It was another peaceful day in the Butterfly Mansion. Tanjiro and his friends were quickly finishing up with their training, finally able to beat Kanao in every exercise and master Total Concentration Breathing. Aoi was still getting used to her new rank as Hashira, training extra hard alongside her sisters in order to be more proficient at her job (well from what Rui has seen it looks like she's trying to develop a breathing style of sorts). Everything was going well for the group..until....

"Alright Rui, we're going on another mission!" Tanjiro excitedly exclaimed as he walked through the door.

Rui groaned. He's already been on one this week, why are they sending him out on another.

'Perhaps they enjoy tormenting me for my past sins,' Rui thought as he looked up at Tanjiro from his futon.

"I'm sure the mission won't be that bad," Tanjiro smiled as he sat the box down, Nezuko instantly shrinking down and crawling inside it.

Rui gave Tanjiro a deadpan look, "I highly doubt  that."

"But Rui, we get to go on a train! A train!" Tanjiro said in an excited tone.

"Trains aren't all that exciting," Rui responded. He's been on one before, just a few days ago alongside the butterfly sisters. He wasn't particularly amused by it (of course he was, it was one of the best experiences of his life), but why is Tanjiro excited about aborning a train is beyond his own understanding.

"Sure they are," Tanjiro responded back.

"Clearly you've never rode in one before," Rui stated. He knew that Tanjiro and Nezuko's family was poor, he's heard the chestnut-haired boy tell his friends about his life before becoming a demon slayer. This was going to be an exciting moment in both the siblings' lives...even if one of them will be asleep for most of it.

Tanjiro nodded, "I'm sure they're not that bad."

Rui shrugged, "Depends on who you're with, though I don't know why people are going missing on one. Must be the work of a demon if I had to guess."

"Mhm, that's why we're going on this mission together!" Tanjiro responded in an optimistic tone.

Rui rolled his eyes, "Curse your optimistic attitude on life."

Tanjiro smiled as he gestured for Rui to get in the box, "You'll get used to it."

"Bet," Rui said as he shrunk down and slowly climbed into the box, "When this mission is over with I would like some alone time...god knows I'll need it after putting up with your annoying ass friends."

Tanjiro nodded as he slowly closed the box, "Don't worry, I'll make sure you get some alone time after this."

"Thank you, Tanjiro," Rui responded as the box closed shut.

"No problem, Rui," Tanjiro smiled as he picked up the box and placed it on his back.

—

"Hey! Hey! Hey!" Inosuke stared up at the train as it blew its whistle, "Wh-What...What the hell is this creature? I bet that this thing...the lord of this land...the ruler of this land..."

Inosuke ran down the platform and continued admiring the train, both Tanjiro and Zenitsu standing right beside him, "See how long it is? So intimidating, no mistake! It looks like it's asleep now, but don't let your guard down!"

Rui rolled his eyes from inside the box. Clearly that boar-headed guy couldn't tell the difference between a train and mountain beast. What an idiot.

Zenitsu looked at Inosuke with a deadpan expression on his face, "It's a train, dumbass. Don't you know what a train is?"

Inosuke immediately shoved his hand in Zenitsu's face, "Shush! Calm down! It might awake! I'll lead the charge and destroy it, you guys evacuate people from here!"

Inosuke immediately grabbed onto his blades, staring up at the train ready to attack. Tanjiro stared at Inosuke with a stern expression on his face. He didn't expect Inosuke to react this was, much less be willing to pull out his blades in public.

"Wait, Inosuke!"

Inosuke turned around and looked at Tanjiro, "What?"

"Didn't you know it might be the guardian deity of this land?" Tanjiro asked him in an attempt to calm Inosuke down, "You never know. Also you shouldn't attack all of a sudden, it could bring bad luck upon us."

'Seriously, are they both stupid?' Rui thought, 'Even I can tell the difference between a train and some stupid guardian deity! How the hell did these two even become demon slayers?!?'

Zenitsu glared at Tanjiro as if he was stupid, "Didn't you just hear me tell Inosuke it was a train? Do you not know what a train is? It's a vehicle for transporting people long distances, you country bumpkin."

"I know what a train is, Zenitsu. Wait...is this what the crow was talking about earlier?" Tanjiro asked Zenitsu. He was confused.

Rui internally groaned from inside the box, 'Yes that's what the fucking crow meant by 'train', you dumbass! God you're so stupid!'

Inosuke walked off from the group and immediately turned around and was charging head first towards the train, instantly head butting it. Zenitsu reprimanded Inosuke for his action, stating that he is embarrassing both them and the Demon Slayer Corps. Rui couldn't help but agree with that statement inside his head despite not being able to see from outside the box.

'God these guys are stupid.'

"Hey, what are you three doing?" A train conductor shouted, "Help! Someone call the police!"

"Not good! Not good! Not good!" Zenitsu shouted as he grabbed Inosuke by the neck, "Run!"

Both him and Tanjiro immediately started running, Zenitsu dragging Inosuke by the heck while Tanjiro gripped onto the box tightly. Eventually they hid in a nearby alleyway, Zenitsu sitting Inosuke down and yelling at him.

"Thanks to you, we went through hell and almost got caught by the police! Say you're sorry!"

"Huh?" Inosuke exclaimed, "Why the hell did we have to run in the first place?

"The Demon Slayer Corps aren't officially recognized by the government. We can't just walk around carrying our swords openly, it's against the law. Besides, they wouldn't believe us anyways when we tell them that demons exists...even if Tanjiro just so happens to be carrying two in the box," Zenitsu explained.

Rui was deciding on rather or not he wanted to get out of the box and slap Inosuke across the face. Clearly he never grew up in a civilized society much less have a basic understanding of how the law works. Dumbass.

"Even if we work so hard to protect them they wouldn't believe us?" Tanjiro asked him.

Zenitsu sighed, "Well that's just how it is. For now let's just hide our swords behind our backs and pretend to act normal..."

Inosuke chuckled, immediately striking a pose as he shows both Tanjiro and Zenitsu where he put his swords at.

"We can still see them, Inosuke. Put a damn shirt on," Zenitsu said in a deadpan tone.

The train whistle startled the trio out of their conversation, Zenitsu immediately freaking out as he sees the train leave the station. Inosuke immediately sprang into action, running towards the train and hopping onto one of the nearby exits. Tanjiro immediately followed after Inosuke, Zenitsu running close by and shouting for the duo to hold on.

Tanjiro hopped onto the nearby exist beside Inosuke, quickly helping a struggling Zenitsu get up onto the platform and looking at the sight in front of them. It truly was a magnificent sight to behold.

Zenitsu tapped Tanjiro on the shoulder, looking at him with concern in his eyes, "Tanjiro, are you sure it's alright for Nezuko-chan to come along? Wouldn't the Demon Slayer Corps headquarters be the safest place for her (and the wretched spider demon, Rui)?"

Rui internally flicked Zenitsu off. Both he and Nezuko are perfectly fine for this mission. As long as they don't run into a Kizuki (which Rui most certainly knows they will), they should be fine.

Tanjiro gave Zenitsu a reassuring smile, "I'm sure they'll be fine. Both Nezuko and Rui are capable of handling themselves, so there's no need to worry about them."

'I'll take back my previous comments from earlier; you're not entirely a dumbass,' Rui thought as he smiled at Tanjiro's comment. He's taken on stronger demons before, so there's no need to worry about rather or not he's capable of handling himself in a fight. As for Nezuko...she's certainly on par with him in terms of strength (even though she just recently awoken her blood demon art). Rui's 100% sure she can handle herself in a fight.

Zenitsu smiled at Tanjiro's response and turned his head towards the sky. Memories from their pasts entered their heads. Tanjiro smiled determined, ready to take on whatever challenges coming his way.

'Nezuko...Rui...I promise whatever challenges comes our way we'll overcome them...and hopefully one day we will bring an end to Muzan Kibutsuji's reign of terror...once and for all.'