Clear moonlight spilled like liquid silver across the ground.
Whoosh!
A sudden gust of wind stirred, and a petite figure darted swiftly through the forest.
Raven-black hair flowed like ink, her haori fluttering, her slender waist graceful. The breeze lifted her sleeves, the butterfly haori unfurling in the air like a butterfly dancing.
Yet this beautiful girl's face was etched with anxiety and panic.
The girl was Kochou Shinobu, Kochou Kanae's younger sister—her blood sister!
At dusk, Shinobu was tending to the wounded at the Butterfly Mansion as usual when a black Kasugai Crow swooped from the sky, bearing news that shook the entire Demon Slayer Corps.
"Kochou Kanae has encountered Upper Rank Two!"
Upper Rank!
An Upper Rank demon!
The Corps hadn't slain a single Upper Rank in nearly a century. Records left by predecessors objectively detailed their terror.
Heart ablaze with urgency, Shinobu couldn't wait for backup to assemble. She rushed from the Butterfly Mansion, racing nonstop toward where her sister faced the Upper Rank.
Their parents were killed by a demon before Shinobu's eyes, leaving her trembling and sobbing in her sister's arms. The current Stone Hashira, Himejima Gyomei, arrived just in time, slaying the demon and saving the sisters.
Since then, the two relied on each other.
After their parents' funeral, Shinobu and her sister sought out Gyomei, begging to join the Corps.
The sisters trained together, practiced side by side, and grew as one.
Her sister was Shinobu's only remaining family in the world!
Her only family!
Her most cherished person!
In the original future, after her sister's death, Shinobu even molded her personality, smile, and mannerisms to become "her sister."
That showed the depth of their bond.
Sister… please, please!
You have to be okay!
Nearing her destination, Shinobu gritted her teeth, stomping hard on a tree trunk. Her petite frame shot forward with the recoil, trees blurring past, until she burst from the lush forest.
"Sister! Sist—!!!???"
Her frantic shout cut off, replaced by a face full of confusion and bewilderment.
An utterly bizarre scene greeted Shinobu's eyes.
Her sister and two strangers squatted in a circle, poking at a head in the center with Nichirin Blades.
Faintly, she caught cheerful remarks like "Regenerate, regenerate~!" and "Is that all you've got?"
Shinobu's feet hit the ground, her body staggering, nearly losing balance.
The moment she heard her sister's call, Kanae shot up. Shiraki and Reverie followed, all three beaming with delighted smiles.
With deeply synced memories, Shiraki, through Kanae's perspective and emotions, had lived alongside Shinobu as family.
No doubt about it—Kanae's sister was his sister!
"Shinobu, why're you here?" Kanae's smile was tender.
"Hearing the Kasugai Crow report you faced an Upper Rank, how could I stay put… Wait, Sister, where's Upper Rank Two?"
The short-haired girl's face turned serious, the mint-green butterfly hairpin with purple edges at her nape fluttering. She drew her Nichirin Blade with practiced ease, entering a guarded stance.
"Upper Rank Two? Right there!" Kanae stepped aside, pointing at Douma on the ground, half his upper body intact, lower body a pulverized mess.
The once-heinous demon lay face-up, his expression as hazy as mist, lost in some unknown thought.
Pummeled by high-explosive grenades for hours, his body shattered nearly a hundred times, Shirakis weren't sure if he could still regenerate, but Douma seemed to have given up trying.
Regenerating only meant facing more grenades or Shiraki and Reverie's swordplay. Yup, they'd turned his body into a live practice dummy for their drills.
The Gatling and UV lamps, with their faint anti-regeneration effect, stood nearby…
Douma couldn't be bothered to keep healing. Might as well wait quietly for sunrise.
No emotions meant no emotions—fearless or not, he wasn't about to develop a masochistic streak.
"!!!"
Shinobu's eyes widened adorably, scarcely believing her ears. "Sister, what did you say!?"
"This is Upper Rank Two!?"
Her shocked expression and rose-purple eyes brimmed with disbelief.
This youth, tortured to the point of lifeless despair, was the Upper Rank demon who'd killed countless people!?
Douma ignored Shinobu's stunned scrutiny, still gazing blankly at the fading moonlight.
Her cherry lips parted, Shinobu dazedly lifted her head, surveying the hellish devastation around them.
Blood soaked into cracked soil, the air thick with an ashen scent, the ground and buildings looking gnawed by chaos.
It all screamed of an unimaginably brutal battle.
Shinobu knew her sister inside out. As the Flower Hashira, her sister was formidable, but she couldn't have caused this level of destruction.
Was this the power of an Upper Rank?
What a monster!
A chill of fear crept over Shinobu. Her eyes swept the ravaged battlefield, then refocused on the ground.
"But, Sister, why not cut off his head?" Shinobu sheathed her blade, standing with a serious, puzzled look.
Sunrise was near, but without the sun, only beheading a demon with a Nichirin Blade could truly kill them!
"Because he's still useful alive," Shiraki replied with a warm, kind tone.
Shinobu had been observing the two strangers. Now, as Shiraki spoke, her gaze shifted to him.
Blinking, Shinobu was certain she'd never met these two.
Yet the black-haired youth's gentle smile felt oddly familiar, his soft gaze inexplicably like that of an elder.
Shinobu composed herself, asking politely and curiously, "May I ask who you are?"
"Me?" Shiraki glanced at Reverie, a faint smile tugging his lips, then turned to Kanae.
Shinobu froze, her confused, startled gaze darting to her sister.
The moonlight was achingly tender, its dim glow highlighting the girl's delicate features and eyes, shimmering like dew on pink petals at dawn in early spring.
Under Shinobu's ghost-stricken stare, Kanae's slender fingers twirled her hair, a hint of bashfulness.
W-What's going on?
"Ahem, Shinobu." Kanae coughed twice, extending a hand toward Shiraki. "Let me formally introduce you. This is Shiraki, your brother-in-law~!"
BANG!
A bolt from the blue!
Shinobu's mind reeled, as if Muzan had exploded in her brain, blasting her thoughts into a blank void. Her Nichirin Blade clattered to the ground.
She was utterly floored!
"B-Brother-in-law!!?" Shinobu's head snapped up, her pretty face brimming with disbelief, her voice rising to a shrill pitch.
"Mm-hm." Given Shiraki's closeness with Kanae, only two roles fit.
Family or partner.
Facing her little sister, the former was off the table, so… was there even a choice?
Kanae didn't hesitate or waver, her gentle voice firm with resolve.
Mouth agape, the overwhelming shock left Shinobu as if deaf. Like a rusty robot, she jerkily turned her head.
The black-haired youth's kind smile came into view. Now she understood his warm demeanor, but…
Was this really reality?
Shinobu stared dazedly at Douma on the ground, her eyes losing focus.
Could I be under Upper Rank Two's Blood Demon Art?