Mirror World, Downtown Fuyuki City
The once-prosperous streets had become nothing more than a battlefield. Buildings lay in ruins. Cars, trees, road signs—even reinforced concrete skyscrapers—were all scarred, sliced apart by impossibly sharp blades.
This was no mere "gas explosion."
Swish!
A streak of emerald light carved through the skyline. A distant tower split cleanly in half, collapsing in a plume of dust. Out of that haze, a lithe figure sprang upward, landing gracefully atop a rooftop.
Berserker-class Miyamoto Musashi.Her breathing was calm. In one hand she held a short sword, in the other a long blade. Her form embodied the essence of Niten Ichi-ryū. Every ounce of her presence was concealed, unreadable, leaving no hint of her next strike.
"It's really fun."
Her beautiful face shone with joy, lips curling in an excited grin. She hadn't experienced such a thrilling fight in ages—and this was her first true battle since ascending to the realm of [Space].
Her opponents: the sword familiars crafted by her own Master, Shirou Muramasa. Woven from torrents of prana, layered with the sword-principle of the [Lightning Pill], each one was an autonomous killing blade—an enemy that defended and countered on its own.
Only by clashing with them firsthand could Musashi grasp just how terrifying they were.
A sword servant had no body. No mind. No hesitation. Only the sword. Its technique was singular, stripped of all waste, elevated to the domain of [One].
The so-called "One": the blade that guarantees victory. From infinite angles, timings, and strengths, it selects the sole path to win.
Because it was not bound to a body, Musashi could not read its movements. Even with her Sky Eye, facing such a foe without reaching the realm of [Void] meant only one thing: a one-sided beating.
And yet, standing in the [Void], Musashi danced with two of them at once. Proof that each sword servant was easily a match for a first-rate Heroic Spirit.
The cost was steep. At present, Shirou's seal could sustain only three simultaneously. More would drain even Musashi's supply of prana. But in time—once Shirou's circuits refined—more could be summoned. Many more.
The battlefield burned green. Turquoise blades rained like arrows, each one seeking Musashi's life.
If [One] was the sword of certainty, then [Void] was the sword beyond certainty. To reject the rules of the world itself. To find life within death, victory within defeat. Where infinite possibilities meant nothing, Void was the blade that cut them all away.
It was like chess. [One] was the supercomputer grandmaster, perfect and unbeatable—save for a few rare prodigies. But [Void]? That was the man who ignored the rules entirely, moving a pawn to capture the king on the first turn. Even the strongest AI could only despair.
Steel flashed. Musashi's slender form wove between strikes, turning the ruined city into her dance floor. Hair whipping, sleeves fluttering—her style was as beautiful as it was deadly, like a flower dancing through heaven.
But two sword servants together were not "one plus one." Their combined domain was a cage of blades, coordinated to slay even peers of Musashi's caliber. Her Void could only delay the inevitable.
Above the battlefield, Doraemon hovered with his bamboo-copter, staring down at the wreckage with a relieved sigh."Good thing this is the Mirror World. If the real city got wrecked, we'd be in so much trouble."
Beside him, Shirou stood on a massive conjured blade, riding it like a surfboard through the air. One of his childhood dreams—flying on a sword—realized through Unlimited Blade Works.
He muttered, "The Church is going to have a fit. They'll probably rewrite the Grail War rules overnight. At this rate, we're headed straight into the Fate/Grand Carnival timeline."
After creating Unlimited Blade Works, Shirou had wasted no time beginning his "revenge plan." His victim: Miyamoto Musashi, used as a living whetstone to test his newly forged domain—all because she had once forced him into women's clothing.
Musashi, naturally, had been delighted to accept. Until the Grail War began, opponents of her caliber were rare. And besides, if a host requested it, what kind of guest could refuse?
Three days, ten matches later, Shirou had mastered every function of his Reality Marble.
Now, Musashi stood at the peak of the [Void], a Sword Saint in all but name. Against her, the sword servants pulled no punches. Every swing was one that could kill.
And Musashi wouldn't have it any other way. Swordsmanship, after all, was the way of life and death. A blade that never killed was a blade that never grew sharper.
From above, Doraemon's curiosity peaked."Hey, Shirou… if the Grail War is all about fighting for the Grail, does that mean you want it too?"
"The Holy Grail is every magus's dream." Shirou's answer was blunt. He didn't dismiss it just because Doraemon existed. To him, the Grail was nothing less than a colossal wishing machine.
He recalled Doraemon's [Double Potion]—the tool that ignored conservation of matter, duplicating anything infinitely.
1 becomes 2.2 becomes 4.4 becomes 8…
What if that potion were used on the Grail itself?
Doraemon blinked. "So the Holy Grail's really a universal wish-granting machine? Like, it really works?"
"It works." Shirou replied.
"Then… where's my wish-granting gadgets? They should be in here somewhere…" Doraemon dove into his pocket, fishing around frantically.
Shirou ignored him, circuits flaring."Draw the sword."
The seal blazed. Sword energy surged into Unlimited Blade Works. Consciousness linked to a sword servant, Shirou endowed it with the realm of [Infinity].
With Infinity's blessing, the familiar locked off all of Musashi's retreat paths, coordinating with its twin to close in from both sides.
"Perfect timing." Musashi's eyes narrowed. She felt the change instantly. Gripping both blades, she met them head-on. Her stance shifted—Zero Sword. A strike aimed to sever the link between Shirou and his creation.
"Not a chance."
Shirou's seal flared bright green. Infinity itself interposed, neutralizing Void. The Zero Sword's power faltered, striking the conjured blade without breaking its tether.
With Shirou in the mix, the tide turned. [Void] and [Infinity] collided, canceling each other out. The twin sword servants pressed in, their coordination flawless, and even Musashi—Sword Saint that she was—found herself pushed back, step by step.