[FATE] OP Demon King Across Multiverse!

Ryuu watched as Mash was occupied by Cú Chulainn, his golden eyes gleaming with a chilling intensity. The killing intent in his gaze was unmistakable.

Fujimaru Ritsuka felt her breath hitch as she instinctively stepped backward, her body trembling under the sheer pressure Ryuu exuded.

"Is that all the resolve you have?"

Ryuu's voice was eerily calm, each step forward causing the ground beneath his blade to screech in protest.

Ritsuka's back pressed against a cold, unyielding wall—there was nowhere left to retreat.

"Ryuu-senpai… why?"

"If you're this weak, you'll die sooner or later. It's better if I end it here quickly."

"No… no, Mash!"

The moment Ryuu swung his blade, the Command Spell on Ritsuka's hand flared, glowing an ominous crimson. In an instant, Mash leaped forward, her massive cross-shaped shield raised, intercepting the fatal strike.

The impact sent a shockwave through the air.

So, she activated the Command Spell unconsciously? As expected of the one chosen by fate, Ryuu thought to himself. The protagonist never dies so easily.

"If you're choosing to protect her, then so be it," Ryuu muttered before turning to Cú Chulainn. "Caster, use that technique!"

"Heh, you got it!"

Without needing to chant, Cú Chulainn traced glowing runes in the air, summoning a spiraling vortex of wind.

Mash's mind raced—she recognized this attack. A flame tornado—just like the one she had witnessed earlier.

Ryuu's body ignited in blazing crimson flames, his dragonic aura intensifying. The moment he raised his sword, the inferno twisted into the storm, transforming into a pillar of flame that shot into the sky.

Both Ryuu and Cú Chulainn swung their weapons, unleashing the firestorm directly toward Mash.

The scorching heat made the air waver. Mash clenched her shield tighter, gritted her teeth, and without hesitation, turned back toward Ritsuka.

"Senpai, stay behind me!"

"Mash, you—!"

The firestorm consumed both of them, swallowing them in an all-consuming blaze.

Silence followed.

Ryuu remained motionless, his golden pupils fixed on the inferno.

If they lacked the resolve to fight, then they deserved to perish. That was the unchanging rule of the battlefield.

Seconds stretched into eternity. Even Cú Chulainn began shifting uncomfortably—this was enough to kill a human.

Then, suddenly—

A brilliant white light burst forth from within the flames.

A barrier materialized, a towering fortress of radiant energy shielding Mash and Ritsuka from the inferno.

Mash's Noble Phantasm had awakened.

The fire dissipated, revealing the two figures standing within the protective barrier.

Ryuu's lips curled slightly as he exchanged glances with Cú Chulainn.

"Looks like she did it," he mused.

The massive citadel-like shield shimmered before fading, leaving Mash and Ritsuka collapsed on the ground, utterly drained.

"I… I did it, Senpai!" Mash whispered breathlessly.

Ritsuka rushed to her side, gripping her hand. "Mash, you were amazing!"

Ryuu stepped forward, his blade resting on his shoulder as he peered down at her. "Impressive. Your 'heart that protects' is finally strong enough to manifest."

With a smirk, he leaned down and scooped Mash into his arms.

"Since you're completely drained, I'll carry you for now," he said.

"Wha—?! No, please, put me down!" Mash stammered, her face glowing bright red.

But Ryuu simply ignored her protests, casually handing her shield over to Cú Chulainn.

Meanwhile, Ritsuka's hair was disheveled from the aftermath of the battle, but she was unharmed.

At that moment, Olga Marie finally regained consciousness, groggily rubbing her temples. Her gaze immediately locked onto Mash in Ryuu's arms, and her temper flared.

"You bastard—what did you do to Mash?!"

Ryuu sighed, rolling his eyes.

"I just helped them understand the reality of war," he replied nonchalantly. "And as you can see, Mash is now capable of using her Noble Phantasm."

"But there were other ways to accomplish this!" Olga snapped. "They didn't have to be thrown into battle like that!"

"One day, they would have to face this reality anyway," Ryuu countered. His voice was sharp, unwavering. "You can try to shield them all you want, but in the end, only the strong survive."

Ritsuka lowered her head, gripping the hem of her coat. She looked at Mash, lying weakly in Ryuu's arms, and her expression filled with guilt.

Ryuu, noticing this, stepped forward and spoke softly:

"You did well."

Ritsuka's eyes widened.

"If you had chosen to run away, I would've killed you without hesitation," Ryuu admitted.

"But I didn't do anything," Ritsuka muttered.

Ryuu snorted. "You still don't get it? Your very presence is what allowed Mash to awaken her Noble Phantasm."

"...Did I… really help Mash?"

Ryuu gave her a rare, approving nod.

As the realization settled in, tears welled in Ritsuka's eyes. But this time, they were tears of relief.

Watching the scene unfold, Olga turned away, secretly relieved for them.

"Alright," Ryuu stretched. "Let's find a place to rest and recover."

"Agreed," Cú Chulainn said, rubbing his back. "Damn, my waist is killing me after all that."

"You're way too old to be saying that," Ryuu quipped.

"You little—!"

Mash stirred in Ryuu's arms and spoke softly, "Mr. Ryuu, I can walk on my own now."

"You just burned through all your mana," Ryuu replied. "Take a break."

Mash continued to protest, but Ritsuka and Olga joined in persuading her to rest.

"Yeah, Mash! Just let him carry you for now!"

"I—! B-but…!"

"Hey, I wanna be carried too!" Ritsuka suddenly blurted out.

"You idiot, let Mash rest!" Olga snapped, grabbing Ritsuka's ear and dragging her ahead.

"Ow, ow, ow—Director, that hurts!"

Ryuu chuckled at the ridiculous sight before following after them.

Underneath his composed expression, however, was a glimmer of something more.

Mash Kyrielight—

She was too selfless.

Just like Saber.

She would always put others before herself, never thinking of her own desires.

That flaw would be her downfall someday.

After some time, Cú Chulainn led the group to an abandoned school, securing it as a temporary stronghold.

Ryuu carried Mash to the infirmary and placed her gently on the bed.

He turned to Ritsuka. "Take care of her."

With that, he left.

---

On the Rooftop

Ryuu found Cú Chulainn gazing at the burning cityscape below.

"Not going to check on them?" Cú Chulainn asked.

"They need time to process everything," Ryuu replied.

Cú Chulainn smirked. "You really don't seem like a Demon King, y'know? You're acting more like a hero."

"...I used to be one," Ryuu admitted, his golden eyes glowing faintly. "Before I became the Demon King."

"Then why work with Chaldea?"

"Our interests align. Nothing more."

Cú Chulainn wasn't convinced. But he let it go.

He rested his staff on his shoulders and headed for the stairwell. "Who knows? Maybe you'll become a Heroic Spirit someday."

Ryuu scoffed. "I'm not planning to die. Not until I destroy every single person who betrayed me."

His hatred had not faded.

Even after meeting Mash, Ritsuka, and the others—

His rage still burned.

The false heroes who cast him aside—

The gods who toyed with his fate—

He would kill them all.

No matter what it took.

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