Kocho Kanae couldn't put her finger on anything suspicious about the girl who'd appeared so suddenly before her—and yet something felt off... call it a vague, inexplicable intuition, the kind that stirred hesitation in her at just this moment.
What would Inori think? How does she regard this little sister? And why has she never once mentioned her?
"What's wrong, Nee-san? She seems pretty good to me."
Kocho Shinobu kept pressing her. In her eyes this was a plan good on both counts—recruiting talent for the Demon Slayer Corps while also being a chance to learn more of the things Inori refused to tell the two sisters.
"It's nothing."
Kocho Kanae shook her head. Turn it over as she might, she couldn't arrive at a good answer, so she decided to let it go.
She studied Ouma Mana's face... and gradually it overlapped with the Inori in her memory. The resemblance alone made Kanae feel an immediate sense of closeness, and there was no real reason not to accept her.
"Mana-chan, from now on you'll train under me. I can teach you Flower Breathing."
"What's that? Is it impressive?"
Ouma Mana cocked her head and asked.
"Not especially. But it should help you find your sister~"
"Okay."
"Then from now on, you're my teacher."
Though deeply reluctant, Mana still stepped back and gave Kocho Kanae a simple bow to acknowledge her as her teacher. Kanae was no hidebound traditionalist and cared little for formalities. She turned to Kocho Shinobu and added:
"Take Mana-chan to where Inori used to stay. I'll go report this to Oyakata-sama."
"All right, Nee-san."
...
...
Playing a role like this was a challenge for her, and once the setup was established it couldn't be casually broken. But for the person she loved, suffering this little bit was nothing at all.
This was the plan she and Inori had settled on in advance. They say the most dangerous place is the safest—so if the safest place for Inori, as a demon, was Infinity Castle, then for Mana, a human, the safest place was of course the demon slayers' own home.
The instant a face like hers was spotted by the Demon Slayer Corps, it would draw suspicion. Rather than wait until she was discovered and found herself unable to explain, it was better to make the first move and "defect" voluntarily.
The Demon Slayer Corps might not be much of a place. They had far too many flaws. It was absurd that in a new age like this they still clung to so many traditions long overdue for the scrap heap—like the rule that a teacher must commit seppuku in atonement if a disciple turns into a demon. Since no one wants to die, when faced with the overwhelming fear of death, there was no telling what mad decisions anyone might make.
But thankfully, the current Oyakata-sama, Ubuyashiki Kagaya, was a wise man of firm principle who saw good and evil clearly. So long as Inori showed sufficient resolve, they were certain to accept her. And with the lesson learned before, he wouldn't again let that hot-tempered Wind Hashira run wild the way he had.
Most important of all: Ouma Mana was Inori's little sister.
And who was Inori? The new Demon King who had killed Kibutsuji Muzan. Kanae's presence had already made the Corps' relationship with Inori a complicated one—there was no need to take the risk of falling out with her over this. Moreover, the demons under her command were far better behaved than in Muzan's era, a situation everyone wished to see.
"What did your family—yours and Inori's—do before?"
Kocho Shinobu led her onto the familiar little courtyard path, unable to quite hold back her curiosity.
"Mm... officials, I suppose."
Mana's father, Ouma Kurosu, was a scientist; her mother had died in a difficult labor after being infected by a virus. Both had held important posts of a kind, wielding a certain power. Put that way, it wasn't wrong.
"Though now, they're both gone from this world."
"I see..."
Today the sky was especially clear, the air clean and pure. Under that deep-blue sky the Butterfly Mansion greeted another fine day. Ouma Mana suddenly stopped, drew a deep breath of the sweet air, her gaze seeming to stretch to some higher, farther place in the heavens. In the days to come, Mana would no longer be a lonely, solitary soul—she now had a means of interacting with this world: a real body.
—Inori-chan, I'll definitely grow stronger. Strong enough to protect you.
Had Inori been able to hear her, Mana would never have said anything so embarrassing and handed her ammunition to tease her with later. But she was asleep now, and before she woke, Mana would give it everything she had to guard their promise.
—No matter what future lies ahead, we'll always be together, never to part.
...
...
Kamado Tanjiro was a boy born into an ordinary farming family, a household that had sold charcoal for generations. As the eldest son, though only thirteen, he'd long since begun going out to sell charcoal in place of his sickly father, to keep the family fed.
In the deep, snow-blanketed cold of winter, the boy trod through the snow as always, a wicker basket heaped with charcoal on his back.
Each step onto the thick snow cost that much more effort, but Tanjiro didn't mind in the slightest—if anything, he saw it as a valuable opportunity to train.
"Fuu..."
The boy felt the cold and stopped to rest his feet a while.
He'd walked this road more times than he could count, and home was already close at hand. A short rest first would do no harm.
Snowflakes clung to the boy's lashes. He breathed out a few puffs of warm air... and lifted his head to glance at the dim sky.
The heavy snow showed no sign of stopping. The last of the dusk dissolved, night fell, thick snow-clouds curtained the sky so that not a single star could be seen—all the more chill for it. The silent darkness around him made him uneasy.
—Better get back soon. I promised to help Nezuko wash the little ones' clothes today too.
He shook his head and drew in a deep breath of the snow-laced cold to sharpen himself, then made to press on—but he'd taken only a single step before he stopped, unable to help it.
—Something seems to be squirming in the snow up ahead.
Tanjiro felt both nervous and curious, and in the end he couldn't resist drawing closer. He brushed the ice and snow aside with his hand and saw a... strange creature, roughly the size of a fist. It was soft and sticky, a layer of snow clinging to its skin, and the faint shudder of its body proved the thing was alive.
Unable to hold his curiosity in check, Tanjiro reached out and picked it up, cupping it in his hands, slowly scraping the snow off its surface, then breathing warm air onto it a few times to warm it back up.
"Is this... some kind of egg?"
Suddenly, an ominous cracking sound rang out.
The unknown object cupped in the charcoal-selling boy's two hands abruptly split open along a fissure, and from it spurted several drops of scalding blood. The boy hurriedly threw up a hand to shield himself, so startled by the shock that he nearly flung the thing away outright... At the fissure's edge fresh blood was flowing, and dimly he could make out some white substance within—deeply revolting.
He thought the little thing was pitiable... it was a life all the same. But Tanjiro was still young; he couldn't fathom what kind of creature this actually was. Perhaps the fabled "snow insect"?
And yet at that very moment, the "snow insect" in his hands suddenly shot up out of his palm at an unimaginable speed, its round body turning into a straight, spearing blade that shot straight into Tanjiro's face and burrowed inside his body.
An indescribable chaos swept through the boy's whole frame. He fainted on the spot, collapsing into the vast expanse of snow, dead to the world.