Crossover Shipgirls: Building a Dimensional Empire from Scratch

After a simple cleanup of the battlefield and reformation of the ranks, the starship once again entered faster-than-light travel, performing consecutive FTL jumps.

Information-based lifeforms—energy beings of thought and data—sounded sophisticated at first glance.

But when faced with a civilization far superior in technological hierarchy, a huge problem arose:

Everyone relied on technology, yet the higher civilization had the complete ability to crush the natives.

They had transformed themselves into virtual entities made of pure energy and data, but if their opponent’s information warfare capabilities surpassed theirs, their entire civilization would become nothing more than a fuzzy toy in the enemy’s hands.

It was like turning oneself into a robot, believing that by abandoning the fragile flesh one had become a higher form of life—only to be hacked by a superior civilization and turned into a puppet.

”We’ve intercepted some interesting VIRM data. After discovering that the Seven Sages were eliminated, they’ve started mobilizing fleets toward Earth.”

”Oh? Too bad we caught them first.”

Countless streams of data flashed before Nymph.

”Commander, there appears to be a hidden VIRM scout fleet located some distance outside the Solar System.”

”The same one that invaded Earth in the original story? Should we interfere?”

The Angeloid had completely decoded the enemy’s communications; the entire civilization lay bare before her eyes, without secrets.

”Scout fleet? Have the Third Earth Defense Squadron send a team to deal with them.”

Setsuna replied casually.

”They’ve been idle guarding Earth anyway. Time for some exercise.”

”Roger that!!!”

Cheerful shouts came through the communicator from the shipgirls.

”Commander, should we capture some of them alive for research?”

”If you’re bored, sure—but remember, they’re incorporeal lifeforms. Be careful how you capture them.”

Whoosh—

Whoosh—

Soon, after several jumps, the target star system appeared projected on the starmap.

It was a typical A-type star, with several planets slowly orbiting around it.

Within the system, a few mining stations and small ships could be seen—proof that its inhabitants had already entered the space age.

”Tch, so this is the VIRM homeworld? Looks about the same as in the original story.”

Setsuna scanned the star system’s layout.

Among the planets, the largest rocky one was the VIRM homeworld, covered with peculiar structures whose purposes were indecipherable.

Since they were information-based lifeforms, their architectural concepts naturally differed vastly from those of organic beings.

”VIRM…”

The Klaxosaur Princess clenched her fists tightly, her mandible-like appendages behind her twitching in agitation.

During her thousands—no, millions—of years of hibernation underground, she had dreamed countless times of revenge.

But due to the massive difference in power between them, she could barely protect Earth, let alone strike back at the VIRM.

Now, Setsuna had given her the chance to confront her ancient nemesis face to face.

”Please… completely annihilate them. Otherwise, the VIRM will surely return one day.”

The Klaxosaur Princess spoke solemnly.

”Of course. We’re not lacking in planet-killing methods.”

Setsuna smiled.

”Hmm… considering Photoid velocity is a bit slow, I’ll handle this myself. The sooner we’re done, the sooner we can go home.”

Clack—

The main cannon of the Eternal Snowfall began to charge.

[Fallen Star Lance charging: 30%... 45%...]

Brilliant light radiated from the axis weapon, awe-inspiring to behold.

...

Within the VIRM system, various defense platforms hovered in orbit, while a few remaining fleets patrolled nearby.

In space warfare, once the main fleet was annihilated, an entire civilization effectively became lambs waiting for slaughter.

Without the ability to resist, the victors could do whatever they pleased.

Still, the VIRM wanted to make one last effort—to identify who these mysterious ships were and where they had come from.

[Beep—]

A signal connected to the Eternal Snowfall’s comms.

A glowing energy sphere-like lifeform was projected before them.

”Who are you?”

”Starsea Empire.”

Setsuna replied expressionlessly.

”Where do you come from? Why are you attacking us?”

The VIRM consciousness questioned Setsuna.

”No reason.”

Setsuna answered lazily, glancing at the charging progress bar.

To a civilization that was about to be wiped out, there was nothing worth explaining. He only wanted to hear what they had to say before the end.

”…Because we attacked the humans and the Klaxosaurs?”

The VIRM’s upper consciousness quickly simulated several possibilities.

”We should maintain peace. I can surrender the Solar System to you.”

”From this day on, we will no longer invade Earth, and we will abandon the assimilation plan for humanity.”

”You may be stronger, but you are still inferior to organic life. If we cooperate, we can—”

Another message was transmitted through the channel.

”?”

”Reconciliation? Now? Are you kidding me?”

Setsuna almost laughed.

”I didn’t expect you to have a sense of humor.”

”...”

The other side still tried to explain further, but he cut them off with a wave of his hand.

”Countdown—five seconds. Farewell.”

...

BOOM!!!—

The Fallen Star Lance, wrapped in overwhelming energy, tore through the darkness of space.

At nearly immeasurable velocity, it struck the VIRM homeworld.

Though designed as a star-level weapon, it could also be fired directly at planets when necessary.

A light spear over a hundred kilometers wide pierced through the planet’s entire surface and mantle in an instant.

From outer space, it looked as if the entire world had been skewered through its core.

The immense radiation released by the blast obliterated all life on the surface.

The VIRM, being energy-based lifeforms without physical bodies, were immune to conventional attacks like kinetic weapons or missiles—but when faced with ultra-high-energy bombardment, they were equally fragile.

The chaotic surge of energy destabilized their very existence, erasing countless consciousnesses within seconds.

Then—

As the planet’s core suffered catastrophic shock and its geological structure destabilized—

Crack—

BOOM!

In a series of deafening explosions, the entire planet shattered into pieces.

Tectonic plates and crustal layers were ripped apart, fragments scattering in every direction.

Molten magma was hurled into space, rapidly cooling and solidifying into drifting rock.

No matter how glorious the VIRM civilization had once been, nor how intricate their defenses—

Before a planet-breaking strike, everything was meaningless.

In the void, aside from fragments of the shattered world, only a few remnants of their structures remained, orbiting the debris field.

”Ah…”

Witnessing the death of an entire planet was an awe-inspiring sight.

The Klaxosaur Princess’ expression turned dazed.

The VIRM—who had warred against her kind for tens of millions of years—hadn’t even managed to finish a proper conversation before being completely annihilated.

She couldn’t help but feel relieved that she hadn’t attacked Setsuna upon their first meeting.

Otherwise, Earth might have shared the same fate.

”Uh…”

Her throat felt dry.

Setsuna patted her on the shoulder.

”Scared?”

”…A little. I’ve never seen such a weapon before.”

The Klaxosaur Princess nodded slightly.

”It’s fine. You’ll get used to it after seeing it a few more times. There’ll be plenty of opportunities in the future.”

Setsuna replied calmly.

”?”

”Something like this… you can get used to?!”

After shattering the VIRM homeworld, the shipgirls accompanying the Eternal Snowfall reignited their engines, pursuing and annihilating the remnants. Every surviving VIRM vessel and orbital facility was systematically destroyed.

[Beep—]

Setsuna activated the Eternal Snowfall’s sensors and scanned the surroundings.

Just like in the original story, aside from their home system, the VIRM had no other colonies. Only scattered fleets drifted nearby—insignificant, soon to be erased by the shipgirls.

”Hmm, they seem to only have this one planet? Strange…”

”Rather than calling them an interstellar civilization, they’re more like primitives who just recently reached space.”

Considering they had only one star system, it was bizarre that the VIRM spent such immense effort and energy to cross interstellar distances to invade Earth— infiltrating humanity’s highest ranks and instigating conflict between humans and the Klaxosaurs.

Setsuna couldn’t comprehend their obsession. Their determination was… impressive, if nothing else.

”Master, rather than saying the VIRM invaded Earth, it would be more accurate to say they wanted to assimilate it,” Nymph commented, fingers dancing across her holographic console.

”During your brief conversation with them earlier, I finished decrypting the VIRM’s information network and computer systems.”

”Their goal wasn’t resources or territory—it was to turn humanity into the same kind of lifeform as themselves.”

”???”

Setsuna vaguely recalled this plot point—it was mentioned briefly in the original work.

The Klaxosaur Princess and the shipgirls leaned forward, looking as if they’d just heard nonsense.

”Huh? Assimilate? What does that even mean?”

”They called us ’organic lifeforms’ earlier, right? And they even invited the Commander to join them.”

Nymph swiped through several panels, bringing up data streams.

”The VIRM became pure consciousness lifeforms ages ago. They firmly believe that this is the ultimate form of existence.”

”Conscious beings freed from physical form can exist eternally in the universe.”

”And the VIRM seek to assimilate other civilizations into this same state. When they discovered the Solar System, they began their invasion of Earth.”

”Their first assimilation target was the Klaxosaurs, but due to fierce resistance, they failed. Later, they decided to manipulate humanity to conquer Earth and assimilate both humans and Klaxosaurs together.”

”...”

”Uh…”

It took a while for those without Nymph’s computational capacity to process the translated data.

Gudako and the Klaxosaur Princess rubbed their temples in pain.

”So you’re telling me they went through all that trouble… just to turn us into the same kind of thought-blob as them? Immortal energy ghosts?”

”You could say that. Consciousness-based civilizations are structured differently from organic ones,” Nymph explained thoughtfully.

”In a civilization composed entirely of thoughtforms, every consciousness is both an individual and part of the whole. They can act independently or merge together.”

”According to the VIRM, once physical bodies are abandoned, existence becomes perfect—differences, greed, and ambition all vanish. The scattered individuals unite into a single being.”

”So, the VIRM’s ultimate goal was to absorb both human and Klaxosaur civilizations into themselves completely.”

”No wonder they weren’t interested in resources or magma energy—they only cared about humanity and the Klaxosaurs.”

”...”

Gudako thought for a moment, then rolled her eyes.

”Who cares? Evil aliens are evil aliens. Whatever their true intentions were, they’ve already been blasted into cosmic dust by the Commander.”

”Problem solved. That’s what matters.”

”As expected of you.”

The shipgirls nodded in admiration.

She didn’t need to know who she was, nor what the enemy wanted. All that mattered was clearing whatever stood in her path.

A war criminal from Paradox and the embodiment of Human Evil—truly a match made in heaven.

”So basically, they were… assimilation warriors?”

Setsuna froze for a moment—then nearly spat out his drink.

In Stellaris, there were civilizations that sought to transform all organic life into mechanical intelligences—assimilationists who erased the boundary between flesh and machine.

The VIRM were basically the same, except their version turned everyone into pure consciousness.

”Exactly. That’s what their records indicate,” Nymph confirmed, pulling up several files.

”Commander, I even found detailed data on their assimilation procedure—how they convert organic lifeforms into energy beings…”

”With our technology, it wouldn’t take long to decipher. If Master wants, we could even attempt—”

”No.”

The other shipgirls immediately refused.

”Who the hell wants to turn into a bodiless blob of energy?! I’m perfectly fine as I am.”

”Yeah! And they weren’t even that strong—so what if they’re immune to kinetic and missile attacks? They still got skewered by the tachyon lance!”

Most shipgirls were quite satisfied with their physical forms. Even the few aircraft carriers who occasionally complained about their flight decks didn’t want to become intangible.

After all, they were at least aircraft carriers now—if they turned into energy beings, they’d literally become… air.

”...”

Setsuna, however, was thinking of something else entirely.

”Wait—returning humanity from individuals to a unified collective… eliminating division, merging all into one?”

”Isn’t that basically another version of the Human Instrumentality Project?! No wonder the VIRM felt so familiar!”

”?”

”What’s the Human Instrumentality Project?” the others asked curiously.

”Ahem… let’s just say it’s a plan to turn humanity into orange juice. Not important. You’ll understand once we visit the EVA world someday…”

...

It took the Angeloid and the shipgirls half a day to sweep the entire system clean.

The VIRM’s technological level was far inferior to that of the Starsea Empire—there was nothing of real value to salvage.

That was why Setsuna had simply destroyed their homeworld from the start.

Only a few data-based lifeforms, like the Seven Sages and the scout fleet, were captured by Nymph for research.

After clearing the remaining ships and collecting some information, the fleet performed several warp jumps and returned to Earth.

Boom—

The Eternal Snowfall slowly descended into Earth’s orbit.

From the fortress cities below, it looked as though an enormous new moon had appeared in the sky.

The weaponized wings of dark alloy dominated the heavens, so vast that even gazing upon them made one’s knees go weak.

”Reporting, Commander—during your absence, Earth has been fully integrated under the administration of the Starsea Empire.”

”Sophons are currently establishing an administrative network.”

A blonde, blue-eyed shipgirl in uniform reported crisply. Beside her stood another—silver-haired, blue-eyed, equally dignified.

Bismarck and Tirpitz.

Both known for their discipline and military expertise, they were Setsuna’s go-to commanders for planetary occupation and reorganization.

”Good work,” Setsuna nodded.

”However… we haven’t dealt with the Klaxosaurs yet,” Bismarck said cautiously.

”Some humans still harbor intense hostility toward them. They’ve requested that Sophons deploy forces to eliminate the Klaxosaurs for the sake of urban safety.”

”Given that the Klaxosaurs haven’t attacked us or any cities—and considering the Klaxosaur Princess’ connection—we declined for now. What are your orders?”

Her gaze shifted subtly toward the Klaxosaur Princess.

On an ordinary world, such creatures would’ve been exterminated without question. But the DITF world was special—they had to handle things differently.

”From now on, humans and Klaxosaurs will live peacefully. No one is to cause trouble,” Setsuna said, glancing at the Klaxosaur Princess.

”I’ll designate a protected zone for them. Humans can mine off-world resources; the Klaxosaurs will remain on Earth for now.”

”...”

The Klaxosaur Princess thought for a moment, then nodded slowly.

”Understood.”

With the VIRM gone, a heavy weight had finally lifted from her shoulders. The war that had lasted millions of years was over—and in the sudden calm that followed, an unfamiliar emptiness crept in.

”Hmm…”

Gudako rubbed her chin, studying her.

”So, you’re the last Klaxosaur-human, huh? This is starting to sound like a ’fallen princess of a lost race’ kind of story.”

”To rebuild your species, I suggest you cling tightly to the Commander’s thigh—and maybe see if humans and aliens can even have kids…”

Bonk—

”Why’d you hit me?!”

”????”

—

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