Soon, after Tanjiro introduced himself, Rengoku acknowledged that if Kagaya accepted Nezuko's existence, he would as well.
"Sit down here!" Rengoku invited Tanjiro.
"Why are you here? Is it a mission?" Though Tanjiro sat beside him, Rengoku kept his gaze forward.
"Our Kasugai crow delivered an order. More people have been disappearing on the Mugen Train. We were to rendezvous with you, who was already on the scene." Tanjiro explained seriously.
"I see. Understood." Rengoku nodded calmly.
Tanjiro then inquired about the [Hinokami Kagura: Round Dance], but Rengoku knew nothing of it.
"The history of Flame Breathing is ancient. In every era, swordsmen of flame and water have become Hashira. Flame, Water, Wind, Stone, and Thunder are the foundational breaths. Others are derived from these." Though unfamiliar with Tanjiro's query, Rengoku shared his knowledge.
Soon, in Takeru's carriage, a conductor began checking tickets.
Observing the conductor's guilty demeanor, Takeru said nothing. While tempted to intervene, he knew the conductor acted out of selfish desire… aiding a demon for a pleasant dream, potentially dooming over two hundred passengers...
"Amazing! So fast! Wahaha!" Takeru suddenly heard Inosuke's voice and sighed internally.
"That idiot..." Yukino recognized the voice and facepalmed.
"I'll run outside! See who's faster!" Dragged by Zenitsu, Inosuke tried to jump from the window.
"How can anyone be this stupid?!" Zenitsu felt exhausted.
"It's dangerous. We don't know when the demon will appear." Rengoku suddenly warned.
"What?! A demon's on this train?!" Zenitsu was shocked.
"It will appear." Rengoku stated firmly.
"Seriously?! No way! We're not going where a demon is… it's already here?! Let me off!" Zenitsu panicked, turning pale.
"Tickets, please." As they spoke, the conductor reached their carriage.
Unaware, everyone presented their tickets.
"What's this?" Tanjiro asked curiously.
"The conductor punches a hole after checking." Rengoku explained.
Even Rengoku hadn't detected the tampering or anticipated such a cautious demon.
After the tickets were punched, an ominous aura filled the carriage...
Unbeknownst to them, the Blood Demon Art activated, plunging them into slumber. Their current 'reality' was a shared dream...
"Conductor, it's dangerous here. This is an emergency. Please overlook the swords." Rengoku stood, revealing his blade.
Suddenly, the lights flickered, and a demon appeared. Rengoku instantly used Flame Breathing, First Form: Unknowing Fire, swiftly eliminating it.
Yet, this was merely part of their dream. In reality, they remained deeply asleep.
...
"It's strange. Everyone seemed to fall asleep instantly." As Lower Moon One's technique took effect, all passengers succumbed.
"Indeed. This must be the demon's ability." Takeru replied with a faint smile.
Inducing sleep was advantageous… it prevented panic and interference from passengers.
Through his senses, Takeru detected four children in the frontmost carriage awaiting the Lower Moon demon's orders.
The conductor, filled with guilt, knelt before a disembodied hand with a mouth, tears in his eyes.
"I did as you asked. I punched their tickets, making them sleep. Please let me sleep too, so I can see my wife and daughter again. I beg you..."
"Well done. Sleep." The hand spoke with a bewitching voice.
Instantly, the conductor collapsed, entering slumber.
"What should we do?" The children behind couldn't help but ask.
"Soon, their sleep will deepen. Wait until then. Demon Slayers with sharp senses might wake from killing intent or demonic aura. Be careful not to touch their bodies when attaching the ropes."
"I cannot leave the locomotive yet. Do your best until preparations are complete. Then you shall have blissful dreams." The hand seductively coaxed.
"Yes!" The children nodded earnestly.
Yukino and Sylphin asked Takeru when to act, but he wasn't in a hurry. Upper Moon Three would appear at the journey's end. Eliminating Lower Moon One prematurely might prevent his arrival, which would be a loss.
Time passed slowly. When Takeru sensed the children moving, he opened his eyes.
"It's time. However, this demon can induce pleasant or nightmares, typically through eye contact. Avoid looking into its eyes." Takeru warned seriously.
"Understood." Yukino nodded. She had learned Observation Haki, though not yet proficient, it sufficed for combat.
"Eh? How do we fight without looking?" Sylphin was puzzled.
"You can learn Observation Haki later. For now, just avoid eye contact." Takeru replied calmly.
He then tore a sleeve strip to blindfold himself. Yukino followed suit.
Without Observation Haki, Sylphin couldn't blindfold herself and simply followed.
Meanwhile, in the locomotive, Enmu, Lower Moon One, smiled gleefully.
"To die in a dream is true happiness. Even the strongest Demon Slayers are powerless. The driving force of humans is the heart, the spirit. Destroy the spiritual core, and killing them is effortless. Human hearts are as fragile as glass crafts." Enmu laughed mockingly, looking down upon humanity.
…
"It ends now." Arriving at Rengoku's carriage, Takeru stated calmly.
"Who are you? Why aren't you asleep?" The four children looked warily at Takeru's group.
They held special ropes and spike-like tools.
"Is hiding in dreams forever truly good?" Takeru sighed.
"Shut up! You know nothing!" A girl shouted angrily.
"On the contrary, I know. Your deal with the demon. I saw everything. Though your lives seem tragic, how could you trust a demon to grant you pleasant dreams?"
"I heard it say its greatest pleasure is giving you a pleasant dream before turning it into a nightmare." Takeru shook his head.
Hearing this, the children froze.
"Lies! I'd never believe you!" A girl screamed, lunging at Takeru with her spike.
"Foolish beyond measure." 'Seeing' her move, Takeru sighed, appearing behind them and lightly tapping their pressure points, rendering them unconscious instantly.