This Is My Holy Grail War

In the blink of an eye, three days of the Holy Grail War had passed. Yet, not a single Servant had returned to the Throne of Heroes.

Despite its fierce potential, the battlefield had yet to descend into true chaos. Noble Phantasms remained sheathed, hidden away like treasures no hero was willing to reveal lightly.

It wasn't fear of exposing their True Names or a concern over mana.

The Noble Phantasm was the essence of a hero's legend, their ultimate glory. A crystallization of their lifetime's deeds, celebrated and immortalized. Who would casually unveil such an honor without encountering a worthy opponent to bear witness?

Now, one Servant had broken this tense stalemate. Caster—a "devil in human form," whose stories could frighten children into silence—had emerged from the shadows.

No longer content with mere slaughter in secrecy, Caster was driven by a twisted pursuit of "art," crafting grotesque masterpieces he intended to present to the one he held dearest: the "Holy Maiden of France" as he believed her to be—Jeanne d'Arc.

Caster's actions had enraged Fuyuki's overseer, Tohsaka Tokiomi. At the behest of his ally Kotomine Kirei, Assassin had been dispatched.

With Lancer's Master's identity exposed, a simple process of elimination left Caster to face the full wrath of Tohsaka and the Church. Kirei had already tasked Assassin with locating Caster's hideout…

Assassin had recently parted ways with Lancer, her slender silhouette fading into the shadows of the night. Just as she was about to fully dissipate into her spirit form, Lancer's voice stopped her.

"Assassin!"

At his call, Assassin froze mid-step. Reflexively, she materialized back into her physical form, wary of Lancer's intentions. Within moments, she activated [Not For One's Own Glory], taking on the familiar guise of Saber.

To Lancer, however, it seemed as though she had merely reappeared as herself.

Her iconic ahoge bobbed slightly as she tilted her head in confusion. "What is it you want?" she asked, her guard up.

"Your Master accepted a commission from Fuyuki's overseers, didn't he?" Lancer asked directly, his tone steady.

"That's correct," Assassin replied with a nod. Though commission wasn't quite the right word—her Master was the overseer himself.

"Then, by my Master's orders, I am to aid you in apprehending the vile Caster," Lancer declared with pride. "My noble Master has granted me leave to assist you, Assassin!"

His enthusiasm was palpable. To Lancer, this collaboration was not merely duty but a source of genuine joy. He held Assassin in high regard, recognizing her as a kindred spirit of valor and skill.

'Assassin, accept Lancer's aid. Also, find an opportunity to probe the secrets of his Noble Phantasms.'

Kotomine Kirei's voice resounded in Assassin's mind, cold and commanding.

Assassin's ahoge drooped in irritation. She muttered inwardly, Looks like I can't slack off anymore…

"Very well," she said aloud, her voice betraying a hint of reluctance. "Let's search for Caster together."

The night air felt colder now, or perhaps it was just the unwelcome company. Assassin found herself disliking this situation even more with each passing second.

The presence of another Servant at her side should have been reassuring, but for Assassin, it was anything but. Here in this foreign city, she had no allies she could trust, no comforts to soothe her heart.

I'd rather be alone.

"Assassin, how long have you been investigating this matter?" Lancer inquired as they walked.

"All day," she replied curtly.

"Then you must have found some clues," he said, his tone eager.

Though Assassin had only been in Fuyuki for a short time, she had already mapped much of the city in her mind. In truth, she had known Caster's hideout from the start. The actions of every Servant were no secret to her.

"Yes…" Assassin admitted after a pause. "There's an unusual concentration of mana in the waters of the Mion River." She refrained from directly naming Caster's lair, not wanting to reveal her full hand, especially with Kirei watching her every move.

"You're attuned to magecraft as well?" Lancer seemed genuinely surprised.

"No, it's simply too obvious," she said plainly. To her, Caster's presence had always been an open secret.

"Your talents extend beyond swordplay, it seems. Even the mysteries of magecraft bow to you!" Lancer praised her, then pressed further. "Can you deduce Caster's exact location from that clue?"

"Most likely, it's the sewers," Assassin speculated, offering a plausible guess. "But before I could investigate further, I encountered you."

"So fate brought us together," Lancer said with a grin. "Two warriors with different missions, crossing paths at just the right moment—it must be destiny!"

"Let us go, then!" Lancer's eagerness was contagious, and Assassin found herself leading the way despite her reluctance.

The sewers of Fuyuki were not difficult to locate. Assassin had already taken note of them during her daytime wanderings.

This path stinks—literally and figuratively.

The fetid stench of the underground passage assaulted her senses. Even with her enhanced body, the nauseating odor made her stomach churn. Yet, despite every fiber of her being urging her to turn back, she pressed on.

As they ventured deeper into the labyrinthine corridors, the oppressive darkness gave way to an even more pungent smell—a sickly, metallic tang that Assassin recognized immediately.

Blood.

"We're getting close," Lancer said grimly, his gaze fixed ahead.

The two advanced cautiously, their steps echoing against the damp walls. As they rounded a corner, they came upon a sight that made them stop dead in their tracks.

Blood, stench, sludge, and bone—scarlet filled their vision entirely.

Upon closer inspection, a disturbing pattern emerged from the disarray of corpses.

Each body bore signs of modification prior to its destruction, as if they were used to create something—yet every one of these macabre "creations" had been intentionally ruined afterward. The marks of deliberate vandalism were clear, suggesting dissatisfaction with the results.

It was like a potter smashing a carefully crafted vase in frustration. Only here, the medium wasn't clay but human flesh.

Both Ryūnosuke and Caster were in pursuit of what they considered the ultimate masterpiece. These mangled remains were mere failed experiments, discarded in their unrelenting quest for perfection.

Caster had annihilated these unsatisfactory creations one by one, fueling an unending cycle of death. This was why Fuyuki's missing person reports had skyrocketed in recent days.

The frenzied Master and Servant duo, consumed by a twisted passion, labored tirelessly to realize their ultimate "art"—a work worthy of the sanctified figure in Caster's delusions.

"Ugh…"

The nauseating scene proved too much for Assassin. Her body shifted into a shadowy blur as she dissolved into her spirit form.

Even with prior knowledge of Caster's atrocities, this grotesque spectacle was more than she could bear. She needed a moment to compose herself, or risk vomiting right there in front of Lancer.

It took several long breaths before she reappeared, regaining her composure, though her pale face betrayed her lingering disgust.

"Monsters! Abominations!" Lancer roared, his voice trembling with righteous fury. "I swear on my Master's name, I will see Caster brought to justice! No matter what it takes!"

But before he could act, a voice echoed through the blood-drenched corridor.

"Who dares intrude upon this sacred hall of art?!"

Caster's cry was as frenzied as his creations, equal parts rage and madness. His voice reverberated off the walls, sending chills through the air.

"This is the sanctuary of my dreams…" His tone shifted abruptly, softening as his manic eyes locked onto Assassin.

"Ah! Jeanne!"

Caster collapsed to his knees, tears streaming down his face. "No… I cannot face you yet, not like this… My work is incomplete… It isn't worthy! It isn't enough!"

His hands gestured wildly as if clawing at the air, his words veering between sobs and hysterical proclamations.

"My most pure and noble Saint… Is it truly you?"

Assassin's response never came.

Before she could speak, Lancer darted forward like a streak of crimson light, his spear raised to strike down the deranged Servant.

"Die, fiend!"

But before Lancer's spear could reach him, writhing black tendrils erupted from Caster's shadow.

With a sickening squelch, an unholy creature emerged—a mass of grotesque tentacles and malformed limbs, a sea demon birthed from Caster's accursed book, [Prelati's Spellbook].

However, such a beast was no match for a Servant. Lancer's spear slashed through it with ease, splitting the creature in two.

Yet for every one destroyed, more sea demons emerged.

Caster clutched his spellbook tightly, channeling mana into his summons.

"Jeanne, do you see this?! Your loyal servant is besieged by these blasphemers!" Caster wailed, his voice rising to a fever pitch. "They will not stop until they defile you as they have defiled the world! Am I to stand by and let this happen?!"

The air around Caster seemed to grow heavier as his magic intensified. With every moment, the cramped sewer filled with more and more grotesque creatures.

"I will not let them harm you!" he screamed, tears streaming down his face as he pointed accusingly at Lancer.

"You lapdogs of the divine, haven't you taken enough from her already?! She gave her life to you, and now you seek to rob her of her mind as well?!"

The sea of demons surged forward, an unstoppable tide of abominations closing in on Lancer.

'Do not interfere,' came Kirei's cold command in Assassin's mind. 'Stay back and observe. Let them reveal their Noble Phantasms.'

Kirei's voice was devoid of concern, focused only on strategy. He sought to exploit the situation, collecting intelligence while minimizing risk.

But before Assassin could decide her next move, the sound of a wall crumbling interrupted her thoughts.

A powerful presence surged into the room, radiating an overwhelming sense of justice.

It was Saber.

"All evils of the world shall be judged."

Saber stepped through the shattered wall, her regal presence an unyielding beacon amid the carnage.

Why is she here?

Assassin's mind raced. She hadn't sensed Saber approaching, yet here she was, her pristine armor gleaming against the crimson-stained backdrop.

Saber's arrival was no coincidence. Guided by Kiritsugu's orders, she had followed the trail of violence and madness to this unholy place.