[FATE] OP Demon King Across Multiverse!

Ryuu's words didn't elicit much of a reaction from Lev Lainur Flauros. Instead, the man merely smirked and said,

"Oh? So in another timeline, I haven't brought that world to ruin yet? That speaks of why you're still alive."

After speaking, Lev's gaze shifted toward Ritsuka and the others—though it quickly became clear that he was actually addressing Dr. Roman through the communicator.

"Are you listening, Roman? Since we're both magi who studied together, let me offer you one final piece of wisdom—

"The future has not vanished. It has simply been reduced to ashes."

A chilling realization settled over the group.

"So that's why we couldn't establish contact with the outside world," Ritsuka muttered. "It wasn't a communication failure—the people we were trying to reach no longer existed."

Mash's face paled as the full weight of their situation sank in.

Human history had been burned away.

Aside from Chaldea, everyone was gone.

Before anyone could fully process the horror of it, the ground shook violently.

Cracks spread across the floor. The entire cavern began collapsing as massive chunks of debris rained down from above.

Mash instinctively raised her shield, throwing up a barrier to shield Ritsuka and Olga Marie as they scrambled toward safer ground.

Meanwhile, Lev glanced at the chaos with amusement.

"This Singularity has reached its limit. Well then—farewell, Romani, Mash, Forty-Eighth Master… and Ryuu. I do hope we meet again soon."

With a dramatic flourish, Lev levitated into the air, spreading his arms as his form faded into the void.

Boulders crashed down from the ceiling. Even Ryuu had to move swiftly, dodging the falling debris.

"The underground structure is caving in!" Roman's voice crackled over the communicator. "Worse than that—the entire space is collapsing!"

"Doctor, initiate Rayshift—now!" Mash shouted.

"But what about the Director?! And Mr. Ryuu?!"

Olga Marie clenched her fists. She had already made up her mind.

She turned toward Ritsuka, her voice resolute.

"You go. Take Ryuu and Saber back with you."

"What? No! Director, you have to come with us!"

"There's no time! I'm already dead—going back won't change that."

"But—"

A massive boulder plummeted toward Ritsuka.

Mash barely managed to intercept it with her shield, sweat dripping down her forehead from exertion.

Seeing this, Ryuu made his decision.

"Olga's coming with you."

Everyone froze. Even Olga looked at him in shock.

"But you just heard him—I'm dead! How am I supposed to—?!"

Ryuu wasn't interested in arguing. Instead, he pulled something from his inventory—a lifeless body that looked exactly like Olga Marie.

"This is..." Olga's voice trembled as she stared at her own identical face.

"A Righteous Corpse," Ryuu explained. "A temporary body that allows dead spirits to move in the mortal world."

It was something he had exchanged from the system—a modified version of the body used by Death itself.

Without magic circuits, it wouldn't allow her to fight. But at least she wouldn't disappear.

Ryuu didn't wait for permission.

He forced Olga's soul into the corpse.

"AAGGHHH!! W-Wait! It hurts! What the hell are you doing to me?!"

"You'll thank me later. Doctor, execute the transfer!"

"U-Understood!"

The ground completely collapsed.

A blinding light enveloped Ritsuka, Mash, and Olga.

In the next instant—

They vanished.

Ryuu exhaled, watching as his companions disappeared into the Rayshift.

At last… it was over.

He turned toward Artoria, who had remained by his side the entire time.

"Alright, Saber," he muttered. "Let's go home too."

She nodded, and without hesitation, they activated the system's Return Summon.

A vortex of energy surrounded them—

And the world faded to black.

---

When Ryuu opened his eyes, he was greeted by the familiar sight of his throne room.

They had returned.

A wave of satisfaction washed over him.

Not only had he contracted Artoria as his first true follower, but his Demon King Points had skyrocketed to 7,700.

Not a bad haul.

He leaned back on his throne, casually opening his status screen.

"System, display my current power level."

— Host: Ryuu

— Power Rank: D+ (C)

The C-rank in parentheses indicated the boost he received from his followers.

Not strong enough to challenge the Hero just yet…

But that would change soon.

His gaze flickered toward the exchange shop.

The thing he had been waiting for was finally within reach.

"System—exchange for the Mangekyo Sharingan."

"Ding! Exchange successful. Please select two abilities from the following options:"

— Amaterasu

— Tsukuyomi

— Kamui

— Kotoamatsukami

— Izanagi

— Izanami

— Shinra Bansho

— Susanoo

Ryuu tapped his chin, deep in thought.

As much as Kotoamatsukami was tempting, he already had Geass.

For offense, he had enough firepower between Artoria's Excalibur Morgan and his own strength.

But in terms of survivability...

His greatest weakness was mental attacks.

The Hero's party had someone who could manipulate minds, and Ryuu had no defense against that.

Which meant his best option was…

"I choose Tsukuyomi and Kamui."

"Exchange complete!"

A sharp pain erupted in his eyes.

His vision burned as his black irises turned crimson, morphing into the iconic three-pronged shuriken pattern of the Mangekyo Sharingan.

The world shifted.

In an instant, he felt his connection to space itself.

He raised his hand—

And the space around his fingertips distorted, pulling inward like a vortex.

"Kamui... huh?"

A grin spread across his lips.

He was untouchable now.

With this, he could phase through attacks, transport himself into his personal dimension, and even warp others inside.

He had essentially gained an escape button.

Ryuu snapped his fingers—

And vanished.

---

Inside Kamui's Dimension

A swirling void stretched endlessly in all directions.

Nothing existed here—no time, no life, no escape unless he willed it.

Ryuu smirked.

"This could come in handy."

With another flicker, he reappeared back on his throne.

Artoria jumped in surprise.

"Master—what just happened?"

"Relax," he chuckled. "Just testing out my new power."

Her eyes narrowed slightly.

"...I see. You continue to grow stronger."

"Of course."

He leaned forward, resting his chin on his fist.

"I'm not stopping here, Saber. This is just the beginning."

For now, his battle with Chaldea was over.

But the war against the Heroes of his own world…

That was another story.

And he was going to win.

No matter what it took.

======

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