In DxD Starting with Sign-Ing in as the Red Dragon

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Juggernaut Drive!

The forbidden technique of fully unleashing the dragon's soul!

Every generation of hosts for the Two Heavenly Dragons faces the pitfalls left by countless predecessors.

The fate of the Two Heavenly Dragons' hosts has often been grim, with most meeting their end due to the reckless use of Juggernaut Drive.

Thus, the Boosted Gear and the Divine Dividing are filled with immense resentment.

If a host of the Two Heavenly Dragons is mediocre in talent, they are likely to be driven mad by this resentment, falling into a state of uncontrollable Juggernaut Drive, ultimately draining their life force and perishing.

Only someone like Vali, with his mixed heritage of human and demon blood, can use magic to substitute for life force, allowing him to wield Juggernaut Drive so freely.

But now, there is another who can use Juggernaut Drive without harm!

Moreover, Akira can sustain Juggernaut Drive by expending either "chaos energy" or his physical stamina!

In this state, even in a battle of Juggernaut Drives, Akira can outlast his opponents!

Super Devil!

In his Juggernaut Drive state, Akira can tap into a portion of the Red Dragon Emperor's power, stabilizing his overall strength at the level of a Super Devil!

Only in this state can Akira withstand the "world's collapse" and repair the world!

Whoosh!

The wings of the Red Dragon Emperor spread wide, revealing twelve draconic wings, each adorned with several green jewels.

ROOOOOAR!

A deafening dragon's roar echoed as the jewels on Akira's dragon form began to glow brightly.

[Boost! Boost! Boost! Boost! Boost! Boost!]

As the green jewels flashed, Akira's chest began to gather dimensional energy.

If this were the DxD world, Akira wouldn't dare to so blatantly use such high-level dimensional energy. But in the Fate world, he had no such reservations.

Outside the World.

Akira's body acted like a black hole, endlessly absorbing dimensional energy from the void and concentrating it in his chest.

Due to Alaya's interference, the world was gradually collapsing, transforming into "world fragments."

As the world crumbled, these fragments were broken down into dimensional energy by dimensional creatures.

Akira, however, sought to reverse this process! He aimed to absorb dimensional energy and use it to repair the world!

Dimensional energy was infinite.

Within the dimensional void, Akira's capacity to endure had increased significantly, allowing him to continuously gather dimensional energy.

[How is this possible?] Agumon gulped.

He had thought Akira was already incredibly strong, but within the dimensional void, Akira's power surpassed even that of the normal world.

Under Agumon's watchful gaze, the energy in Akira's chest reached its limit.

[Ouroboros • Longinus-Smasher!]

[Chaos • Divine Destruction Cannon!]

BOOM!

A pure beam of dimensional energy erupted from Akira!

The [Divine Destruction Cannon] was a powerful attack that could only be used by the Boosted Gear in special modes.

Normally, it could only be activated in [Juggernaut Drive], [Great-Red Fusion], or [Dragon God Mode].

However, [Great-Red Fusion] required the power of the Red Dragon Emperor, and [Dragon God Mode] needed the combined power of Ophis and the Red Dragon Emperor.

Before unlocking these stronger modes, using [Juggernaut Drive] to activate the [Divine Destruction Cannon] was the only solution!

When Issei Hyoudou used this attack in his semi-Juggernaut Drive state, he effortlessly annihilated the old demon king, Shalba Beelzebub.

But what Akira faced now was... a world being devoured by the dimensional void!

The color of the dimensional energy was unique, resembling a fusion of crystal and chaos, transparent yet shimmering with a kaleidoscope of colors that were occasionally swallowed by darkness.

Under the influence of this uniquely colored "cannon," the Fate world's collapse was halted.

But... this alone wasn't enough!

[Agumon!] Akira called out.

[Understood, Akira!]

Agumon quickly snapped out of his shock and responded to Akira's call.

[Armor Evolution!—]

[Holy Armor—Shield of Courage and Faith!]

Agumon transformed into a golden light that enveloped Akira.

Soon, Akira held a large, intricately designed shield, and his aura grew even more formidable.

"HAAAAAAAAAA!"

Akira and Agumon combined their strength, pushing the rate of dimensional energy conversion to its limit!

Finally, under the overwhelming force of the dimensional energy, the world's collapse began to reverse!

The fragments of the world began to reform, and the dimensional rifts were steadily being sealed!

And so, Akira and Agumon maintained the [Divine Destruction Cannon] for half an hour!

After half an hour of continuous dimensional energy infusion, the world was restored to its original state!

But even after repairing the world, Akira wasn't done yet!

"Agumon!"

[Understood, Akira!]

Akira raised his hand, and the shield began to expand.

Ten meters, a hundred meters, a thousand meters... a million meters, ten million meters!

The shield grew until it was large enough to cover the entire world!

Agumon's Holy Armor had two modes.

In its spear form, the "Spear that Pierces the World," it possessed the power to destroy other worlds.

In its shield form, the "Shield of Courage and Faith," it had the power to protect its own world!

This was the very purpose for which Agumon had been created!

[Seven days, Akira. I can maintain this for seven days at most.]

[During these seven days, our world will be safe from any external threats.]

"Understood, Agumon," Akira nodded.

"Tonight, the Holy Grail War will end."

Once the Holy Grail War concluded, Akira would obtain the item needed to fully restore Agumon's foundation!

With his foundation restored, Agumon could maintain his form for even longer.

As for Akira, he planned to use this time to gather enough fate energy to complete the world's conquest.

Once the world was conquered, he could take this world with him.

"By the way, Agumon, can you leave three channels open?"

[Huh? I can, but why?]

"I want to give MarineDevimon a place to level up."

"On one hand, MarineDevimon can grow stronger."

"On the other hand, it will relieve some of your burden."

[True. It's better to divert than to block. If I can open some restrictions in uninhabited areas, my burden will lessen, and I can last longer.] Agumon nodded.

"Then it's settled."

"As MarineDevimon grows stronger, you can open even more restrictions, further reducing your burden."

[Understood, Akira!]

[If I'm going to open some dimensional rifts, I'll place them in these locations...]

Soon, Agumon sent Akira a list of uninhabited areas.

"Good. I'll wrap up the Holy Grail War and conquer this world as quickly as possible."

With that, Akira's figure gradually faded, disappearing into the dimensional void.

After sealing the channels that allowed the sea demons and dimensional creatures to invade, Akira returned to the Fate world to clean up the remaining invaders.

Two hours later, the massive sea demons invading the Fate world were completely eradicated.

MarineDevimon, having absorbed countless sea demons tainted with outer god energy, had broken through to the Super Devil level, becoming a monstrous entity rivaling the original Four Great Satans!

"Return!"

Akira recalled MarineDevimon like a Pokémon and used his dimensional abilities to transport it to Agumon's coordinates.

"With MarineDevimon handling some of the sea demons and dimensional creatures, Agumon can hold out longer."

Half an hour later, Akira sent away the last of the invading dimensional creatures.

Dimensional creatures were more slippery than sea demons, so it took a bit longer to deal with the final one.

After sending the last dimensional creature to his "battery space," Akira heard the system's notification.

[Ding!]

[Congratulations, Host, on completing the Villain Check-in!]

[Check-in Level: Gold.]

[Check-in Type: Event Check-in.]

[Check-in Event: Expelling Foreign Creatures.]

[Requirement: Completely eliminate the invading outer god minions and dimensional creatures.]

[Congratulations, Host, on receiving the reward: Fate Concealer.]

[Fate Concealer: A device that can hide the fate energy of a designated target. With this, you can deceive the world, alter predetermined destinies, and absorb the world's fate energy without being detected by the world's consciousness.]

If Akira had possessed the Fate Concealer earlier, he wouldn't have been expelled for absorbing Rin Tohsaka's fate energy.

If the God of the Bible had possessed the Fate Concealer, he wouldn't have met his inevitable death.

"The God of the Bible... an inevitable death."

Hearing this unexpected revelation, Akira's expression turned slightly complicated.

After traveling around the world, Akira returned to the Einzbern Castle.

Originally, he had planned to meet with Ayako Mitsuzuri and Taiga Fujimura to boost their affection levels.

But as soon as he returned, he was intercepted by a certain twin-tailed girl.

"Hey! Akira! Demon King Akira!"

Rin Tohsaka called out to Akira as he returned.

"Rin... you're looking for me?"

Akira was slightly surprised and looked at Rin with a caring gaze.

He noticed that Rin's emotions were unusually unstable, unlike her usual self.

"Don't look at me like that! I'm not your daughter!"

Rin hated the way Akira looked at her, as if he were her father.

She may have lost her father, but she wasn't like Sakura, who had come to see Akira as her "dad."

Sakura saw Akira as her father because he had saved her.

But Akira hadn't saved Rin, so why should she see him as a father?

"Rin. Is this the etiquette your mother taught you? To be respectful to your elders?"

Akira smiled, continuing to speak in a fatherly tone.

"Shut up!"

Rin flicked her twin tails in frustration.

"I told you! You're not my father! I won't treat you like an elder!"

As she spoke, Rin closed the distance between them, bringing their faces within inches of each other.

"Demon King Akira, I want to make a deal with you!"

"What kind of deal?"

Akira looked into Rin's beautiful blue eyes.

At this distance, one would expect either a kiss or a fight.

But Rin was different. She had closed the distance for another reason.

Thump... thump... thump...

Feeling her heart race, Rin took a deep breath to steady herself.

"Sakura has made a contract with you, right?"

"Release Sakura from that contract and set her free."

"In exchange, I will make a contract with you."

"I've heard about our special nature. If Sakura can make a contract with you, then so can I."

This... was Rin's way of atoning.

She wanted to go a step further than Sakura's suggestion!

Rather than sharing ownership with Sakura as demons, Rin wanted to free Sakura and bear the burden herself!

Akira, feeling Rin's warm breath, gently placed a finger on her forehead.

"Sorry, but I don't offer refunds."

"Besides, I believe that once you understand the current situation, you'll willingly make a contract with me."

"Huh? What do you mean? What do you mean by 'once I understand the current situation'?"

"Just this."

Whoosh!

A golden light emanated from Akira's hand.

In an instant, Akira transmitted the recent events directly into Rin's mind.

"This is..."

Rin's worldview was completely shattered as she processed the information.

While Rin was digesting the information, Akira received a message from Sakura.

[Akira, my sister has been troubled lately. So, I gave her some psychological counseling.]

[Now, it seems she's decided to atone by making a contract with you.]

"Psychological counseling, huh..."

Akira raised an eyebrow.

Sakura's "counseling" seemed more like psychological manipulation.

But since the outcome benefited him, Akira wasn't about to tell Rin, "She's manipulating you!"

Note: So far this story is published up to chapter 125 on my patreon, go check it out and remember that if we reach the goal of 150 power stones I will publish the next chapter.