Crossover Shipgirls: Building a Dimensional Empire from Scratch

The Synaptic Lathe had been an unexpected gain from this expedition.

Daedalus’ efficiency far exceeded Setsuna’s expectations. Even as the most brilliant scientist of Synapse, she had never encountered such an outrageous concept before.

Thus, Setsuna assigned Grey to oversee the planning and construction of the megastructure—after all, nanobots were natives of the Stellaris world.

As for the ”fuel” required for the mining system...

Setsuna wasn’t too concerned. If necessary, he could always open up more worlds across the star map.

He would personally handle major worlds such as A Certain Magical Index and No Game No Life, while delegating other universes to shipgirls, Heroic Spirits, or human expeditionary squads.

Not only would this strengthen them and fulfill their desire to prove themselves, but it would also conveniently supply more troublesome citizens to burn—extracting every last drop of value from those worlds.

”Additionally, regarding the Microcosm Technology obtained from the Three-Body universe, we’re expanding construction from Units 2 through 5.”

”The planned scale ranges from city-level to continental-level, with corresponding resource consumption and personnel requirements as follows...”

Kayo Senju continued her report on another major research project.

Setsuna skimmed the documents, signed them, and approved both material and Bulin deployment requests.

This groundbreaking technology held enormous potential.

The first Microcosm only encompassed a small city, but if it could be expanded to continental, planetary, or even stellar-system scale, its applications would be limitless.

”Excellent, excellent...”

He spent more time reviewing other progress reports from the Imperial Research Division.

With numerous scientist lolis and top researchers from multiple universes contributing, the Engineering, Physics, and Life Sciences Departments—along with their many subdivisions—were conducting dozens of projects in parallel.

”A nation’s intellect mirrors its lolis; when lolis are wise, the nation thrives.” Setsuna smiled. ”Indeed, the saying holds true.”

After leaving the Research Division, he checked the report feed again before following Purifier’s AI and Observer to a secluded section of the Starbase shipyard.

This area served as the Siren Fleet’s headquarters.

When it came to Azur Lane and Wisdom Cube technologies, such matters were usually left to Akashi or the Sirens themselves—locals always had an advantage when studying their own systems.

After passing through several corridors and halls, Setsuna entered a laboratory.

There, sitting within her jellyfish-like rigging, was a small white-haired Siren girl with golden eyes.

”Commander,” Compiler greeted him without a trace of emotion as she turned around.

”The task you assigned us last time is complete.”

”Following the META blueprint, we successfully extracted and replicated additional META Cubes. They’re ready for deployment.”

Click—

Her massive rigging extended several mechanical arms, retrieving a neatly stacked set of cubes from a device encased in force fields, and placed them before Setsuna.

Unlike the pale-blue Wisdom Cubes, these META Cubes were semi-transparent, glowing in shades of black and crimson.

”Oh...”

Setsuna and the accompanying shipgirls each picked one up. Holding it for just a moment, they could sense the immense, violent power sealed within.

This was the gift presented to him when the Arbiters first arrived at the Starsea Empire—the META Cube, capable of summoning META shipgirls.

They were shipgirls from alternate worldlines—souls who had lost themselves in endless war. Stronger than their normal counterparts, yet far more twisted in nature.

Essentially, they were the dark counterparts of standard shipgirls.

”You worked fast.”

Setsuna smiled. The Experimentals’ efficiency had once again exceeded his expectations.

”The META Cube is, in essence, another form of the Wisdom Cube. Once its core is extracted from the base design, creating a new variant is not difficult,” Compiler replied calmly.

”Hm...”

Formidable leaned closer for a look.

”So, Commander—couldn’t you install one of these yourself? Maybe upgrade the Eternal Snowfall into a META-class vessel?”

Given Setsuna’s tendency to shove random technologies into ship hulls, the suggestion sounded perfectly reasonable.

”The META Cube requires a compatible structural framework. Fusion alone won’t generate a proper vessel.”

”I recommend integrating it into the Eternal Snowfall during its next refit,” Compiler said matter-of-factly.

”...Alright.” Setsuna nodded in agreement.

Setsuna thought for a moment, but he wasn’t in a rush to install another cube just yet.

”Come on, let’s go summon some new wives.”

...

A few minutes later—

Setsuna stood outside the Starbase’s main ship berths. Within the vast dockyard, dozens of vessels of varying sizes awaited—their hulls prepped for the arrival of META shipgirls.

”META shipgirls are essentially counterparts from other worldlines,” explained Observer, perched atop her tentacled rigging. ”Not every shipgirl has a META version. Their fates diverged across timelines.”

She twitched a tentacle. ”But, Commander, you should be cautious. META girls aren’t as easy to handle as normal shipgirls. They all have... issues.”

”I know,” Setsuna replied with a nod.

A large crowd of curious shipgirls had gathered nearby, whispering among themselves.

”Hmm... I wonder what my other self is like.”

”Would she be someone who never met the Commander? Or maybe someone who kept fighting the Sirens all this time?”

Each girl leaned forward, eager and a little nervous, curious to see their alternate selves.

”Alright... Helena, you go first,” Setsuna said, pointing toward the blue-haired shipgirl.

Summoning a META shipgirl required resonance with her original counterpart—two linked consciousnesses acting in sync.

”Eh? Me?”

”Y-Yes, Commander...” Helena stammered, surprised by the sudden nomination.

She stepped beside him, and together, they pressed their palms onto the META Cube, channeling their consciousness inside.

Hum—

Whoosh—

From the META Cube burst a dark red glow.

...

Azur Lane World – A Lost Parallel Universe.

The sea was black, the scent of steel and blood thick in the air.

A small group of shipgirls rested upon floating wreckage scattered across the dark waters.

Their faces resembled those of the Azur Lane fleet, yet none bore the warmth or gentleness of their counterparts. Each carried the look of battle-worn veterans—haunted, exhausted, scarred.

”Phew...”

A blue-haired shipgirl raised her head toward the rust-colored sky.

”The sea is quiet—for now. We’re safe... temporarily.”

Far in the distance, on the horizon, loomed the remains of an island—its skyline shattered and crumbling.

The once-pristine white buildings of the main port lay cleaved in half, the docks and berths in ruins. A torn Azur Lane flag, stained with oil and blood, flapped weakly amidst the rubble.

No life signs remained—only the traces of fire and death.

”This world is breaking down,” muttered another shipgirl, her white hair tied into twin buns beneath a pair of mechanical rabbit ears.

”I can feel the fractures spreading. The rate of collapse is accelerating.”

From far across the ocean came faint cracking sounds—

Tiny shards of reality peeled away like eggshells, leaving only endless void.

”Damn it...”

The shipgirls frowned grimly.

At first, they had fought desperately against the endless enemies rising from the sea, clinging to survival through sheer willpower.

But then... something changed.

The very fabric of space began to unravel. Piece by piece, their world was collapsing.

Soon, the entire ocean would vanish into nothing.

No one knew why.

Some speculated that the universe itself was converging—its worldlines collapsing into a singular timeline.

Whatever the reason, they had no means of stopping it.

”Heh...”

The blue-haired shipgirl gave a bitter laugh.

”So this is our fate... after endless war, we die alongside our world.”

”Fitting, I suppose.”

She tilted her head back, gazing blankly at the fractured sky.

”Enough. Let’s rest for now.”

META Helena sighed softly.

The others—bandaged, weary, still nursing their wounds—nodded silently.

”Is there even a point to fighting anymore? We’re doomed to vanish with this world,” one murmured.

Morale had long since drained from the small squad.

”I’ll scout the southwestern seas later,” META Soryuu said quietly. ”Maybe I can find something... anything.”

”It’s useless,” another replied. ”There’s nothing left—just monsters in the depths. The ports, the fleets... all gone.”

Their voices faded into silence, the weight of despair hanging over them.

”...”

”Hey...”

META Helena looked up at the shattered sky, dazed.

”Do you think... maybe somewhere, there’s a world where the ports never fell? Where everyone laughs together every day?”

”Maybe there’s a Commander—someone powerful enough to lead us all.”

”If there were... maybe everything would’ve been different from the start.”

”Tch—Dreaming again? That’s not like you,” said a shipgirl beside her, an orange ponytail swaying as she rested her sword on her shoulder.

”If that kind of life really existed, it’d have nothing to do with us anymore.”

”Still... who knows?” she added softly, her gaze distant.

Yes—what if there really was another fate waiting out there?

”...”

As they spoke—

Whoosh—

META Helena’s body suddenly glowed with a brilliant crimson light.

”What’s happening...? Wait—someone’s calling me? Who... who is it?!”

Meanwhile—

Inside the shipyard, as Setsuna and Helena poured their energy into the META Cube, a light cruiser was suddenly enveloped in shimmering light. Its form twisted midair, reshaping itself until it finally materialized into a humanoid figure before him.

She looked almost identical to Helena—only her hair was darker, and her eyes gleamed crimson red.

Dressed in a short white jacket and navy-black thigh-high boots, her rigging was a deep jet black. Compared to the gentle and composed Helena, this META Helena radiated a colder, more dangerous aura.

”Brooklyn-class light cruiser Helena—what... is this place?”

META Helena blinked, her expression dazed.

She glanced around in confusion.

Standing before her was a man she didn’t recognize—but through the resonance of the Mind Cube, she instinctively understood he was her Commander.

Surrounding him were numerous shipgirls—and quite a few unfamiliar women, some of whom were clearly Sirens.

In the distance, she could see the brilliance of countless stars. Beneath her feet burned a colossal star, its surface radiating waves of orange fire.

It took her several seconds to realize—she was standing on a massive base built atop the Sun itself.

”???”

META Helena froze completely.

Who am I? Where am I? Why am I suddenly in outer space?!

For a moment, she thought she was hallucinating and quickly ran a self-diagnostic.

”You... uh, hello?”

Helena approached cautiously, extending a hand toward her counterpart.

”I’m Helena, Brooklyn-class light cruiser. It’s nice to meet you...”

”Eh?”

META Helena blinked in confusion. Shaking hands with herself felt absurdly surreal, but out of politeness, she returned the gesture.

”Hello. I’m also Helena. Could you... explain what’s going on here?”

”In short, we were summoning META shipgirls,” Setsuna explained. ”But it seems instead of creating them from scratch, we’ve... pulled you here from another worldline.”

He recalled that when he had summoned younger versions of shipgirls before—like Little Formidable and Little Cheshire—they had been created from zero.

But META shipgirls already existed. The summoning process simply resonated across realities and drew them in from parallel worlds.

”Yes... I see,” META Helena nodded. ”I was with Soryuu and Hiryuu, making repairs, when I suddenly felt a strange pull...”

She briefly described her situation on the other side.

”Oh, Commander, looks like we should hurry it up,” Observer muttered, poking Setsuna lightly with a tentacle.

”Their experimental field is collapsing. Aside from a few exceptions, most META shipgirls don’t possess the Arbiters’ ability to survive or travel through the void.”

”We should bring them over as quickly as possible.”

”...”

”Alright.”

Since Setsuna himself had been the indirect cause of that worldline’s collapse, he quickly arranged for META Helena to be escorted by others.

He then glanced down at the summoning roster.

”Next one... META Prestige. Come summon with me.”

”Understood, Commander.”

The blonde, blue-eyed shipgirl stepped forward. Together, they pressed their hands onto the Cube and channeled energy.

Hum—

A crimson flash erupted.

A golden-haired shipgirl materialized before them, a long sword in her hand, her expression sharp and commanding.

”Whoa—Saberface?!”

Setsuna almost mistook her for a certain famously gluttonous king from another universe.

”Hm? Where... is this? Helena? You’re here too?”

”We were just worrying about where you’d gone!”

META Prestige looked just as bewildered, realizing she’d been reunited with the Helena who had vanished moments ago.

”I’ll explain later,” Setsuna said, clearing his throat. ”Next one.”

He scrolled further down the list.

”Erebus.”

”Coming~!”

Whoosh—

A petite girl in a black camisole and stockings, carrying a massive scythe, landed lightly on the ground.

”Take her away. Next—Sheffield.”

”Yes, Commander.”

...

About an hour later—

Within the vast shipyard of the Starbase, dozens of META shipgirls now stood in formation.

Every name on the summoning list had been called, and every META counterpart had answered.

Compared to the Azur Lane port’s shipgirls, the META girls carried a heavier, gloomier air. Their outfits were uniformly dark-toned, their expressions sharp and wary.

The regular shipgirls and their META selves studied one another curiously.

”Hmm... so you’re another version of me? What happened in your world?”

Queen Elizabeth peered at the silver-haired, red-eyed version of herself wearing an elegant black gown. Her META self exuded a regal authority untouched by naivety—a queen to the core, though more austere and brooding.

”We come from a world where the port fell—where there was no hope, no future,” META Prestige answered in her stead. ”All that remained was endless war. But this place... what is it?”

Some META shipgirls hailed from different worldlines, but all their stories were alike—worlds ravaged by ceaseless conflict.

Dragged by an unknown force into a strange new realm, they were understandably confused.

”Alright,” Setsuna said after a moment’s thought. ”I’ll make this simple.”

”This is the Starsea Empire. I’m the Commander of the Azur Lane fleet—and the Siren Fleet is also part of our forces here.”

”We used Arbiter and META Cube technology to pull you in from your collapsing parallel universes. Fortunately, we made it in time before those worlds completely broke down.”

”In the future, you’ll live alongside the regular Azur Lane shipgirls. Richelieu and Yat Sen will handle your orientation and answer any questions.”

”???”

The META shipgirls were left speechless.

The sheer amount of information in his words was overwhelming. Whatever thoughts of war or vengeance they’d held vanished instantly, replaced by confusion and disbelief.

Another world?

They’d been summoned to space?

The sky wasn’t even blue—it was full of stars?!

And wait—the Arbiters? Wasn’t that the enemy—the Sirens themselves?!

Why were they standing here... on friendly terms with their Commander?!

”Ah, they’re stunned,” Formidable remarked, shrugging.

”Same as all the other natives when they first arrived in the Starsea Empire.”

...

Another hour passed before the META shipgirls from across the multiverse finally came to terms with reality.

They sat before Setsuna, still wide-eyed, glancing between him and the shipgirls around him.

So this is another possible version of our Commander...

They had once imagined that if a perfect, powerful Commander truly existed, he would lead them to defeat the Sirens and restore peace to the ports.

Yet here stood a version of him who had transcended even that—leading fleets through the stars, waging interstellar wars across the multiverse.

It was... beyond comprehension.

Several META shipgirls began to question their very existence.

All that endless fighting... for what?

The Sirens—weren’t they supposed to be our mortal enemies?

But that same Observer was now sitting beside the Commander, teasing him playfully with her tentacles.

”Ahem. Anyway, welcome to the Starsea Empire,” Setsuna said, smiling warmly. ”I hope you’ll adapt quickly to life here. If you need anything, don’t hesitate to contact me.”

”...”

The group fell silent for a brief moment—still slightly disoriented by their situation.

”I... I understand,” said META Ark Royal at last, standing at attention. ”I shall continue to fight as a weapon of war.”

She hesitated before adding, ”Though... may I request a destroyer escort? Or perhaps any mission—you may deploy me at once.”

”You really haven’t changed, have you,” Bismarck muttered with a helpless look.

”Since it’s your first offense, I’ll overlook it. But if you repeat this behavior, next time you’re getting locked up—with Royal Ark as your cellmate.”

”Tch. You could always be your own jailer,” Formidable quipped under her breath.

—

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