IBHJ 1400

Her smile thinned. “His own Servant turned against him. And killed him.”

Artoria’s eyes narrowed. “…But you said their universe had no mystery. How could they summon Heroic Spirits?”

“At the end of science,” the woman said, “you always find something that looks a lot like mystery.”

Artoria said nothing.

“The Fool died. His Servant took control of the Golden Universe. With the fake First Cause in hand, he carved out a space to survive—a sealed-off realm clinging to the shell of your universe.”

“Golden Universe still collapsed. The Void Overlord kept eating it. But life could keep going, inside that stolen pocket. In that sense… their world kept living by piggybacking on half of yours.”

“The two universes, once meant to replace each other, ended up coexisting. Like overlapping reflections.”

She glanced down at her cup, now empty. “But then someone stole the core of that realm. And that core…”

“…was the fake First Cause,” Artoria finished.

The woman nodded. “Also called the Vortex. A door that leads to the real First Cause. Once it was taken and brought here, the seal broke. That pocket realm began to fall apart. The Void came back.”

“To rerun the First Cause War, the thief used the Vortex to create a pawn. But the plan collapsed. Ideological war broke out. The planets, led by Origin Gaia, rebelled. They killed the thief. And what came after—the war with the Lord of Salvation—you already know.”

“In the end, Origin Gaia was dying. With what strength she had left, she used the stolen Vortex as a blueprint… and made another one.”

“That second Vortex is here. And right now, it’s inside Shirou.” She met Artoria’s eyes. “It’s our Universe’s Gate.”

Artoria finally understood.

This wasn’t just a Grail War. It was a war between two universes—a First Cause War.

In the distant past, the Golden Universe had forged the first Vortex and used it to link themselves to the First Cause. They survived by anchoring their last fragment to this universe.

Then came the Age of Origins.

The Origin Civilization rose and wiped them out. But that victory brought its own war—one fought against the Lord of Salvation. And in its final breath, the Origin Civilization created a second Vortex. A gate of its own.

The first Vortex—born from the Golden Universe—now lived inside Manaka Sajyou.

The second, forged by Origin Gaia, had been passed to Fujimaru Shirou.

“…Then what about the Lord of Salvation?” Artoria asked.

“He was the Fool,” the woman said. “The one who won the Cosmic Grail War. After his Servant betrayed him and ended his life, his soul slipped through the Gate. It reached the real First Cause.”

Her eyes met Artoria’s.

“His will stained it. And I—”

She placed a hand over her chest.

“I was created by Origin Gaia, shaped from the second Vortex during the forging of the Arrow of Akasha. I’m a fragment of the First Cause.”

Artoria’s hands curled into fists. “Then why the hell didn’t you say that from the start?! Are you trying to help him?!”

The woman looked down. Silent.

Mana stepped forward, slipping between them.

“Stop. She didn’t know all this at first either,” she said. “She learned it the same way we did—piece by piece. It’s how she was made.”

Artoria didn’t look at Mana. Her gaze stayed locked on the woman. “Then tell me how to beat him.”

The woman’s voice came quiet.

“I don’t know.”

She lifted her head.

“I’m just a vessel tied to the First Cause. I feel things—I don’t understand them. But this much I can say…”

She paused.

“That thing—the Lord of Salvation—has never lost. Even Origin Gaia only understood what he truly was… at the very end.”

…

…

“I didn’t expect this,” Shirou muttered.

Origin Gaia had seen the signs—every fragment, every contradiction. Together, they led to one conclusion:

This was a Holy Grail War spanning two universes.

And the prize wasn’t just a wish. It was the First Cause.

Then that so-called Golden Destroyer—

“…must be the Cosmic Spirit who betrayed the Fool,” Origin Gaia said. “That’s why the war between our universes was inevitable.”

That’s when Alaya spoke.

[INTRUSION—INTRUSION. MASSIVE HOSTILE SIGNATURES DETECTED.]

[UNABLE TO REPULSE—UNABLE TO REPULSE.]

A projection flared to life—real-time footage of the stellar edge.

Shirou turned to it. And saw.

An endless fleet of golden astral barges, gliding in from the rim of existence.

“The Golden Universe has begun its invasion,” Origin Gaia said. Her hands closed tight.

The first Vortex—bound to the First Cause—had been their anchor, their last foothold. But it had been taken during the Gaia siblings experiment. Moved here. To this domain.

Of course they’d come for it.

…

Before the strongest being born beneath the First Cause, even Alaya was outmatched.

Origin Gaia felt it the moment he arrived.

The Golden Destroyer—his name had long since passed into legend. But standing against him now, she understood why he terrified even the Void Overlords. This was the one who’d defied extinction itself.

Alaya clashed with him in open space. Her attacks warped systems, tearing through void and matter alike. But when she realized he could kill her, she broke off and fell back hundreds of light-years, shifting to long-range tactics and bombarding him from afar.

The Destroyer didn’t chase her.

With a glance, he assumed control of a colossal Void Worm and turned it toward the Solar System.

Shirou’s chest tightened. He didn't hesitate. In the next moment, his body surged with light—his body shifting into that of his Emperor form.

Origin Gaia moved just as fast. She anchored herself to the Earth’s stellar output, siphoning quantum from every corner of the system. It gathered in her hands—folding itself into a cosmic weapon.

The Blade of Starfield.

She wasn’t alone.

Venus stepped forward, her own star-forged weapon in hand. Saturn followed. Then Mars. They each drew power from their planetary cores.

These weren’t Counter Force shadows or leftover UOs. These were the true planetary spirits. Living Wills. What humanity called Ultimate Ones were only fragments—reflexes and instincts turned to static echoes.

But now the Origin Lifeforms had returned.

One by one, they took form—light condensing into bodies, limbs, blades. A formation of celestial sentinels, rising across the void. The Solar System itself had taken up arms.

“This takes me back,” Gaia murmured, lowering her head with the hint of a smile.

She remembered it clearly—the rebellion she and her siblings sparked during the Golden experiments. When they turned against the Golden Giants and slaughtered them to the last.

“A fine memory, wouldn’t you say, Venus?” she said lightly.

“Shut up,” Venus snapped.

Gaia laughed.

Then she turned to Shirou.

“Hey. You’re not fighting here, are you? This isn’t your battlefield.”

A pause.

“Save your strength. For the Lord of Salvation.”

Shirou met her gaze.

“I know.”