The realm of Emptiness is invincible precisely because it is nothingness itself — the highest form of swordsmanship.
For countless generations, swordsmen have longed to reach this peak. Some sacrificed their families to devote themselves entirely to the sword. Others descended into madness and slaughter. Many stripped themselves of all emotion, becoming blades without humanity.
And yet… it is harder than climbing the heavens.
Even the most gifted swordsmen often failed to make the leap from "One" to "Zero." Even Miyamoto Musashi — who wandered across countless worlds, clashed with mighty foes, and refined her swordsmanship endlessly — had never touched it.
To achieve Emptiness is to become a swordsman unmatched in any era.
Though Musashi, with the Heavenly Eye, had once reached the state of "One" — compressing infinite possibilities into a single strike — she knew nothing of the true void.
Not until she was summoned into this world.
The instant she met Shirou Muramasa, she realized: he had stepped into a realm opposite of her own. From him, she sensed the aura of the infinite void.
Their duel confirmed it. From Shirou, she again felt that same nothingness.
Musashi believed that with another ten years of training — of sharpening her blade, her body, her mind into perfect unity — she too could finally reach the void. She even mapped out her training plan.
But fate had other ideas.
With nothing more than a single sugar-like pill, she broke through the impossible barrier from "One" to "Zero." She had reached the void.
…Was something so sacred truly so cheap?
In the hot spring, Shirou Muramasa immediately noticed the shift in her aura. But he wasn't surprised. After all, he had tasted the power of the Efficiency Pill himself.
One pill could accelerate everything — research, combat, comprehension. It could turn an ordinary human into an unparalleled genius of history.
Musashi's breakthrough was no fluke. She already had the talent, the experience, and the foundation of a true wanderer of worlds. Even those swordsmen of old who reached the void had never carried such accumulated wisdom.
But Musashi's path had always been skewed. With her nature, she often chose escape over death-matches. Even with the Heavenly Eye, she had skirted the edge rather than embrace the fatal battles needed to forge belief into emptiness.
She had always been one step short of the void.
The Efficiency Pill erased that step. It let her bypass the life-and-death crucible, uniting her scattered beliefs and lifting her to a higher vantage.
Shirou Muramasa swallowed his own pill, sharpening both body and spirit.
"Draw your sword."
Click.
The blade Dian Guang Wan, born of the sword itself, unsheathed in his mind. Magic surged forth — not of the five elements, but of pure sword-essence.
Every thread of prana was a blade unsheathing, ripping his body apart from within. His circuits were too weak to bear such pressure; sustained release would shred him to pieces.
Musashi felt it instantly. The boy in her arms wasn't flesh — he was countless blades. She might be impaled at any moment.
Her Master was closer to the void than she was — and the price was agony.
"You're still so young…" she whispered, her fingers brushing his cheek.
Where they touched, lines of green light shone — Muramasa's circuits, materialized, piercing her body. Pain exploded within her like countless blades tearing her apart.
It hurts. It hurts. It hurts!
"Musashi, how do you feel?"
His trembling childlike voice reached her. She knew his pain was far greater than hers.
"The void… is a place that severs thought and desire alike. Don't hold back. My Master — just do it."
She surrendered her heart and let his circuits pour into her. At once, her consciousness was pulled into another world.
"Here…?"
Musashi staggered to her feet. Above her stretched a storm-covered sky. Beneath her, an endless wasteland. Thousands of swords stood upright like gravestones.
The Sword Graveyard. The tomb where every concept of the sword since its birth lay buried.
"Not memories… then this must be… my Master's inner world."
Something pulled her eastward. The wind rose, lashing her with storm-borne blades. She pressed forward anyway, impaled again and again.
Finally, she saw it: a colossal sword descending from the sky, pinning the earth itself. Its shadow blanketed a mountain of countless blades.
There was no path. To climb, she would step only on sharpened steel.
She did not hesitate. A blade pierced her foot as she began her ascent.
To master the sword — to reach emptiness — one must discard everything. No fear, no joy, no bloodlust.
Empty of all things.
At last, battered and torn, Musashi reached the summit.
There, upon a throne forged of blades, sat Shirou Muramasa — the sovereign of this mental world, the embodiment of Infinity itself.
This was the trial.
Only by defeating him could she claim his circuits and avoid annihilation from the sword-essence they carried.
And Shirou waited calmly, prepared. Even if Musashi had not reached the void before, here — in this world of no retreat — she would have no choice but to break through.