The wilderness lay silent under the full moon. Silver light spilled across the forest floor, revealing the grim scene before a young man crouched among the trees.
"Where… am I?"
The young man, Lock, slowly opened his eyes. His sharp gaze swept the clearing, taking in the stench of blood, the bitter wind, and the scattered bodies of Demon Slayer Corps members. Faint cries echoed through the forest, chilling him to the bone.
Something deep inside him stirred. A strange awareness, almost instinctive, pulsed through his mind. He realized, with a shock, that he had transmigrated into this world—another time, another place, filled with demons and death.
Every detail became vivid: the slight rustle of leaves, the patterns of shadows, even the smallest movements in the distance. His senses sharpened beyond normal human limits.
Lock's thoughts raced.
Nada Spider Mountain… Lower Five territory… This is dangerous.
He was unarmed, inexperienced, and alone. If a demon appeared… survival would be unlikely. He pressed himself against a tree, hoping to creep and remain unnoticed.
But luck was not on his side.
A low, wet chuckle came from the shadows behind him.
Lock's heart sank. "Not now…"
A grotesque demon emerged, its face twisted into a hideous grin, saliva dripping from its fanged mouth.
"Hungry… you smell delicious…"
Despite the terror, Lock's mind remained sharp. Some instinctive insight surged within him, giving him clarity about the demon's movements and intent. His body reacted almost instinctively.
Watch its teeth… anticipate its strike…
In that moment, a strange rhythm of breath and heat rose through him. Without fully understanding how, he instinctively formed a New Breathing Style, at least the core of it, in his body burning with strength and speed he had never known.
The demon lunged for him, but Lock twisted aside with unnatural agility. He felt stronger than he ever had before.
Then, from the treetops, a figure descended gracefully, light as a butterfly.
She wore the uniform of the Butterfly Estate, a patterned Nichirin sword at her waist, and delicate butterfly hairpins in her hair. Long black hair tipped with purple framed her face. She moved with inhuman speed and elegance.
Shinobu Kocho, one of the nine pillars, had arrived.
In an instant, she was beside Lock. Drawing her blade with dazzling speed, she struck the demon with precision.
"Breath of Insects: Dance of the Butterfly – Teasing!"
The poison from her sword coursed through the demon's body, and it collapsed instantly.
Shinobu landed beside Lock, her butterfly cloak fluttering softly. A faint floral scent surrounded her.
"Moshi moshi… are you alright?" she asked, violet eyes bright.
Lock nodded, though exhaustion weighed on him. "I'm… fine. Just… my mind's overwhelmed."
She leaned closer, noticing a strange black pattern across his chest.
"Stripes?!" Her smile faltered. She recognized it: a sign of extraordinary potential, enough to multiply one's combat ability.
But Lock… he wasn't a Corps member. He was an ordinary human. Yet he bore the stripes.
Shinobu's mind raced. He could become extraordinary… maybe even a future pillar. She wouldn't risk leaving him here alone.
Regaining her composure, she smiled sweetly. "What is your name?"
"Lock," he replied.
"Lock… do you have a home?"
"No… I'm an orphan."
Her expression softened. "Most members of the Corps are orphans. Why not come with me? You could train safely and learn to fight properly."
Lock considered it. His instincts and newfound Breathing Style would benefit from proper guidance. And the Demon Slayer Corps offered both safety and the chance to grow.
"I'll join the Corps," he said.
Shinobu laughed, a musical sound. "Good. Then come with me to the Butterfly Estate. You must be exhausted from that fight."
Lock nodded—but as he stood, the strain of intense awareness and rapid comprehension overwhelmed him. His legs wavered, and he collapsed into Shinobu's arms, unconscious.