Alright, so I've been thinking about this story for a long time, and with the recent releases of S3 for both fandoms (That statement alone should tell you when I first started this chapter. XD), I've finally gotten around to writing this. Fair warning, I thought of the premise of this well before reading through to the end of the manga for both series, and originally came up with it with only knowledge from the first two seasons of both shows. Having now read through to the end of both manga at least a year ago, I now have a better grasp on how this story will go.
SPOILERS will be present for Demon Slayer, (along with a single minor, unimportant [for now] piece of info that's revealed later in Dr. Stone that will apply to the OC's thoughts early in the chapter for a line or two) due to the nature of how this first chapter will end up going, and as a result the thoughts the OC will have through pretty much the whole story. So, though I find it unfortunate to say this, if you're Anime-Only and don't want future seasons of Demon Slayer to be spoiled for you, don't read this until… Probably a few years from now, when the anime finishes…
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For everyone that's stuck around despite the spoiler warnings, or have read through Demon Slayer and already know of all the plot, I have one last piece of info, in regards to the "final chapter".
…I'm basically "disregarding" the Canonical "epilogue" for Demon Slayer, due to having come up with this idea, and made a number of notes before I reached the end. As a result, the canonical descendants of Tanjiro and the others are nigh-non-existent in this version of the universe. I hope that doesn't turn away too many of you, but for those of you that still stick around despite this information, I hope you enjoy Kosuke Kamado's journey through the Stone World as a part of the Kingdom of Science.
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"Nezuko would never eat a human!"
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Total Concentration, Water Breathing: Water Surface Slash!
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"Muzan Kibutsuji! No matter where you go! I promise you won't escape me!"
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Hinokami Kagura: Dance!
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"The bond between Nezuko and I cannot be severed! Not by anyone!"
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"We're in danger! You've gotta wake up! All of this… It's all a dream! Open your eyes!"
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"Hinokami Kagura: Clear Blue Sky!"
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"If you are feeling disheartened. That you are somehow not enough. Set your heart ablaze."
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"The Flashiest place in Japan that's teeming with lust and desire. A hotbed for Demons. The entertainment district."
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Hinokami Kagura: Raging Sun!
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Flame Dance!
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Hinokami Kagura: Fake Rainbow.
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"Hinokami Kagura: Fire Wheel!"
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Recovery Breathing!
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Hinokami Kagura: Burning Bones Summer Sun.
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Striking with all my might won't be enough! I need 100 times the force! Summon every ounce of strength left!
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"Thank you very much!" ~Thank you very much!~ ~Thank you very much!~
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Hinokami Kagura: Sunflower Thrust!
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"Hinokami Kagura: Sun Halo Dragon Head Dance!"
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"Humans don't need a reason to help out one another! And if you can't wrap your head around something like that, you're the fiend!"
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"Hinokami Kagura: Flame Dance!"
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Total Concentration: Dancing Flash!
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Right! Clearer… Give me a clearer view! Clearer! …Found it! Inside it's heart!
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"Morning!"
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"Thank Goodness!"
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"Giyuu-San… Isn't whatever Sabito entrusted to you keeping you two together?"
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Remembering the faces of my loved ones… "Set your heart ablaze."
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"MUZAN!"
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"Kaaaw! Deceased! Shinobu Kocho is deceased! She fought with an Upper Rank Kizuki and died!"
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"AKAZAAAAA!"
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Hinokami Kagura: Fire Chariot!
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Hinokami Kagura: Solar Heat Haze!
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Hinokami Kagura: Setting Sun Transformation.
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Why did he attack himself? Why…? For a moment, I smelled gratitude from Akaza. Why did he smile?
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"Kaw! Shinobu! Kanao! Inosuke! These three! Defeated Upper Rank 2! Defeated!"
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"Muzan, you are a being that should not be allowed to exist."
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"From here on, I will drive you above the ground!"
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"There's still one hour and a half left! One hour and a half until sunrise!"
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"Kya! Ha! Ha!"
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"Hinkoami Kagura: Beneficent Radiance!"
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They… Connected! All twelve! I'll repeat it, this cycle of twelve! Until the sun rises!
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"The hands, the feet. Give back all of those lives. If that isn't possible… Then die a million times as an apology!"
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"Tanjiro! Tanjiro, don't go! Don't leave me here!"
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"Old man Saburo!"
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Crk
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Crrrk
Crk-crk-crk!
CRKCRKCRK!
CRACKLE!
Stone cracked all around a statue, before moments later, the stone shattered apart as it was revealed that it was actually a person who had been encased in stone. Kosuke Kamado gave a gasp as he was suddenly subjected to the bright light of the sun, blinking in an attempt to get used to it. After a few moments, he managed to sit up, only to immediately flinch as the movement broke more of the stone around his body, and everything below his shoulders was immediately surrounded by cool water.
Shivering, the teen attempted to move, only to nearly fall forwards into the water, barely managing to steady himself, and looked down to find that the lower half of his legs were stuck in mud. Blinking, he raised his head and finally took in the area around him for the first time.
The first thing that Kosuke realized was that his hands were holding something under the water, and looking down as he lifted them slightly, his eyes widened at the sight. "Yoriichi's katana…" He muttered, looking down at the sheathed katana in his grasp. It was one that had been passed down in his family over the past few generations since his great-great-grandfather had used it. Although, now he was even more familiar with it, after…
The teen shook his head, looking around as he dragged his focus away from the sword that felt right in his hands, in order to take in the immediate area. As a result, he found that he was standing at what he assumed to be the edge of a lake, with his feet and shins sunk into the mud at the bottom. He could also see that all around him, nature was flourishing. And then, his eyes widened as a new sight greeted him when he turned to his left.
Lying half-buried in the ground, was a stone statue of a human, hands reached up as if to shield it's face from something. And there were a few others that he could see, all with their faces crafted in various states of shock, horror, or confusion. However, the teen knew that these weren't just statues. After all, he'd been just like them only a minute ago. Every statue that he could see, was a person, who was stuck in a stoney prison.
Shaking his head, Kosuke gazed at them sadly. "I see, so it happened to everyone else, as well…" He muttered quietly, his grip tightening on his sword for a few moments at the thought of everyone being stuck as statues. However, he couldn't do anything for them at the moment, and forced his grip to relax as he breathed out a reluctant sigh.
After a few seconds, he reached to his right, placing his sheathed sword on the bank of the lake, flinching at just how worn down he could see the handle and sheath were looking and worrying about how the blade inside might look, before putting that thought to the side for now, and grabbing onto the vines that were growing there. He pulled on them for a few seconds, until the slack was resting in the water, and they were taught against the roots they were growing around. With that done, the teen started shifting his legs, while at the same time pulling on the vines in an attempt to get free.
It took around ten minutes, and a few snapped vines, before he eventually managed to free his right leg. With that done, he was able to use it for more force inside the water, and the second leg came free a couple minutes later. Climbing up onto the bank, Kosuke picked up his sword, before standing up on his feet. However, he winced as he realized how caked in mud they were, and took the next few minutes to clean them off in the lake, before standing up and turning to face the nearest statue only a few feet away from him.
He put his hands together, and bowed his head to them. "I'm sorry. I wish I could do something, but even I don't know how I broke out of the stone." He told them, even though he already knew that the person he was talking to couldn't hear him. "However. If I do find out how, and there is a way to replicate it, then I promise!" He exclaimed, lifting his head to stare at the statue of the man with a look of determination. "I will come back, and I will make sure to break you and everyone else out of that stone!" Kosuke declared, staring into the statue's eyes to convey his feelings… And then lowered his head and sighed.
After a few moments, he raised his head and looked up through the trees, noticing the sun was around a quarter of the way up… Or maybe it only had a quarter more to go before night fell. Kosuke couldn't be sure when he'd woken up, or where. And he definitely couldn't remember which way he was facing… Not that it would've mattered, since his statue could've been moved any distance by water, or the earth, or anything else in the time he'd been… Petrified.
Actually, how long has it been…? The teen wondered to himself, looking around once again and really taking in his surroundings. When that bright green light had moved across the horizon and bathed him in it's light, he'd been standing in the field outside the school… It had been just past noon, and he'd brought in his great-great-grandfather's sword that day for a project and was carrying it around with him… And then he'd been stuck in that inky blackness, unable to do anything aside from think to himself… Or rather, that's all he'd been able to do until the Visions started…
Kosuke shook his head, gripping his family katana tighter as he looked around. "Whether it's early in the morning, or late in the afternoon doesn't matter right now. There's one thing I have to do before anything else." He said, giving a serious nod… Before shivering and slouching over slightly. "...Make myself some pants of some kind." He muttered quietly, moving over towards the trees to see if he could find any leaves or vines or anything else that he could use to cover the upper part of his lower body.
With no prior knowledge, it took Kosuke somewhere around an hour to make himself anything resembling "clothes" to cover himself with, and even that was a stretch. They made him feel he was "decent" though, so he was able to walk around the forest he'd found himself in without much issue. His katana was still held in his hand, since he had no idea how to fashion anything that might work to hold it to his "pants" while still keeping them up, and he honestly just wanted to get moving to explore the area, and see if maybe anyone else had broken out of the stone like he had somewhere around the area.
After all, there had to be some reason that he'd broken out. He couldn't have been the only one after however long it had been… Right?
Over the time it had taken him to make his "clothes", followed by picking a random direction to start walking due to no discernable landmarks, Kosuke was able to find out that it was definitely some time early in the morning, due to the fact that the sun had slowly risen in the sky.
Putting a hand above his eyes to shield them from the worst of the light, Kosuke squinted, and attempted to figure out the sun's position in the sky. "I'd say it's probably somewhere around… Nine in the morning." He guessed, before giving a light chuckle as he lowered his head and shook it. "And to think, I wouldn't have been able to do that before I got stuck in that recurring vision…" He muttered, before raising his head as he continued to walk forwards.
Every so often, he would take in a deep breath through his nose, glancing around himself as he did so. If there was one thing that anybody who knew the Kamado's could tell you was passed down through their family line, it would have to be their sense of smell. That had been a slight detriment to Kosuke back when he was constantly surrounded by cars letting off exhaust, and all the pollution making its way through the air.
But now, the smells that greeted his nose were fresh, clean, and he couldn't help but smile every time he took a deep breath. However, every time, he would frown a few moments later. Because as enjoyable as the refreshing smells were to his nose, the complete lack of any smells that could be attributed to humans always saddened him, as his hopes of there being anyone else outside of their stoney prison were chipped away with every breath in.
A few minutes later, as he pushed a branch out of his way and stepped over a few stones, he took another deep breath… And paused, freezing in place. He emptied his lungs, and then took another, deeper breath in through his nose. The second the smells in the area hit him, he immediately jumped off the rock, onto the forest floor, and took off in the direction of the new smells that were mixed in with the others that he'd been getting used to.
A few seconds later, he slid to a halt in a seemingly random area of the forest, staring through the trees. And yet, he had a wide smile on his face. "Other people." He muttered to himself through his grin, taking in another sniff, and finding the smell of four humans lingering in the air. However, the smile slid from his face as he focused on the smells more closely.
The first three scents are weaker… Male, male, female… All of them are somewhat nervous, but also determined… And, somewhat familiar. He thinks to himself with a small smile, before taking another sniff, and tensing. The fourth smell, it's stronger… Probably only a few hours old… Male, he's feeling determined… I don't recognize this one, but he's strong. Kosuke could feel sweat on the back of his neck as he focused more. And there's some bloodlust as well. He realized, gulping. However, he pushed his nervousness to the side, and narrowed his eyes. "Whoever he is, he's after the first three. They need help!" He exclaimed to himself, gripping his katana tightly, and taking off, following the scent trails through the forest.
However, he could tell even before he'd started running. He was weaker than the fourth person. And that translated to being slower than them if they were running, which it was likely that they were, if the spacing between footsteps in the dirt that he could sometimes barely make out were any indication. Kosuke grit his teeth, his grip on his katana becoming even tighter at the thought of being too slow, too weak to do anything to help the other three people who had woken up in this new world alongside him.
With lives on the line, and the thought of being unable to do anything echoing through his mind, Kosuke forced his body to skid to a stop, before calming his breathing, despite how much he wanted to continue rushing forwards. He breathed in, he breathed out.
He breathed in.
He breathed out.
He breathed in.
He emptied his lungs.
…And then, he breathed in. Deeply.
Clouds spread around in the sky, a small number of them changing from a dark gray to their normal fluffy white after the rest had already cleared away, the forest and the mountain it surrounded drenched from the rain that they had dropped. At the foot of that mountain stood Kosuke, down on the ground on all fours, his family katana on the ground beside him as he hacked and coughed his lungs out.
It had been close to nine hours, and this was the second time he'd been forced to pause in his rush to catch up to the other four people that were around in this… This Stone World that they'd woken up in. He may remember doing the actions he'd done to run here thousands upon thousands of times before, and he'd even done it himself a few times in the past for around 12 hours… But his own body couldn't handle it when it was combined with forcing himself to run, duck, weave and leap through the forest following the scent trails.
He forced himself to take a few deep inhales, steady out his breathing, and grab his katana as he forced himself to his feet, one hand resting on a tree beside him. The scent trails were practically gone thanks to the downpour, but he knew that the people were close. He'd heard what sounded like explosions come from this direction earlier, three going off in succession telling him they were likely man made.
Kosuke took in a deep breath through his nose, grimacing when all he could pick up was the smell of the storm and the rain, even if the storm had dissipated a short while ago. Focus. Find their scents. They could be in danger! He thought to himself, steadying his breathing and closing his eyes, before sniffing, and focusing on the various smells that he could detect.
Rain… Rain… Moss… Squirrel… Rain… There! He thought to himself, his eyes opening wide as he was able to pick out four of the familiar smells. Two of the first three are together, one of the guys and the girl… The other guy is separated from them… He takes another sniff, closing his eyes in concentration. The two that are together, I can only smell the forest, and some animals around them… Another sniff. The one that's separated from them… His eyes widened as he immediately started sprinting. The fourth person is in the same direction as them!
Kosuke grit his teeth, knowing that he was slow compared to the fourth person he could smell. But he couldn't risk doing his earlier actions now. He hadn't been thinking about his own body earlier, and how it couldn't handle the burden he placed it under for long periods of time. If he rushed to get there faster, it was likely he would just collapse as soon as he tried to face that person. And then he wouldn't be any help at all.
His eyes widened when he heard a quiet crash come from the direction he was heading, knowing that if it was quiet to him, he was still far away from wherever it originated and was no doubt much louder. He pushed himself as much as he could without placing his body under more stress. Please! Just be okay until I can get there! He thought to himself, praying that nothing bad would happen before he could get there.
He followed the direction the sound came from, and close to twenty minutes later, he could smell how much closer he was getting. However, while the scent of the person from the group of three was getting stronger, the smell of the fourth person had already been getting steadily weaker. And, there's a new scent! Kosuke thought to himself, wondering if the fourth person had known of a fifth, and left them there to do something with the first?
But, the fifth scent has some confusion, determination, and curiosity, while the first simply has determination and some excitement. Did the fifth person help the first? He wondered to himself as he continued to run forwards. Either way, I'm close! I'll figure out the situation when I get there!
Senku:
"I can't say that I can give one millimeter of support for what I just heard. We've just met, and you're already professing your love? Not how to handle an emergency." Senku said, unable to believe that he'd somehow managed to end up in one of those cliche situations where a girl fell for whichever random guy managed to save her from whatever unfortunate situation she'd found herself in. As a result of his words, the girl, Kohaku, she'd called herself, pointed at him immediately after she'd finished tying up her hair.
"I didn't say anything about falling in love!" She exclaimed, making him lean away from her. "I'm saying I like you as a person and I think the two of us can work together!" She yelled at him, making Senku blink as her words registered.
"Oh. Well, thanks. I appreciate that. 'Cause nothing's as illogical or prone to trouble as a romantic entanglement." He said while rolling his eyes. However, his gaze snapped to the side at the sound of rustling bushes, with Kohaku's attention immediately shooting in the same direction.
"Is the long haired man back?!" She wondered, her hands reaching behind her, only to grasp air, making her gasp as she turned, and saw her shield and knives still on the ground by the tree she'd been stuck under only a couple minutes ago. Senku gave a nervous chuckle as crouched slightly, scared at the thought of Tsukasa heading towards them for any reason.
I got lucky once… If it's him, then I'm 10 billion percent screwed. He thought to himself with a shaky grin. He'll probably fully cut off my head this time. He realized, his foot sliding back slightly as the bushes rustled even more, before a shape leapt out of them.
Senku and Kohaku watched as the shape slid to a stop in front of them, before all three people met each other's eyes. Senku's eyes widened in surprise, Kohaku's narrowed in caution, while the new arrival's eyes met Senku's, and widened as well. After a few seconds, Senku chuckled, before straightening up from the slightly slouched position he'd gotten into. "Yo… Kosuke." He greeted the new arrival, getting a light chuckle from the teen standing in front of him.
"Senku… Hey." The red haired and red eyed teen in front of him said as he stood up, one hand reaching up to rub the back of his head. "I wasn't expecting to see you… Your scent's changed a bit." He said, making Senku chuckle lightly, even as he filed that new piece of information away for later. At the same time, Kohaku relaxed her own posture slightly, but remained on guard.
"Well, as great as it is to see a new face, I've gotta ask… How'd you wake up?" He asked the teen, while in his mind, he thought over the situation. Tsukasa didn't know the Revival Fluid's recipe until he confronted me. Meaning he didn't wake up Kosuke… Is it possible that…? He thought to himself, right before the teen spoke up.
"Ah, I… Don't actually know?" The teen admitted, still rubbing the back of his head, before looking down at the family sword in his hand. Senku remembered that he'd brought that in for his class project the day they'd been petrified. But how in the world had the handle and sheath survived for over 3700 years? However, he's unable to voice this question as Kosuke continued. "It's just… One minute, I was… Dreaming, and then the next, I was opening my eyes and found myself submerged in a pond from the shoulders down." He admitted. And his words confirmed Senku's hypothesis as the white and green haired teen placed a hand on his chin.
The Nitric Acid. Wherever he was, it was close enough to the cave that he was exposed to it enough that he broke out of the stone naturally. Being submerged in a pond would also explain his sword. If it'd been above ground this whole time, there's no doubt there'd be nothing left of it. But if the whole thing has been submerged in water for even 36 hundred and 30 years, then it's not impossible that what we're able to see has survived this long, even if it's worn and the color's basically been completely washed away from everything but the pommel. That said, there's no telling how the blade itself is doing until it's taken out of the sheath. Although with how much rust is covering the hilt, I have a pretty good idea… The teen thought to himself, glancing at the rust-coated hilt in question. However, the attention of both "modern" teens was grabbed when Kohaku spoke up.
"Excuse me, but who are you?" The girl asked, making them both turn to look at her, and find that she was still slightly crouched, but was further away, her shield once more on her back, and both of her knives held loosely in her hands. Her grip tightened only slightly as she narrowed her eyes. "Are you with the long haired man?" She asked, her foot sliding forwards while she got into a crouched position as she asked.
In response to her question, Senku glanced at Kosuke. His earlier hypothesis made it unlikely, and from what he knew about the teen from their time in class together, it was nearly impossible that he'd side with Tsukasa's view of the new world they found themselves in. But, if he ran into Tsukasa on the way here, and he realized the kind of person Kosuke was and kept certain things quiet… He thought to himself, slightly nervous at the possibility.
Senku watched as Kosuke blinked at Kohaku's question, before turning to face him with a look of confusion. "Is she talking about the other scent that's here?" He asked, making Senku grin slightly. That response told him everything he needed to know as he chuckled, and relaxed completely.
"Yeah, c'mon, I'll tell you what you've missed." He said, digging a finger into his ear. "I've been awake for around a year. Taiju's been up with me for 6 months, while we woke up Yuzuriha a few days ago. The "long haired man" is called Tsukasa, who we woke up a couple days before her. Which, at the time, was our only option. But in the long run, it sure came back to bite us in the ass." He revealed with a chuckle, getting a hum of interest and slight worry from his former classmate.
Aaaand, Chapter One is done! Man, this was pretty fun! Mostly original scenes, focused on Kosuke Kamado waking up and exploring, before the Sense of Smell he inherited kicked in, and he immediately set out to follow his former classmates, even if he didn't recognize them at the time. There's a couple different reasons behind that, which will be explained later, but I feel like some of you may be able to figure out at least one of them from events early on in this chapter.
As for how he caught up to them so fast… Well, A: Obvious answer is obvious, even if the way I'm writing this doesn't have me admitting it outright in the narration. B: …Taiju talks about getting there "in 5 hours" when it takes the three of them a day and a half. So, apply Reason A to Taiju's words, and viola, it takes Kosuke 9 hours.
Now, probably the biggest part of this chapter that I feel like is going to need to be addressed, due to the nature of this show: The fact that Kosuke still has his Family's Katana, despite it being over 3700 years into the future. I will admit, that is something that I spent a good deal of time researching to see if it would even be possible to achieve… Which, the IRL answer? Still pretty up in the air.
But, this is anime, even if about 99% of the Science in this show is correct. As a result, when looking into things, I found out about the Cawood Sword, which was found in a River, and from what I understand was one of the most "well preserved swords" found, despite being there for somewhere around 700-800 Years. So, take that, apply a little anime SOD, alongside some attributes from the Demon Slayer franchise due to this being "Nichirin Steel" and not just "Regular Steel", and viola, Kosuke still has his Family's Nichirin Sword.
As for the state that the blade is in… Ehhhh… Well, those who've seen the third season might have a pretty good idea of what the Kingdom of Science will see when it gets unsheathed. Also, yes, I know, (More Manga Spoilers): In the Final Battle, we can see that the blade itself gets snapped while remaining stuck in Giant!Baby-Body!Muzan (Or whatever the fandom calls that form of his)… I'mma kind of hand-wave that, since it's not all that important, and it lets Kosuke have the sword.
Am I leaning a little far into the Anime/Manga-SOD and Demon Slayer Franchise Rules, alongside some Very-Minor!AU-Aspects in order to let Kosuke keep the sword? Yes, yes I am. I will fully admit that I'm probably stretching some boundaries with the explanations I've given and how believable they may be… But, it's the direction I've decided to go with this, and I'm happy with it.
Hell, if something like this is enough to likely upset some people, then it's likely those same people will really dislike something else I'll be using later… Here's a hint, for those interested, and may be turned away due to this information: …Author gave their "Word of God" for a certain part of the series that has constant arguments about it… I'll be following their words for the most part, but not entirely.
But, anyways, I've gone on for quite a while in this AN. So, for now, I'll leave it here. Just gotta finish off a few of the quotes during the final arcs at the top, re-read through this for spelling and grammar, and then this chapter's done… But, it's 2:20 at the moment, so I'll worry about all that tomorrow.
I hope everyone who's read to the end has enjoyed it, and I hope you will continue to enjoy the future chapters!