This was an extraordinary space, filled with inexplicable mystery.
It was as if the space within had been stretched and twisted—though the walls surrounding it were clearly visible, determining how far away they were proved utterly impossible.
What should have been an ordinary room thus appeared incredibly vast.
It was undeniably a marvel.
On the ceiling above flowed water, suspended like a clear lake overhead.
Within this suspended lake, all manner of water lilies blossomed, accompanied by other, more exotic vegetation whose names defied description.
At the center of this surreal space floated an enormous altar.
Spherical and radiant like a small planet, it hovered gracefully, illuminating everything around it with a gentle glow.
Standing before this spherical altar were three figures.
One was Amakusa Shirou Tokisada.
One was Semiramis.
The last, displaying a look of perpetual excitement, was the Caster who had yet to appear in front of Jeanne.
"So this is the Greater Grail?"
Caster gazed up at the altar, floating like a celestial body, in awe. Unable to contain himself, he eagerly pulled out pen and paper to jot something down.
"Subarashii—!" he whispered breathlessly, eyes filled not with greed but with an incomprehensible fanaticism.
Having been hidden deep beneath Trifas, the Greater Grail had tirelessly absorbed magical energy day after day, year after year. Over sixty or seventy years, the amount of accumulated mana within it had become nothing short of terrifying.
It was, after all, powerful enough to summon Heroic Spirits into the world and grant the victor's wish.
Yet even considering that immense magical drain, the Grail still brimmed with seemingly boundless power. Summoning fifteen Servants, counting even Ruler, would normally consume an immense amount of mana—far beyond anything ordinary magic could sustain.
Yet, despite this tremendous expenditure, the Grail remained overwhelmingly full, as though it had spent but the tiniest fraction of its vast reservoir.
With mana so immense, the Grail could achieve feats utterly beyond human reach.
In some ways, calling it an omnipotent wishing machine wasn't unreasonable.
"Though it leaked a little mana during its extraction from the ley lines, the loss is insignificant, hardly enough to affect the Grail's capabilities," Amakusa Shirou Tokisada remarked calmly, wearing his usual serene smile as he regarded the Grail. These words were meant as reassurance—not just for his Servants but also himself.
"Time is now of the essence. We must swiftly proceed to the next stage of the plan."
Amakusa's gentle smile belied the fierce determination burning in his eyes—a blazing resolve that could scorch anyone who looked too closely.
Semiramis, standing nearby, cast an accusing glance toward Caster.
"If it weren't for you, Rider and Lancer might still belong to the Red Faction."
Caster responded with an awkward chuckle, offering no excuses. After all, what had been done was done—no explanations could undo it now.
"We must simply make the best use of the little time we have left," Amakusa calmly intervened, neither blaming nor excusing Caster further. He'd never expected much battle capability from him anyway; simply not being a hindrance was enough.
Even Amakusa Shirou Tokisada hadn't expected that Jack the Ripper's Master had another Assassin Servant.
Reflecting for a moment, he understood: the Grail naturally summoned another Servant to maintain balance, compensating for the additional Servant on the Black side.
He'd initially thought Arthur had been summoned by the Grail specifically to balance the overwhelming power of his faction, but clearly, this wasn't entirely the case.
More likely, that Assassin had infiltrated the Church much earlier—probably when Matou Zouken first visited the Holy Church.
Amakusa lacked the full authority of a Ruler, unlike Jeanne, and couldn't easily pierce Assassin's concealment to detect his presence.
His [Revelation] is not omniscient. Though he had sensed something was amiss, he hadn't discerned exactly what.
His attention had been overly focused on Jack the Ripper—Matou Zouken's Servant—and though he'd successfully defended against her attacks, he hadn't anticipated that another Assassin had sabotaged them from within.
Semiramis' [Hanging Gardens] possessed surveillance functions, yet this Assassin had remained close to the Masters, making it impossible to detect his infiltration.
By the time the Assassin had slain most of their Masters and usurped their Servants' contracts, the damage had already been done.
Only Caster, who happened to be present, had managed to protect his own Master.
That Assassin clearly knew the danger posed by the [Hanging Gardens]. When confronted by Caster, he had immediately retreated without hesitation, abandoning the kill and swiftly escaping.
Semiramis had been occupied battling [Adam, the Primordial Human]; by the time she noticed Assassin, it was already too late to stop his escape.
"Hassan-i Sabbah, the one of the Cursed Arm, was it?"
Based on Caster's description, Amakusa swiftly determined the Assassin's identity.
It wasn't due to [True Name Discernment]. In this world, various subcategory Holy Grail Wars had occurred repeatedly, summoning nearly every Hassan at some point.
All had been documented by the Mage's Association, and Amakusa had meticulously reviewed these records.
He knew the appearance of each Hassan intimately. Even without resorting to [True Name Discernment], identifying the Assassin was straightforward enough.
"Once I begin my task, I won't be able to command you directly anymore. Have you finished your preparations?" Amakusa asked, turning toward Semiramis after glancing at the Grail.
"My Master, just who do you think you're speaking to?"
Semiramis smiled dangerously, her face openly displaying displeasure.
"I am the Empress of Assyria. Commanding armies in battle is certainly something I excel at—far more so than a boy who once merely led a paltry thirty thousand men."
Although the Red Faction had suffered heavy losses, the Black side had similarly fared poorly. Currently, Amakusa's true enemies were the viper-like Matou Zouken lurking in darkness, and Jeanne—the Ruler of this Holy Grail War.
Neither Amakusa nor Semiramis had any real regard for the Black side's remaining Servant—Astolfo. After all, his battlefield contribution had been negligible at best.
Even if Astolfo hadn't left to deliver the homunculus back then, his involvement in any of the fights—whether between Karna and Vlad III, Chiron and Achilles, or Adam against the [Hanging Gardens]—would have been utterly pointless.