Tanjiro's father was sickly; it was unknown if this was congenital or due to too many years of training in Sun Breathing.
However, he possessed something no one else did: the Transparent World. When facing a giant bear several meters tall, his breathing remained completely steady, and he could slay it with his eyes closed.
Tanjiro's father usually lay at home resting like a plant, only lighting a bonfire and performing the Hinokami Kagura Dance all night every winter.
When Tanjiro was little, he asked his father why he was so frail but could dance all night in the bitter cold without issue. Tanjiro's father told him that the Kagura Dance was inherited from his grandfather, and when he was younger and healthier than now, he would still be out of breath performing it.
Later, he understood that the key lay in the breathing method and the precision of the movements. After realizing this, he worked hard to adjust his movements and breathing correctly. Then, one day years later, a Transparent World suddenly appeared in his mind.
This was precisely the 'domain' that only those strong enough to exhaust their last ounce of strength in painful struggle could comprehend.
"It was only much later that I understood that when Father took me with him to kill the bear that night, he wanted to teach me the secret of the 'Transparent World' he saw…" Tanjiro sighed after explaining everything.
"Unfortunately, my father passed away less than ten days after that night, and I was too dull to comprehend that 'Transparent World.'"
Uchiha Nagi and the Flame Pillar quietly listened to Tanjiro recount his family history. However, Uchiha Nagi suspected that Tanjiro's father did not die from exhausting his potential killing a bear, but because Tanjiro's mother was too beautiful.
Just look at the good looks of Tanjiro and Nezuko, his sister. He married a beautiful wife, then tilled the fields day after day, producing a large number of children. He was already frail, yet he worked so hard tilling the fields; it would be strange if he didn't die young… Oh, and they lived on a mountain, not as landlords. The entire family's food and drink relied on a sickly male head of the household. Tilling fields and chopping wood by day, tilling fields and making babies by night—it's no wonder he died early… Kyojuro Rengoku, upon hearing Tanjiro mention the Transparent World, realized it was very likely the Transparent World, and the Flame Pillar became incredibly excited. As the straightforward and cheerful Flame Pillar, he never beat around the bush. Kyojuro Rengoku, with wide, joyful eyes, said to Tanjiro, "Then—young man, would you be willing to show us your family's Kagura Dance sometime?"
Tanjiro scratched his hair, smiling sheepishly, "Of course, I don't mind teaching the Kagura Dance to Mr. Rengoku, Nagi-aniki (Nagi, older brother), and Inosuke. I'm just not too sure if the Kagura Dance is related to the Transparent World Nagi-aniki (Nagi, older brother) mentioned."
Uchiha Nagi earnestly said to Tanjiro, "Thank you, Tanjiro, I really want to learn your family's Kagura Dance."
Lying to Tanjiro in front of him wouldn't work. It was better to be honest. He had a divine sense of smell and could detect human emotions. He could sniff out lies and truths with his nose, truly an unscientific nose… "Tanjiro~ How could you forget me, boo hoo hoo… Don't you want me anymore?" A yellow shadow instantly pounced, hugging Tanjiro's leg and crying hysterically. It was Zenitsu.
"Zenitsu~ Don't do that, it's too embarrassing. We'll all train together; I won't leave you behind…" Tanjiro, annoyed, wiped the snot from his pants.
Seeing this, everyone burst into laughter—
"Hahahahaha…"
— — — —
After a day of travel, the train slowly pulled into the station. The 'Mugen' train, which had just been serviced, was completely wrecked. Fortunately, all the passengers on board were safe and sound.
No, that's not right. A few assassins, who had been lured by the nightmare demon's dreams and possessed dream-hiding abilities, were directly killed by Uchiha Nagi. One of them was killed by the Flame Pillar, who, feeling his body in danger, strangled the opponent's neck. Among these people's mental worlds, Tanjiro's was the most absurd; facing the assassin sent to kill him, his mental world eagerly led the assassin to the core mental area… On the other hand, the abnormal Inosuke and Zenitsu, their mental cores directly turned the tables and played with the assassins like toys, which was incredibly powerful.
On the return journey, they didn't encounter any more demons; the trip was peaceful. Tanjiro's stomach, which had been pierced, was eighty percent healed. Only the Flame Pillar's body still needed to recover from injuries.
After all, that chest-piercing blow was too severe, almost killing him. Even if the external wound healed, the internal injury wouldn't recover in a single day.
Now, Kyojuro Rengoku occasionally coughed a few times because that chest-piercing attack had injured his lungs. Although Uchiha Nagi had treated his lungs several times with Medical Ninjutsu, some lingering internal injuries remained. Ultimately, Uchiha Nagi was only a Medical Jonin, not a top-tier medical master like Tsunade.
"Finally off the train! We can go back to the Butterfly Mansion, that's great" Zenitsu stretched, "Nao-chan, Kiyo-chan, Sumi-chan, I'm coming for you~"
"Then Nezuko will be mine~" Xiao Zhuzhu Inosuke (Little Piggy Inosuke) suddenly shouted this.
"What~ You bastard, Nezuko-chan is mine—" Cowardly and afraid of death, only girls could make Zenitsu never back down.
"Bastard, why do you want so many, are you going to eat them?"
"Pfft pfft pfft, only a demon would eat them, no, I won't eat them~"
"@!#¥¥@~!"
"@!%¥%@…"
"Hey, I say, can't you two stop arguing~" Tanjiro said helplessly.
"Hahahahaha~"
As soon as they got off the train, the group met the member sent to pick them up, Murata, the extra character rumored to have the strongest luck, a man who couldn't die no matter how much trouble he got into.
"Everyone, please get in the car~" Murata smiled.
To accommodate the injured Flame Pillar, the Demon Slayer Corps had sent a car this time. That's right, this world has cars, buses, automobiles, and trains, even guns… The Wind Pillar's younger brother, Genya Shinazugawa, uses a gun.
Of course, aside from powerful explosives and such, bullets from firearms only cause a small hole in them. Aside from severing their necks with a nichirin blade, they have no other weaknesses.
"Oh oh, what a big steel monster, and it runs by itself?!" Inosuke tapped the bus-sized car with his sword… "Inosuke, don't be foolish, don't hack the car…" Zenitsu covered his head and pulled him into the car.
Uchiha Nagi sat in the front, looking at the familiar steering wheel, accelerator, brake, and other controls, and sighed. Although it was very similar, it was ultimately not the world he was born in. Only Tanjiro, beside him, sniffed with his dog nose, curious why Uchiha Nagi felt a sense of nostalgia for the past.