"Delicious!"

"Delicious!"

"Delicious!"

"Delicious!"

"That quirk of yours is still there?"

The young man with long bright yellow hair with streaks akin to flames had a bright smile plastered as he ate a bento, saying delicious with each bite.

"Ai?" The Flame Hashira, Rengoku laughed, "Have a seat and eat with me."

Ai too out the swords, keeping them on the side, sitting in front of Rengoku with a smile on her lips, "No, thank you. I still remember how you made me say delicious with every bite I took. Eating with you ruins all the fun."

"Hahaha, it's because it's delicious, and we should appreciate good food."

"Ah, there they are!"

"Miss Ai!!" Zenitsu hastily ran over, standing between her and Rengoku, placing the train ticket in front of her, "Miss Ai! I got you the train ticket!"

"Yes, Zenitsu, thank you," Ai's face crammed, looking at his shiny eyes. No one hit on her before, and this was the first time someone put so many advances on her, and she wasn't sure how to reject him in a way he understood; none of the rejections from before worked on this guy.

"Ah, so you three are here as well. Good!" Rengoku laughed, welcoming them.

Zenitsu was about to happily sit down beside Ai when he got a chill on his spine. He looked around, didn't find anyone staring and him, and tried to sit again, only to feel the same chill, even more dangerous this time.

He gulped, "Then I will sit there…."

"Hm," Ai tilted her head in confusion since she was sure that he wouldn't take a hint and still try to hit on her. She let out a sigh of relief when Tanjiro sat down beside her, looking at Rengoku in hope, explaining to him about Hinokami Kagura.

"Nope! Never heard of it!"

"Oh," Tanjiro blankly watched the guy, who crossed his arms, looking forward with that perpetually happy smile, "So that's it, huh?"

"Well, I don't know! This is the first time that I have heard of Hinokami Kagura, but it's still great that your father was able to apply the kagura to fighting! And that's enough of the topic!"

"Is there nothing you can tell us? Anything that gives us an idea?"

"Nope," Rengoku replied as soon as she asked, rubbing his chin, "Say, Ai. I noticed that your Katana doesn't have any color."

"Hm, because I never had them put any color on it?"

"Huh? Hahahahahaha," Rengoku burst in a laughing, "No, it's not that. We didn't teach you everything, so it's our fault. You, Mizoguchi! What color is your Katana?"

"My name is Kamado! It's black!"

"Black, that's rough," Rengoku laughingly said.

"Rough?" Ai confusedly asked, "Does the color represent something in particular?"

"Yes! Red represents Flame, Blue – Water, Thunder – Yellow, Stone – Gray, Wind – Green, Mist – White! As for Black? I don't know what it represents, but no one with that color has been able to become Hashira yet. No worry, I will teach you!"

"Hm," Ai held her sword, wrapping her palm around the scarlet and turquoise helix pattern on the hilt, "Then I wonder why hasn't mine changed color?"

"I have no idea, but you two should study under me, and I will help you become Hashira!"

"Your ticket," The ticket collector who came to check their ticket took a step back when Rengoku stood up, standing protectively in front of him, "Be careful. This is an urgent matter, don't mind the sword!"

"Kyaa!!!!!!!!!! Ahhhhhhhhhhh!!!!!!!!"

"Grr," The Demon, as tall as Rengoku, growled even when it was on his knees.

"Blood Demon Art was hiding that huge thing! It was hard to sense it! However…! My bright red flame blade will burn you to the bone!"

He moved at immense speed, cutting the Demon's head in one go.

"Wow, awesome swordsmanship! Make me your apprentice!"

"Sure, I'll make you a great swordsman!"

"Me too!"

"And me!"

"I'll look after you together!"

"Our big brother Rengoku!!"

"Bro!"

Ai chuckled, watching them play before turning her eyes towards her sword, "No color…yet."

The ticket collector came to check their tickets and punched them, and before she knew it, she drifted into sleep, much deeper than any she had since she came to this world.

Even when sleeping, she felt an arm around her, and she hastily sat up, moving her hand to take the sword, "Who!"

"Uh…um?" Ai tilted her head, looking at the two pairs of eyes looking up at her. Her mother's and her father's.

Her mother removed the hand holding her nose before she pushed her tiny body back into bed and hugged her lovingly, "Did you have a nightmare?"

Her father inched closer to the two, kissing her head, "You still have time…you should rest a bit longer."

"Papa…Mama?" Ai touched her throat, feeling that her voice had changed when she looked at her hand, much tinier than before.

"I am back…? To a time much earlier….?"

"I told you not to read her so many books; now her brain has stopped working!"

"Oh please, my daughter's brain never worked, to begin with; she is a glutton for stories," Her father chuckled, ignoring that she was right there.

"I am right here, bad Papa!" Ai turned to bite his cheek, but he covered her mouth before she could.

He rested his forehead on her head, "Stupid girl, you have grown so much, and you still act like a child."

Ai widened her eyes, and her mother disappeared, or the illusion of her did. Her tiny body turned back to her teenage one, with her head buried in her father's chest, "Papa…?"

"Hm?"

Ai closed her eyes, clutching onto his clothes, "Did you finally have the guts to see me?"

"No way," Her father chuckled, "It seems that you were caught in a Demon's power and were being seduced by your sweetest memory."

"Then you…?"

"It's the burden of being what I am…even if it's an illusion of mine, created in another world…I am aware of it, and I can take over if I am aware. Pretty crazy, huh?"

"Wait…does that mean you are in my…Memory Palace?" Ai wanted to sit up, to look at him, but he held her down, not wanting to see her or even look her in the eye.

"No, your Memory Palace is the memories of the Past. I can only interfere in the present, so memories or imagination doesn't work."

Ai tightened her jaw, "Then can you tell me why this was necessary?"

"Adversity builds character; it's a simple truth," Her father whispered, "Something necessary for you and your siblings."

"Why?"

"Because the power you hold…without character…without understanding…that power will influence your mind, twist you, and you'd be a slave to it before realizing it. That is how dangerous they are. This trip, if you succeed, you will hold it in the palm of your hand, unimaginable power, if not? You'll die."

"You mean I'll come back home?"

There was a chuckle that caused dread to spread through her body.

"Come home? If you don't master it, Sweetheart, you'd be nothing more than a weak carrier with unimaginable power, shining brightly. In the infinite worlds, your fate would be brainwashed, enslaved, broken, killed and enslaved, or sealed in a weapon used to empower it. In no scenario would you be above a tragedy. And that is with me doing my best to protect you…it's better if you are dead."

"Papa…" Ai gazed down, "You are the worst…."

"I know…now wake up so I can go back to being by your mother's side, who is waiting for you."

Ai felt a jolt go through her body, and her eyes snapped open. She took in her surrounding, watching everyone sleep, with their hands tied to another human's, who was sleeping beside them, with one sleeping beside her.

She watched them, but her motivation was down in the dumps. You'd think that the thought of death would be more motivating, but it wasn't.

She rested her head against the glass, looking outside at the moving picture, "You are the worst liar…Dad."

She wanted to say she knew he was lying because she believed him, but there was something more, something about his words that rang true.

It made her wonder for one moment, what if Muzan got hold of her blood, body, or anything that made him evolve further? What if he got the power that her father said was unimaginably strong and ran to other worlds to spread his army of demons and tragedies. That thought scared her.

Let alone the way he talked, there were so many words that he didn't say, but she felt like she heard.

Like when he said that she would be a weak carrier without control over her powers, shining brightly. It was as if she could hear it, him telling her that her power could be sensed across the worlds to those with enough perception, and if she stayed the way she was, it would bring a disaster.

Even if she managed to fall in love, marry, or do everyday things like those, make a family, all she'd do was bring a disaster to them.

Or the time when he told her, even if he tried to protect her with all he had, he couldn't. Not because he wasn't strong enough, but because he couldn't be there every moment with her. Even if he were, it would be no different than being trapped or enslaved; it was better to die than live a life like that.

Ai chuckled lightly, "I'd probably try to escape…trying to fool Dad and end up dead. I'd probably be one of those characters that are part of the main character's tragic story, defeated by the villain, stolen powers, and killed, and then Dad would probably say something like this to the villain."

"How dare a useless piece of trash to use the powers of my daughter in a way like that or something like that and kill the villain, avenging me," Ai sighed, "So uncool…I don't want to die like that…but I don't wish to chase after the power for the sake of power either."

"Power…what am I going to do with all that power, Dad?" Ai stood up, picking up her broadswords and putting them on her back and waist.

She walked out, looking towards left and right, looking up towards the train's roof, when there was a clang that got her attention.

Ai looked over her shoulder towards the girl she had almost forgotten about, standing in front of her, barely reaching her knees, watching her with big eyes.

"Nezuko…"

Nezuko tilted her head, watching Ai, who knelt in front of her, patting her head with a smile, "Take care of them, ok? I'll be right back."

Nezuko blinked, repeatedly nodding, rushing towards the four, and Ai started walking out, leaving the compartment.

She went out the door and jumped up, rotating in the air before landing on the roof. Her eyes landed on the young man in his mid-twenties, with average height, pale skin, and ringed blue eyes that turned sharply towards his cheek.

There was kanji of Lower One in his left eye, which made her decide to stop and take a sharp breath, "Wood Breathing Technique. Total Concentration: Constant!"

"Oh, you are awake? And ready to fight as well? Well, good morning. You should have stayed asleep."

"Lower Rank One…." Ai whispered, glancing towards the train. Her Wooden Dragons came out of the land, and this train was all metal, moving at a fast speed. Even if the Dragons caught up, at the point of contact, they would lose power, and that meant she was fighting against someone who might be more potent than her at a significant disadvantage unless she could flip the situation.

"Wood Breathing: Second Form – Dragon's Hold!" Ai pierced her sword forward, and a Dragon rose from the ground, speeding on the side of the train.

"I was showing you such a good dream; you should be thanking me, and yet you do this?"

Ai smiled, "It was a good dream…because of it…I got to see Daddy again…so thank you."

The Demon's face contorted as if he loathed to see the happy expression on her face. With a mouth on the back of his palm, he raised his hand, with a mouth on the back of his palm, 'Blood Demon Art…Whispers of Forced Unconscious Hypnosis.'

"Go to sleeeppp!!!" The mouth spoke about to activate its power when the Dragon hastened the speed, biting the arm off to wrap itself around the Demon.

"As if this would-!" Enmu, the Demon, was about to use his physical strength to destroy the Dragon when he felt himself weakening.

"I didn't use it on Shinobu," Ai lightly said, covering the distance between them, "But the Second Form doesn't just trap the opponent; it also drains their strength, energy, and vitality. It's the perfect prison unless my opponent is stronger than me."

She slashed the Cursed Sword to cut his head but stopped right before she separated his neck, "Say, if you got the chance to become more powerful, then what would you use that strength for?"

Enmu tilted his head with a bizarre look, "Why? Of course, to make humans contort their faces, to gaze upon someone struggling with grief and suffering is so much fun! Why else would I seek power?!"

"It's that simple…huh," Ai slashed her broadsword, cutting Enmu's neck, "Then…I wonder if wanting it so that I can be happy…is selfish?"   

"Hahahaha, of course, it's selfish! Say, why don't you become a Demon too?!"

"Hm?" Ai looked up, seeing its neck stretch like a snake, attaching itself to the head, swelling more and more.

"You want me to tell you why I didn't die when my head was cut off? It's so simple-?!"

"Of course, I know; it's not your body," Ai dragged the tip of the sword against the train, "For a while now, I have been sensing a life force in this train. I was wondering how to deal with you while saving the hostages."

She scratched her cheek, "Although, I didn't manage to come up with a single one."

"Ahhahaahaha, then I will eat the food while you try to figure it out."

Ai watched him but didn't follow since she felt Tanjiro wake up, so he and Nezuko should be able to handle the Demon for a few moments. She needed to come up with a plan to defeat the enemy.

"If only I could use the other Breathing Techniques, but they don't have enough strength to get through the defense of Lower Rank 1…." She jumped inside the train, glancing toward Nezuko, smashing through the tentacles, and her eyes widened in realization.

"Mm? It divided itself, which means," Ai let go of the Wood Breathing, using the Thunder Breathing, "Reverse Thunder Breathing! Second Form! Chidori Stream!"

She plunged the broadsword into the train, and a stream of Chidori spread out at the center of the train, falling on the tentacles, avoiding the passengers.

"Nezuko! Don't get overwhelmed!"

Nezuko clenched her fists, nodding with determination, "Mm! Mm!"

Ai smiled at her and rushed to the end of the train. Even though she knew that the Lower Rank was probably in the front, "Thunder Breathing: First Form! Thunderclap and Flash!"

She cut all the tentacles in this one and moved to the next, using Thunder Breathing and Reverse Thunder Breathing in tandem until she reached the last compartment.

While she was jumping between the second last and the last compartment, separating the two compartments. She stepped inside, "Reverse Thunder Breathing! Second Form! Chidori Stream!!"

She cleared the body parts of the enemy before she plunged the sword down, stopping the train's speed massively, using the technique, "Stone Breathing: Second Form! Rock Prison!!"

Rocks rose from the ground, covering the last compartment, raising it, covering the whole compartment. It abruptly came, but nothing much happened except the sleeping people falling forward.

"Oh wait, I didn't plan how to get out," Ai was stunned, laughing to herself, "Oh, that was stupid."

She let out a long breath, looking up to see if he restored himself, but it was as she thought; he didn't

When she knew that he merged with the train, she assumed it must be in the front or back. The front made good sense if he wanted to control the train and the back to hide.

So she returned to either find him or reach the farthest point of his control.

If she destroys it and then separates the compartment, he shouldn't be able to reach over here again.

Ai broke the wall, seeing the train much farther away, "Thunder Breathing: First Form! Thunderclap and Flash!"

She blitzes forward, taking the sword and stepping inside the compartment to find Rengoku flashing, killing everything in his way, "Rengoku! I leave this one out!"

"So you cleared one?! Good! Seven more to go!"

"Yes!" Ai blitzed behind Rengoku when he cleared the train, getting rid of this compartment. But this time, she created these breakable walls in front of the train and dug her sword deeper, slowing it down before locking it in the rock prison, leaving a hole from which she left.

She barely managed to clear it when the train jumped up, and its compartments were filled with flesh, "Gee, guys. You didn't have to work so fast. You could have waited for me and let me clear more of the compartments."

She glanced towards the scarlet and turquoise threads, getting sewn in the hilt, "Hm. I wonder who killed you…those guys…they are getting stronger at a blinding speed."