IBHJ 1348

If the Cosmic Alaya’s quantum assault was like true damage, aimed straight and clean—

Then the Golden Emperor was the kind of unit you couldn’t even click on in the first place. Untargetable. Invincible.

Shirou pulled out the [Arrow of Akasha] and turned to Tethys. “Even this isn’t enough to kill the Golden Emperor?”

“Of course no—” She stopped mid-sentence.

Her eyes locked onto the Arrow. She didn’t blink.

“…What is that?” she asked quietly.

“The Arrow of Akasha,” he said.

“Incredible… I didn’t think anything like this actually existed…” she murmured, still staring at it. Then she turned to him. “May I examine it? Just for a moment.”

“Go ahead. It was yours to begin with,” he said without hesitation, handing it over.

Tethys took it with both hands, careful and reverent without even meaning to be. Her gaze traced the form of it, completely absorbed.

“…This structure… it’s nothing I’ve ever seen before. It’s not made of information. Not law. Not matter. It’s something else entirely… like the pure shape of the source itself.”

She looked up again, meeting his eyes. “If it’s this Arrow—then yes. It could kill the Golden Emperor. But only once.”

He froze. “Just once?”

She nodded. “Originally, the Arrow of Akasha could be used three times. But two charges have already been spent. Only one strike remains. You didn’t know that?”

Shirou frowned. This was news to him.

It had been spent twice already. Once in pan-human history—when the Origin Lifeform sealed the Lord of Salvation. And again, when he’d used it to erase Sixth Seat.

Which meant this next one would be the last.

She held the Arrow for another quiet moment, then gently handed it back. “Take good care of it, Shirou.”

He accepted it with a slow nod. “If this thing can actually kill the Golden Emperor… shouldn’t you be the one to use it?”

She shook her head. “You came to this era for a reason. That’s why the Arrow ended up here. I have a feeling it’s meant for something even more important than the Emperor.”

Her smile was soft. “Besides, he’s our old rival. As the elder here, I’d feel shameless relying on the younger generation’s power.”

Then, without warning, she leaned over from her perch on his shoulder and patted his head.

“And watch your manners. It’s Grandma Tethys.”

Shirou sighed. There was no winning with her.

“Oh right! Come with me to the Moon, Shirou!”

Before he could ask what she meant, a white hole blinked open beneath his feet.

He yelped, completely caught off guard—

—and the next thing he knew, he was standing on the Moon.

Shirou took one look at the cratered terrain around him, then glanced up at the silhouette of the Earth-Moon Observation Post in the distance. He turned to glare at her. “How many times do I have to say this? Stop teleporting me without warning.”

“Oops. Forgot.” Tethys smiled brightly. “We’ll talk about it next time.”

Before he could reply, a streak of light cut across the sky.

Shirou looked up and saw massive starships rising from the Observatory, burning toward the edge of the Gaia Sector.

So Gaia had made her move.

Those ancient warships—built during the material era and left dormant ever since—had finally been summoned to the front.

Maybe… Tiamat was among them.

Shirou lowered his gaze. “What are we doing here?”

“To grab the Golden Universe’s coordinates, obviously!” Tethys said, like it was the most natural thing in the world. Then she tilted her head. “Huh? Why do you look like you hate being on the Moon?”

He sighed inwardly. It was fine now…

But one day, the Moon was going to be a serious problem.

“Over here, Tethys! Over here—!”

A bright voice called out nearby. Shirou turned to see the young Moon-chan waving at them with both hands, smiling wide.

He and Tethys started walking in her direction.

After a brief round of greetings, Moon-chan turned and led them into the heart of the Moon.

Deep beneath the surface, buried in the lunar core, waited a colossal photonic crystal. It pulsed with dazzling light, casting shifting reflections across the chamber walls. This was no ordinary structure—it had long since replaced the Moon’s original core.

And it was none other than the Mooncell.

The very same entity that, in the far future, would drive Crimson Moon to madness.

Back in the age of material life, the Origin Civilization had managed to repel the Golden Universe’s incursion. But even then, they’d never uncovered its exact coordinates, much less its internal structure.

But now—now Mooncell was here.

And everything changed.

After all, the Golden Universe’s roots ran through Mooncell. In a way, it was part of their legacy.

If not for the civil war between the Golden Universe’s stationed observers—an internal collapse that led to their own destruction—even Gaia and her siblings might have been dissected, reduced to test samples, and treated as nothing more than raw data.

Mooncell held what Gaia needed most: information. Real, structural knowledge about the Golden Universe.

And this wasn’t the compact machine of the far future. It was massive—far larger than the Mooncell Shirou had seen before. The glowing crystal filled the Moon’s hollowed-out core, flooding it with refracted brilliance.

“Mmm.” Tethys floated slowly around the structure, making a few slow loops as if gauging its size. Then she turned to Moon-chan.

“Think we can move it?”

“Sure ya can!” Moon-chan beamed. “If it helps Gaia, take whatever you need. Just leave a chunk behind—it’s still hooked up to my core.”

“That’s why I called Shirou over,” Tethys said, smiling as she turned toward him.

He looked around the chamber. “Isn’t this observatory a relic from the Golden Universe? What makes you think I can even cut into the Mooncell?”

“I saw you fight Uranus,” she said, blinking like it was obvious. “You’ve got the power to slice through the origin of law and matter, right?”

Shirou let out a long sigh. “You know, I should really start charging for this kind of labor…”

He closed his eyes, tapping into Shiki’s records. When he opened them again, the world had changed.

Death lines shimmered across the surface of the Mooncell.

He stepped forward, locked onto the link between the photonic crystal and the Moon’s core—and drew a single clean cut.

Shhhk!

Before Moon-chan’s astonished eyes, the crystal—untouched even by Gaia—split apart without resistance.

“Th-that was amazing…!” she gasped, eyes wide with awe. “Gaia couldn’t even scratch it, and you just—wow!”

Her sparkling blue irises locked onto Shirou like he was some kind of myth.

He calmly sheathed his Caliburn and turned to Tethys. “That’s my part done, right?”

“Yep,” she replied with a grin. “Now it’s my turn. I’ll transfer the crystal and let the others tear through the data. No more wandering around blind.”

He nodded. With his help, the Origin Beings were preparing to strike during the Golden Universe’s moment of internal chaos. But before they could move, they had to understand what they were up against.

This was the first step.