Here we go guys. This is the first time I've written Kimetsu stuff, so it might start off a bit wonky. You can expect at least one crossover pairing ( you can take a guess, it's kinda obvious ), so if that's not your thing I'm sorry. As with Sagittarius, while I recognize that Servants are arguably more powerful than Demons and Humans, I wanted to keep the balance in power— Musashi is ridiculously powerful, yes, but she's still human in this because I wanted that power balance. This is EoR Musashi, the one who is mostly human, but hasn't died yet and is on the cusp of being a servant. Obviously, because of that, she didn't die in Shimousa, instead was transported elsewhere (Musashi is an Isekai victim?) and since the focus is gonna be on Musashi, moments from Tanjirou's POV are going to be a bit rarer. Remember, Musashi is here to fuck shit up but in a good way, so obviously there's gonna be canon divergence, changes, and good god Shinjuro gets his shit together. Will there be deaths? Probably. But Musashi wants to save as many of her friends as she can. Also Butterfly effect and all that jazz.

Explanations aside, please enjoy this fanfiction to its fullest! This one will be slower in updates as Sagittarius, but as usual, talk to me! Reviews will be answered and talked about if there's confusion. Now, let's begin!

It had happened in the winter, Kyojuro Rengoku would later remember. He had been on his way back to his estate from a particularly grueling mission when his crow started talking up a storm.

A small mountain village nearby was getting overrun by Demons. Make haste, make haste!

So, despite his exhaustion, the Flame Pillar had taken off towards the east where the mountain village was. It hadn't taken him too long, he thought, but by the time he had gotten there, the village was silent.

The scent of blood strong in the air and his first instinct was to cover his nose, it was so heavy.

The village was very small— no more than seven or eight houses. Blood splattered the ground everywhere and his two-toned eyes gazed over the bodies and limbs strewn about.

Sadly, it was the fate of many smaller villages like such. Ones that the Demon Slayers couldn't get to in time. Kyojuro sighed, rubbing his shoulder as he walked through the village. Doors broken down and splattered with blood weren't unnatural but something caught his eye suddenly as he gazed at one of the walls of one of the houses.

Slash marks.

Made with a sword.

A clattering noise made him startle and his hand flew to the blade at his side. He slowly approached the house that the noise came from, stepping up the broken stairs and peering in. A figure's back was facing his. It looked like a woman from what he could tell, her hair a pale, almost white-tinted pink done up in a type of ponytail with a star-like ornament kept it in place. on her shoulders was a cloak of deep blue and a kasa was sitting next to her. She was sitting at a fire pit and she was moving— eating, maybe?

If she was the only one left, that must mean that she had to be the demon, then.

Kyojuro shifted, silently drawing his sword. First Style would be enough to finish her off if she was unawares. Easy. Then he could get to burying the bodies.

The woman shifted, the only warning he got before he had to bring his sword up to block a strike from her.

Red and gold eyes gazed into a single, blue eye with a magenta ring in the iris— the other eye covered by what appeared to be a kiku gata-shaped tsuba. The woman pressed against his blade before she broke away, sheathing hers without a word. She moved back to her previous spot, picking up a bowl of rice that had abandoned on the floor when she had moved.

"So you're not a demon, that's good," was all she said before she sat back down. "Wouldn't do me any good if another one showed up."

Bewilderment flooded his senses as he stared at the woman, who had started to eat again. He could tell from just one strike that she hadn't been using her full strength. And from that, he could easily tell that she wasn't just a woman who picked a sword up in order to defend herself. And considering how he glimpsed the hilts of four others under that cloak of hers, there was no way she was just an ordinary woman in the village.

She hadn't even been grieving for the people, just eating. He moved over to her slowly, blade still drawn as she continued to eat.

"Meaning you're not one either. Can I assume that the demons are—" Kyojuro found himself asking only to be cut off.

"Dead. They weren't much, I'll tell ya, ain't anything like the demons I know. Time must've really gotten to 'em," she said loftily and he raised a brow.

Time?

What was that supposed to mean? He frowned as he glanced around the room.

"If you want to know what happened to the villagers, most were eaten by the demons, the ones who weren't aren't in here," the woman continued, "Only a few bodies left though, I planned on burying them when I finished. Would've been a waste to leave the rice already made to the bugs."

She reached over, a second bowl suddenly in her hands and she held it out to him. He frowned, unsure at first, but he slowly took it from her. The two of them ate in silence before she set her bowl down, empty. He was only half done with his, but he stood when she did. The woman stretched her back out first, before she picked her kasa up, putting it on her head.

"Well, I guess I should start burying the bodies," she hummed before she turned. He scooped his blade up, following her as she stepped outside. She glanced over at him.

"If you're gonna follow me around, buddy, at least go find a shovel," she said before she walked down to the center of the village. Kyojuro's brows knitted together as he watched the woman. She hadn't recognized him, meaning she probably didn't know about Demon Slayers at all, or she just didn't care.

She had killed the demons all by her self, though considering how her reflexes were and the fact that she had five swords on her person, he shouldn't have been surprised. It was still dark, so he wondered how she had dealt with the demons in a manner that allowed her to casually take food from the deceased. He had gotten the message that the attack had been happening not very long before he arrived.

And he was sure he would have remembered hearing about someone who wielded five nichirin blades— or at least, he would have assumed so.

He ended up finding two shovels propped against the side of another house. He grabbed them both before walking over to where the woman was on the outskirts of the village. She had carried what remained of the bodies there, resting them each in a neat row under the pine trees.

No words were exchanged as he tossed her a shovel and she started to dig. he began after her, thinking as he worked.

Should he report her to Oyakata-sama?

She was a bit old to join the final selection, but if she had managed to kill… how many demons were there?

Kyojuro blinked before he glanced at the woman next to him.

"If you don't mind me asking," he started, looking back to the grave he was digging. "How many demons were there?"

She hummed a bit, climbing from the small grave she had dug and walked to the row of bodies before she answered.

"Four," she said, "Two who looked like full adults, one was a kid, and the other was an old man. The kid…" she frowned a bit. "No, never mind. She just dressed oddly. Not as modern for this time. Reminded me of my own. Learned real quick that my blind spot isn't really a blind spot the hard way."

She leaned down, picking up one of the bodies and moving it to the grave. Kyojuro blinked, his smile never wavering as he continued to dig. She didn't seem bothered by the bodies, he noticed, as if she was used to it already.

He wondered what kind of life she had led before. Certainly, it was one of being a warrior, if the five swords weren't a dead give away, the tsuba acting as an eyepatch certainly was.

But that wasn't what had caught his attention. The way she spoke was a bit odd. She mixed in a few older, more formalized words (he only knew them because his father would use them when he wasn't drunk or hungover) along with a few terms he hadn't heard before. Not to mention the constant usage of 'time' when she spoke.

She had said that 'time had gotten to' the demons and that the child demon she fought was dressed more from her own time.

And of course, the fact that she took down four demons so quickly and easily. As far as he knew, none of the blades she had were nichirin ones. It was rare for anyone in the Slayer Corps to use more than one— Uzui and Himejima were odd cases in that regard, especially Himejima and his ball and chain and ax combination.

Kyojuro blinked from his thoughts as the woman snorted suddenly. "Deep enough, for you?" she asked him and he glanced up. He had dug quite a bit deeper than he had planned to as he was lost in his thoughts.

He laughed a bit. "Ah, sorry!" he said, moving out of her way as she placed the body of a young man in it.

"Not a big deal," she said, standing up. He covered the body up before he started on the next one.

By the time the two of them finished, Kyojuro's fingers had started burning from the cold and light snow had started to fall. The woman didn't seem to be bothered, setting the shovels to the side against the closest house before coming back over to the graves. She sent them off with a prayer before she pulled her kasa back up over her head from where it had fallen while they dug.

Kyojuro hummed, looking up as his crow circled above. No missions had come in while they were digging, so either there was no demon activity nearby or Oyakata-sama already knew through that way he always did know.

"I've been meaning to ask," the woman said and he glanced over to her, head tilted as he smiled. "What's a fancy-lookin' guy like you doing all the way out in the middle of here?"

He blinked. "What do you mean?" he asked and she indicated to his sword.

"Last I checked, swords weren't cheap, and you don't strike me as one of those sword-smith types," she explained, "'sides, that Haori of yours looks awfully fancy too. You don't seem like the thief type, too obvious with that hair and your eyes, but hey. I'm not going to judge."

He snorted before he laughed a bit. "No, no you're right. I wouldn't say I'm 'fancy', but I'm not a run-of-the-mill kind of guy! Are you telling me you haven't heard of Demon Slayers even though you know about demons?" he asked gazing back at the woman as she picked at a dried bloodstain.

"Hm? Oh, no, I didn't know that we got a fancy title and all that," she said, "Ah, but different worlds, different rules. I hope I'm not breaking a law for taking out a couple of small fry demons. I mean, the kiddo was weird and had a number printed in its eye, but…" she shrugged and Kyojuro felt his movements freeze up.

A number printed in one of its eyes?

That would make it a Lower Moon Demon?

"You fought a Lower Moon alone?" he blurted, eyes wide as his smile finally fell away to a shocked gasp. The woman turned, brows furrowed as she tilted her head.

"I mean, yeah? I guess? I don't know what that is, but none of the Demons were all that hard to deal with," she said with a shrug before she pulled one of her blades out. "With the blade that Gramps gave me, and my eye, I can basically cut down anything supernatural. I mean, for the gods' sakes, the kid wasn't even half as strong as Hozoin!" she ranted but her words were lost on the Flame Pillars he bit his lip.

What a truly puzzling woman. One of her blades, she claimed, could cut through anything supernatural, but he was unsure if it was a nichirin blade. She mentioned that her sight had something to do with her fighting— which would make sense, but something told him that there was something more to it.

His lips twitched upwards in his signature smile as he shifted.

Once again, though, she had mentioned something (or rather, someone) that had to do with time.

It had been a long time since he had heard about him, but Hozoin could only mean one of five people. But it still didn't make sense— Hozoin In'ei died close to three hundred years ago.

He might not have been a Demon Slayer, but he had been somewhat famous for his spearmanship— enough that there were records of him in the Corps library praising him and the rest of his monks.

Something odd was certainly going on. This woman wouldn't have mentioned Hozoin as a comparison unless she had actually fought the man, right?

He glanced over to the woman, who was still talking about something.

"— I've reached Zero, but man, I'm still itching for a fight!" she huffed, arms crossed under her cloak and blade put away. "There's gotta be some strong guys around here, somewhere. I mean, maybe not as strong as old man Tajima, but still!"

He chuckled lowly. This woman was quite exuberant despite the formerly formal and cautious tone she had been using before.

"Oh sorry," he said as she glanced over, "I just thought it was interesting how you thought a Lower Moon was something easy to beat. A lot of Demon Slayers have fallen to them, I didn't think that a common woman would be able to beat one." He raised a brow as he continued, "Though you're no common woman, are you?'

She grinned a bit. "Nope. Shinmen Musashi-no-Kami Fujiwara no Harunobubu—!?" she stopped suddenly when she bit her tongue. Wincing, she laughed a bit, "Sorry, let's do that over! I'm Miyamoto, Musashi. The full name's a bit of a mouthful. Creator of Niten Ichi-Ryuu, and all that," she hummed and Kyojuro felt another bolt of shock go through him.

He knew the name Miyamoto Musashi. Just like anyone else who studied swordsmanship would.

"But you're a woman!" was the first thing he blurted, unable to keep the shock from his face this time. "And— Well, that was rude, but! Miyamoto Musashi—"

"Died ages ago, I know," she said with a hum. "But in a world filled with Demons, is it so unlikely that time travel can exist?" she asked him and he closed his mouth.

Time Travel?

He felt his lips twitch upwards again.

"Well, I guess I could," He admitted, "Demon Blood Arts are certainly diverse!"

Oyakata-sama would know what to do.

"What do you plan on doing now, Musashi?" he asked her and she hummed, adjusting her kasa.

"I'm not sure," she said, "Wander, I guess, try and find some strong guys to fight, get some food, and then continue on to wherever Kannon-sama guides me." she shrugged.

Food, was it? Or maybe he should target her wish to fight some strong opponents…

If she didn't know where she wanted to go and what to do next, then maybe…

"Well, if it's food you're after, I can't really offer much," he said, "I love eating tasty things, but I'm a menace in the kitchen! But I do know where there are some powerful guys about!"

She seemed to perk up a bit at that. "Oh?" she asked, blinking. He nodded.

"I told you, didn't I? I'm one of the top Demon Slayers in the Corps!" he barked with a laugh as he brushed snow from his haori. "You should join us! You'll get to fight all sorts of people!"

The woman— Musashi— seemed to consider it before she grinned, nodding.

"Well, when you put it like that, I guess I can't refuse!" she laughed and he grinned before he bowed a bit.

"Rengoku, Kyojuro! The Demon Slayer Corps' Flame Pillar!" He said.

"You can call me Musashi," she said, bowing in return. "My udon bowl record is 634."

"That's impressive!" he laughed as he began walking, Musashi following him. "I think you have Kanroji beat!"

She chuckled as they walked down the mountain, the two of them talking on the way.

The conversations were light and non-revealing about each other and their pasts. The only thing he learned about her was that she held Kannon in high regard and had been in what used to be the Shimousa province prior— he had told her that it was called Chiba now and she made a face, her hand reaching up and lightly ghosting over her eyepatch.

He wondered how much Time Travel messed with her knowledge of Japan.

He didn't reveal much about himself, despite his outwardly friendly nature he was still cautious. He did tell her that his favorite food was sweet potatoes, which she responded that she was always glad to get free food, but udon was a top spot for her.

He only laughed, telling her that he wouldn't have guessed.

He hoped he was making the right choice to take Musashi to Oyakata-sama.

His instincts told her that she was a good person, and she would be a powerful ally if she joined the Demon Slayers.

Could she even become a Demon Slayer?

She was a bit old to take the Final Selection, wasn't she?

Kyojuro felt that if this woman was with them, the task of wiping demons from the earth just got a bit more believable.

There was just something about the way she carried herself.

He hoped that he made the right choice.

Translation notes:

kasa: straw hats that are seen often on travelers. Lostbelt Musashi wears one and in the special promo video, she's also wearing one. I'm not sure if Izou's in his second ascension counts as a kasa but it might.

kiku gata: The floweresque shape seen on katana guards. It was the closest I could get to the design.

tsuba: The sword guard! Musashi's eye is still damaged, but because uh reasons, Musashi's damaged eye can now only see karma, curses, and the whole Heavenly Eyething.