"UMAI! UMAI! UMAI! UMAI!"

"Wha-"

"That's the flame hashira? Are you sure that it is not just a random glutton?"

"Who cares, let's talk to him!" Y/N says, excitedly running over to him.

"W-wait! Y/N! He might be a strange person-"

… Your smell…why are you so excited to talk to him? Is he that incredible? No…rather, your smell, you like him?! But you guys never even talked properly before!

"Rengoku!" Y/N approaches him from behind and exclaims, he chokes on his food and started to cough violently in response.

What's with this amused look she has?! She scared him purposefully?!

After he finally recuperated from almost dying by suffocation, Rengoku turns to see the girl.

"You're the flame hashira right?! I admire you a lot, please marry me!"

"…. Oh! You are the mochi girl, right?!"

That's what he's worried about? Did he just ignore the fact that she asked his hand in marriage?!

"Yeah! Though it's a bit embarrassing to be recognized as the mochi girl ahaha-" Y/N says with her hand behind her head as she laughed awkwardly.

"No need to feel shy! Not many people would have the courage to stand up to a hashira like that, I admire your guts!"

If Y/N was a dog, her tail would be violently wagging right now.

"Also, I heard a lot about you from Sanemi!"

"I bet he said that I have mental problems or something."

"Exactly!"

"Eh?!"

"However, I know Sanemi enough to see when he likes someone! He's a hard person to crack, so the fact that you actually managed to befriend him is a sign of how much of an admirable person you are!"

"Me and Sanemi? Friends? Pfft!"

"There! Have one!" Rengoku says, pushing one of the bento boxes to the girl and patting the place at his side for her to sit.

"Thank you!"

I will keep the box and make it into a family heirloom!

Tanjiro, tired of being the third wheel, then speaks. "Uhh… Excuse me-"

"Oh, xhis ix goodx!" Y/N says with her mouth full of food.

"UMAI!"

"Uh, yes… I totally get that."

♡

After sitting in the place across the table, Tanjiro then explains about what happened in the Natagumo mountain.

"Oh! So, that's it, huh! Well, I dunno!"

Y/N was still eating bentos, since the train will be destroyed at the end anyway and all the food in it will be wasted, she might as well eat as much as she can!

"And this is the first time that I have heard of the Hinokami Kagura, but it's great that your father was able to apply kagura to fighting! And that's enough of that topic!"

"Huh? Can't you help a little more?!"

"You both should be my tsuguko! My disciples, I'll look after you guys!" Rengoku says, resting his hand on top of Y/N head, who was still sitting by his side while eating.

"Not so fast! And what are you looking at?!'

'What a weirdo.' Zenitsu thought sitting in the other side of the train; 'Also, Y/N looks so cute while eating!'

"Flame breathing has a long history! In all ages, flame and water hashiras have been among the hashira! Flame, water, wind, stone, and thunder are the basic types of breathing, the other types of breathing branched out from those, for example, mist is derived from wind!"

"Xhat" She pauses to swallow the food on her mouth. "phew, that makes me remember, Shinaguzawa said something about my breathing being weird, do you happen to know anything about seraphic breathing?"

"… Nope!"

"I figured out." She says, her mood immediately dropping. 

"B-But, since it doesn't look like it's derived from any of the current existent breathing, it might be a special one!" Rengoku says in a flustered attempt to raise her mood.

"I see!"

Though, “special” might be a little exaggerated, there was no doubt it was a mysterious one.

There wasn't any mentions of “Seraphic breathing” in the manga, and though it could be just a breathing she accidentally created like all the other protagonists in isekai fanfics do, she had a feeling it was more than that.

Besides, a breathing that was strong enough to make a civilian be able to decapitate a lower moon seems too OP for it to be branched by the other types of breathing.

"Mizoguchi, what color is your katana?" Rengoku suddenly exclaim, making Tanjiro jump.

"?! My name's Kamado! And it's black!"

"Black, huh? Ha ha ha! That's rough!"

"Rough?"

"I've never seen a swordsman with a black sword become a hashira! And I hear they don't know which line to master!"

He then turns to Y/N.

"What about your sword Y/N?"

"How did you get her name right and not mine?!"

"Well….it's kinda hard to explain, it's blue, but also white?"

"Two colors, huh? That's new! Mysterious sword and mysterious breathing, you are quite the surprising fellow, huh?"

"Haha…" She awkwardly laughed in response.

"But I believe you are not a bad person! The color of your blade represents your breathing, so if it's white, then I believe you are a pure at heart person!"

After he said that, Y/N suddenly remembered all the smut fanfics she ever read and was immediately flustered.

"Oh, we're moving…'' Zenitsu comments.

"You guys will train at my place, don't worry!"

'What a considerate guy,' Tanjiro thought.

"GRAAAAH! WHOA! WOW! IT'S SO FAST!" Inosuke exclaims with his head outside the train window.

"BE CAREFUL! YOU IDIOT!"

"I'M GONNA GO RUN ALONGSIDE! I'LL RACE IT TO SEE WHO'S FASTER!"

"THERE ARE LIMITS TO STUPIDITY YOU KNOW!!"

"Better not! We still have no idea when the demon will appear!"

"Huh?" Zenitsu, who was still holding on to Inosuke turns to look at Rengoku with a shocked expression.

"NO WAY! A DEMON IS ON THIS TRAIN?!"

"Yep!"

"IT IS?! GYAH! WE ARE NOT TRAVELING TO IT?! IT'S HERE?! GYAAH! I'm getting off!"

"Over 40 people went missing in this train! They sent some swordsman, but they all went silent, and that's why I'm here!"

"OOOH! THAT'S MAKE SENSE! BUT I'M STILL GETTING OFF!"

"Allow me…to inspect your tickets."

The conductor says with a pale expression.

☆

Honestly, how didn't they notice how suspicious this person is? He's literally walking like a zombie or something.

"?? What?" Tanjiro asks, confused. He's so cute when he acts like a country bumpkin!

"The conductor is going to check our tickets!"

"Enjoy your trip."

Rengoku's face suddenly changes to a serious expression as he gets up from his seat, shielding the conductor.

"Look out! Get back! This is an urgent matter, so don't mind the sword!" He says while looking at the ugly demon across the corridor, the passengers looking at it in horror.

"A blood demon art was hiding this huge thing, and it was hard to sense it! However…if you bare your fangs at innocent people, my bright red flame blade will burn you to the bone!"

Rengoku advances is his direction in great speed.

“Flame breathing, first form: Unknowing fire!”

The demon is then easily decapitated.

"Wow! Awesome swordsmanship! Please make me you apprentice!" Tanjiro exclaims.

"Sure!! I'll make you a strong swordsman!"

"Me too!"

"And me!'

"Ah! Me too! Me!"

"I'll look after you all together!"

"Your big brother Rengoku!"

"Bro!!"

♡

After they all went back to their seats, I could feel my eyes starting to get heavy.

'Wait! Tanjiro is going to dream about his family, right?'

"Tanjiro!"

"… Huh…what…is it?" He drowsily asks.

'Oh, right. I can't tell him what's going to happen.'

"It's nothing..... It's just…good luck, ok?" It was the last thing I said before my vision turned black.

Are you ready?