Aozaki Aoko Case File

Credits: Lumn

"Kiritsugu," said Irisviel as she walked in from another room of the Einzbern castle in Fuyuki. She sat down beside her husband.

"Acht says all the materials have been delivered to Fuyuki."

"...Good," Kiritsugu Emiya replied, momentarily pulling his mind away from his deep thoughts to acknowledge his wife.

"Let's go meet with Assassin. There are still some things I need to confirm with her."

Irisviel nodded and followed him closely as they made their way to the castle's Throne Room.

When Kiritsugu pushed open the doors, they were met with the sight of a strikingly beautiful woman with flowing black hair, dressed in an elegant black-and-gold gown. Her pointed, elf-like ears gave her an otherworldly presence.

At that moment, Assassin was inspecting several objects inside a box. A closer look revealed the contents to be fragments of weathered earth and stone.

"Assassin, how are the preparations coming along?"

Kiritsugu asked.

Assassin carefully placed the stones back into the box, then channeled a small burst of magical energy through her hands, disintegrating the dust and soil clinging to them.

"Even I'm a bit surprised. That family behind you managed to transport such a large quantity of materials to this distant land so quickly."

"...Acht spent half of the Einzbern family's fortune to make it happen," Kiritsugu replied, his voice devoid of emotion.

"It took nearly a year to move those materials from the Middle East to Fuyuki City."

"Impressive," Assassin remarked, her eyes narrowing with interest.

"I hope your so-called Noble Phantasm is as powerful as you claim. From the intelligence I've gathered, your competition in this Holy Grail War won't be so easily overcome."

"Are you counting our allies among those competitors?"

Assassin asked, a faint grin tugging at her lips. She swirled a glass of crimson liquid that resembled blood and leaned back against the throne.

"I can already smell the stench of betrayal."

"We have no intention of betraying Miss Aozaki," Irisviel interjected, her voice firm.

"All these preparations — including the relic used to summon you — were arranged by Acht to ensure our victory in this Holy Grail War. Whether it's Kiritsugu or Miss Aozaki who claims the Grail, the Third Magic will be realized."

"Say whatever you like, homunculus girl," Assassin smirked. To her, withholding crucial information from an ally was no different from betrayal.

"I don't care if you betray your allies or not. If anything, I'm curious to see if you can succeed."

"Acht has adhered to the terms of the contract," Kiritsugu said, his tone unyielding.

"Your job is to fulfill your duties. Focus on that and leave the rest to us."

"Spare me the righteous facade," Assassin scoffed.

"I've seen too many of your type before. Just because Acht follows the letter of the contract doesn't mean you will. After all, you're the kind of man who'd sacrifice his wife without a second thought. What about you could be trusted?"

Kiritsugu's hand tensed into a fist, but he didn't argue. Assassin's words struck closer to the truth than he cared to admit.

"Kiritsugu..."

Irisviel took his hand in hers, her soft voice filled with compassion. "It's not your fault. I chose this path willingly. Everything we do is for Illya — so that she can live in a better world."

Hearing Irisviel's words, Assassin smirked with thinly veiled derision.

This homunculus girl doesn't understand the true nature of Kiritsugu Emiya, Assassin thought. She's still clinging to the noble lie that he's doing all of this for his daughter's sake. Pathetic.

Still, she couldn't deny her interest. Regardless of how this Holy Grail War ended, she wanted to see for herself what fate awaited this man obsessed with saving humanity.

"Have you prepared the item I requested?"

Kiritsugu asked, ignoring the mockery and Irisviel's attempts to console him. His voice was cold and pragmatic.

"Of course," Assassin replied, flicking her wrist. A small, ornate vial materialized in her palm. Its contents were a swirling, sinister green liquid that gave off an aura of corruption and poison.

"Unlike some people, I honor my agreements," she said with a smirk. "If I promise to do something, I do it."

Kiritsugu reached out, and the vial floated into his hand as if pulled by an invisible thread. He inspected it carefully, his eyes sharp with scrutiny, before tucking it into the inner pocket of his coat.

"...How much longer until your Noble Phantasm is ready?"

"If you're urgent, I'll need three days to conduct the ritual," Assassin replied nonchalantly.

"So? Are we doing this or not?"

"Wait for my signal," Kiritsugu instructed.

"Once the Holy Grail War reaches the appropriate stage, I'll let you know."

Assassin raised an eyebrow but gave no further argument. She waved them off like she was dismissing servants from her presence.

With nothing more to discuss, Kiritsugu turned and walked out of the Throne Room, Irisviel following close behind.

Once they were alone in the hallway, Kiritsugu headed toward the massive underground chamber beneath the Einzbern castle.

This vast space had been excavated as part of the larger operation Acht had initiated to transport materials from the Middle East. Countless homunculi had been expended to complete it in just one year.

The chamber was cavernous, lined with bricks, stones, and sand — all arranged in exact configurations according to Assassin's precise instructions.

Even the structure of the Einzbern castle itself had been integrated into this massive project, transforming it into a single cog in a much larger, hidden plan.

Acht and the Aozaki sisters had reached an agreement to conduct this joint effort, but the Einzberns kept the sisters deliberately uninformed about certain backup measures.

The reason was simple: Acht didn't trust anyone fully.

The Aozaki sisters had come close to achieving the materialization of the soul, a feat worthy of reverence, but trusting them completely? Unthinkable.

If the Aozaki sisters succeeded, then everything would go as planned. The Einzberns would achieve the Third Magic, and Acht would have no qualms handing over what little wealth remained to them.

But if the Aozakis failed, there would be a backup plan. This was that backup plan.

It was why Assassin had been summoned and why these materials had been transported halfway across the world.

Acht's plan was foolproof. Or so he believed.

But there was one flaw in his logic.

The Magus Killer named Kiritsugu Emiya had a plan of his own.

Kiritsugu's plan didn't align with the wishes of the Einzbern family or the ambitions of the Aozaki sisters.

He gazed at the small vial of Hydra venom in his hand. Its eerie green glow reflected in his eyes as he fell into silent contemplation.