and power to the front of it. 'Demon Blood Art: Demon Fire Explosion,' he thought, still gathering the power. A bright red ball of light and energy formed there. He gathered more and more energy. Muzan's several mismatched eyes went wide and he struggled more, but he couldn't get away from Tanjiro. Not fast enough.

'Goodbye,' he thought to everyone below. Live.

And then he let the technique go.

xXx

Below, Takeo and Nezuko screamed as they watched the enormous explosion in the air above them; as they watched their brother sacrifice himself to take out Muzan.

And… he had. Nothing but dust and smoke remained in the air where they'd been, all drifting away on the wind.

Everyone else stared in shock as a barely visible Nezuko fell to her knees, still staring at where Tanjiro had just been. Next to her, Takeo dropped the sword he'd been carrying and also fell down, landing on all fours as he stared in horror at the sword and rock below him as if he couldn't see them.

Then he screamed.

"NIIIIII-SAAAAAN!"

xXx

Kamado Tanjiro had taken the demon king with him. His sacrifice was honored in a ceremony attended by more people than he likely thought would have ever cared. He was given the highest accommodation by the demon slayer head, a carved, metal disk Ubuyashiki-sama had made to be shown off in the family home or on his grave. It was given to the silent Kamados at the ceremony.

All demons, it seemed, had been weakened when their progenitor died, but many of Muzan's demons still existed and so the Slayer Corps was not disbanded. Nezuko, Inosuke, Zenitsu, and Kanao all continued to train, each wanting to help to support the corps in the upcoming days as they tried to permanently eradicate demons.

Genya and Sanemi actually sat down and talked about what to do in their future, but mostly decided they wanted to wait until Shinobu had a cure before they went anywhere, but they would be waiting together. Most of Kamado's other demons did the same.

Shinobu did her best with what she had, but it still took her over a year to make a cure as she no longer had an unlimited source of progenitor blood to work with, so she was more cautious than she otherwise would have been in her experiments. But with that, every one of Kamado's demons – and a fair number of Muzan's – were turned back into humans.

Unfortunately, due to the shock of them having been a demon to begin with, many of the latter did not take this well and had to be restrained for their own good. The road to recovery would be long and hard for them, if they could recover at all.

No one knew where Yushiro went, but Shinobu had a sinking suspicion that he'd walked into the sun one morning with his cat, wanting to be with his beloved Tamayo-sama again.

Everyone else picked up the pieces of their lives and tried to return to normal.

All in all, life went on without Kamado Tanjiro, but everyone agreed that the world was poorer for it. However his sacrifice allowed them to be there at all, and so, while it hurt, they lived on in his name, praying that his next life would be at least a little easier.

xXx

In another dimension – another all-too-familiar time – Kamado Tanjiro woke up.

xXx

AN: So yes, here is the alternate ending in place of chapter 85. :) Thanks to Found and Quathis for their help beta reading! Also, if this seems a little repetitive, it's because it was posted as its own story on AO3. I edited it so it should be easier to just read as an Alternate Ending here, but I may have missed some things. Apologies.

Discord: discord. gg/xDDz3gqWfy (no spaces)