Aozaki Aoko Case File

Credits: Nitorxs

Once the general goal and plan were established, Aoko and Touko decided to head to Fuyuki City as soon as possible. The two sisters explained the situation to Alice, who listened silently for a moment before sharing her thoughts.

"If you're fine with your combat strength, then I won't be coming along," Alice said calmly, sipping her tea.

"?!"

Aoko looked puzzled.

"Why?"

"...Because of the leyline in Misaki Town, you idiot," Alice shot Aoko a reproachful glance.

"The leyline and sacred land here require at least one of us to stay behind and guard it, or someone will come and try to seize it."

"Ah, that's a problem," Aoko admitted, suddenly understanding. "Though I don't often need the leyline, I guess it's pretty important for a magus family…"

"You just rely on being a Magician and don't worry about such things," Touko sighed from the side.

"If a magus family loses its leyline environment for too long, their magic circuits will degrade over time. Eventually, they might even disappear, turning into ordinary people."

"Is that so?"

Aoko shrugged, unconcerned.

"I didn't know about that… Or maybe I just didn't care? I always thought controlling the leyline was just about managing magical resources."

"Listen carefully," Touko raised a finger, her tone turning serious.

"All leylines and sacred grounds are gifts of the world that can only form naturally. For magus, leylines and sacred grounds represent a river connecting the inner and outer sides of the world."

"...After the Age of Gods, most mysteries returned to the 'Inner Sea of Stars,' deep within the planet," she continued.

"But since some mysteries remain on the surface, it means the separation and return were not complete. The great source of magic still leaks from the Inner Sea of Stars, and these leaking paths are called leylines."

"Hmm, so the leyline might be the biggest reason why magus still have magic circuits—this mysterious organ?"

Aoko murmured.

"No wonder Makiri Zolgen's descendants keep getting weaker—the leyline in Fuyuki doesn't match his origin."

"Very likely," Touko nodded.

"I've seen his information in the Einzbern records. He was once friends with the famous alchemist Hoenheim. For someone like Makiri, falling to the point of relying on parasitic worms to extend the lives of his descendants… time wasn't his only enemy."

"That guy's soul and seals have rotted away," Alice added.

"If Tohsaka were still a man, the Matou family would've been wiped out by now. Although the old bug might not have died."

"You have a twisted sense of humor..."

Touko glanced at Aoko with a strange expression.

"Even most typical magus wouldn't tolerate that kind of manipulation."

"Respect your older sister, Touko-chan," Aoko teased, flicking Touko's forehead, causing her to yelp in protest.

"But you can't call me an idiot!"

"One day, I'll get back at you for this!"

Touko rubbed her forehead, stubborn tears welling up in her eyes. "Just you wait!"

...

Considering how weak the combat capabilities of Irisviel's duplicate were, Aoko and Touko decided to leave her behind at the Kuonji Manor after removing her Lesser Grail function.

Irisviel's duplicate had mixed feelings upon hearing that the Aozaki sisters were heading to Fuyuki City for the Holy Grail War. She knew that although she was essentially identical to the original Irisviel, she was not the original Irisviel herself, nor the mother of Illyasviel. However, she couldn't help but feel a lingering attachment to Kiritsugu Emiya and Illya. This attachment was buried deep within her, surfacing only in occasional moments when she gazed out the window, lost in thought.

This behavior was the result of nearly a year of teachings (and subtle manipulation) from Aoko and Touko. Over time, Irisviel had also come to like the cute little girl Caren, which helped ease some of the longing she felt for Illya.

To ensure their participation in the Holy Grail War didn't leak prematurely, Aoko repeatedly used teleportation magic to take Touko to the Einzbern Castle located on the southwestern outskirts of Fuyuki City. Before entering the castle, they cast invisibility spells to ensure their presence went undetected, no matter how alert their opponents might be.

Upon arriving at the Einzbern Castle, Touko shared her plan to purify the Greater Grail by transferring the Avenger's soul with Acht. After hearing the plan, Acht agreed there was no better solution and offered additional details to aid in handling the Greater Grail.

During this time, neither Kiritsugu Emiya nor anyone else was allowed to overhear. Touko personally sealed off the exchange of information with runic symbols to ensure absolute privacy.

According to the plan, Kiritsugu Emiya would act as the official master of the Einzbern family, while Aoko and Touko would enter the Holy Grail War as independent participants. This arrangement had been decided a year ago.

Acht's reasoning for this was twofold: he didn't want to waste the already-hired magus-killer, and he wanted to avoid putting all their eggs in one basket. Even if Aoko and Touko failed to purify the Greater Grail, sometimes you never know the outcome until you try. After all, the basic function of the Greater Grail hadn't changed—it would still open a portal to the outer world. And the Third Magic, designed for the salvation of humanity, was still the Third Magic, wasn't it?

Once the meeting concluded, Acht handed Avalon, the Holy Relic, to Aoko and Touko.

This top-tier treasure from the Type-Moon world was entirely golden, adorned with intricate blue patterns embedded in its surface. It bore no signs of human craftsmanship as if it had been born of nature itself. Even though Aoko wasn't its true owner, she could still feel the immense power of healing and protection emanating from the relic.

It was a power that surpassed even the Five Great Magics, connected to the eternal land of the Inner Sea of Stars. Yet, even Avalon—would eventually fade away when the great source of the planet was exhausted. Eternal was, in the end, more metaphorical than literal.

In this universe, the only true eternity was the origin of all things—the ultimate dream of magus, the whirlpool at the root of the world, beyond the outer realms.