Crossover Shipgirls: Building a Dimensional Empire from Scratch

”The Klaxosaur Princess?! You know about 001?!”

Hearing the Angeloid mention that name, Dr. FRANXX froze in place.

This was top-secret information within City 13—known only to APE and a handful of researchers. No one else had any idea where she was kept.

Years ago, he had been fortunate enough to see the Klaxosaur Princess once in person. She had merely torn off one of his arms… and spared his life.

Using a strand of her hair, Dr. FRANXX had cloned the experimental subject designated 02—the red-skinned, pink-haired little girl with horns from the City 13 laboratory.

He hoped that this clone would one day inherit part of the Klaxosaur Princess’s power, enabling humanity to better combat the klaxosaurs.

”Who exactly are you?! How do you know about her?!”

”Klaxosaurs? No, no… klaxosaurs don’t have humanoid forms~…”

He tried to block the path of one Angeloid, desperate for answers.

”I am under no obligation to answer your questions.”

”Werner FRANXX—you are not listed as a purge target. However, we are authorized to eliminate any interference with Master’s orders.”

The Angeloid pinned him to the floor with one hand.

Though she looked petite, the strength in her slender frame was overwhelming—leaving him completely helpless.

Dr. FRANXX briefly considered calling for security, but the thought died as quickly as it arose.

This was the Central Industrial Zone. For the enemy to have breached it from above and blasted their way into a sealed underground facility, it was clear what had become of City 13’s defense forces.

Then—

Another Angeloid stepped before his computer terminal.

”Requesting data decryption support.”

”Nymph responding~”

Aboard the Aurora, the blue-haired loli angel nodded and tapped the holographic interface.

Whoosh—

The data link synchronized instantly with the Angeloid below.

The most highly encrypted database in City 13—containing detailed records of the klaxosaurs, FRANXX units, and even classified APE research—was completely cracked within seconds.

Hundreds upon hundreds of files were transferred instantly.

Blueprints for mass-produced FRANXX models, as well as unique prototypes like Strelizia, Delphinium, and Argentea—all transmitted in full.

Even experimental technologies still awaiting verification.

Dr. FRANXX’s obsession with science, particularly with klaxosaur biology and technology, had driven him to explore fields far beyond moral or regulatory bounds. His archives included radical theories such as human-klaxosaur hybridization and klaxosaur organ modification—research that even APE had yet to approve for testing.

Now, all of that information was being uploaded to the Angeloids and stored aboard the orbital fleet’s main database.

”Oh, that saves us some effort. With all this data, we won’t need to reverse-engineer anything.”

Observer’s voice came through, clearly impressed by the Angeloids’ efficiency.

It was as if they had just obtained an entirely new tech tree.

”...”

Dr. FRANXX could barely comprehend what was happening. He sat on the ground, staring in disbelief at the graceful yet terrifying angels.

Then his gaze shifted to the hovering shuttles and warships above—technologies utterly beyond anything this world’s humans could construct.

As his mind cleared, realization struck.

”You… you’re from another civilization… out there in space?”

For a scientist of his caliber, it didn’t take long to piece together part of the truth.

”You could say that,” replied the Angeloid, giving instructions while overseeing the recovery of Strelizia.

”!!!”

In that instant, Dr. FRANXX’s scientific fervor ignited like a wildfire.

”Please—take me with you! I beg you!!!”

”I want… to see your ships! Your world! Whatever you want, I’ll give it to you!!!”

He dropped to his knees, blocking their way, pleading earnestly.

”?”

The Angeloid tilted her head in confusion.

It seemed that, across all worlds, every true scientist shared one defining trait—an unquenchable curiosity for the unknown and the pursuit of new technology.

For people like him, their own life—or anyone else’s—meant nothing compared to the pursuit of knowledge. To obtain it, they would sacrifice everything.

”...”

After a brief silence, the Angeloid shook her head.

”Regrettably, your abilities are not sufficient to earn the Commander’s favor.”

Her tone carried the weight of judgment—not only upon him, but upon the entire human race of this world.

”Dr. FRANXX, you are permitted to live. For humanity, that alone is the greatest mercy Master will bestow.”

”Master will end the war between humans and the klaxosaurs. He will bring a new order to this world. All you need to do is accept it.”

”Do not harbor unrealistic ambitions. The Sophon global surveillance network on this planet will be operational within two hours.”

”Be prudent.”

”...”

...

Click—

One hour later.

Aboard the Aurora.

Ikaros stood before Setsuna, bowing respectfully.

”Master, the retrieval of FRANXX units and related research data has been completed. Please confirm.”

”Well done.”

Setsuna patted Ikaros gently on the head.

When venturing beyond worlds, the Angeloids were always his most reliable standard forces—efficient, obedient, and absolutely precise. The mass-production models could handle atmospheric combat with ease, and any issues were quickly resolved by Ikaros or Nymph through their command and electronic warfare capabilities.

”Thank you, Master.”

Though her expression remained calm, a faint blush colored the stoic angel’s cheeks.

...

”Quick! Hurry, Commander, I wanna pilot the new mech!!!”

Gudako tugged impatiently at Setsuna’s sleeve, almost ready to hoist him onto her shoulders.

Inside the hangar, rows of FRANXX units stood proudly in various colors and designs.

At the forefront was the red-and-white Strelizia—the largest and most striking of them all.

Behind it stood the blue-and-white Delphinium wielding dual blades, the pink Argentea, and the black Genista, among others.

”Whoa… it’s even more impressive than Barbatos or Strike Freedom or Turn A, huh?”

Everyone tilted their heads upward to take in the towering sight.

In terms of sheer height, Strelizia was nearly three times the size of Barbatos.

”Of course. It was designed to fight enormous klaxosaurs.”

Setsuna chuckled.

He didn’t particularly need Strelizia—he saw it more as a collectible.

Still, the red-and-white frame was undeniably beautiful.

”?”

One of the shipgirls watching soon noticed something odd.

”Why… does the mech have breasts? …”

All eyes turned to Strelizia’s chest, where the armor curved mysteriously outward.

”Commander, I don’t know much about mech design, but… is that shape really necessary?” Richelieu asked in mild confusion.

”Wouldn’t a sensor array or a missile bay make more sense?”

”Ahem, don’t worry about it. Let’s just say it’s… part of Strelizia’s unique aesthetic.”

Setsuna cleared his throat awkwardly.

Compared to the angular style of Gundams, Strelizia’s curves were… unconventional—but beautiful in their own way.

”Commander, come on! Let’s pilot her already!”

”She looks way cooler than Barbatos!”

Gudako’s eyes sparkled with excitement as she dragged Setsuna toward Strelizia’s cockpit.

”Alright, alright.”

Setsuna decided to give it a try himself.

Thanks to the mech’s massive size, the cockpit interior was far roomier than a typical Gundam’s.

Then, as Gudako stepped inside, she froze.

FRANXX units required one male and one female pilot.

But the Strelizia’s cockpit wasn’t side-by-side… or even front-and-back.

Instead, one person sat… while the other lay forward in front of them.

It looked uncomfortably similar to a motorbike seating arrangement—one that could easily be misinterpreted.

”...Was Dr. FRANXX a pervert?! Why would he design something that looks like a doggy—like a riding position?!”

Fujimaru Ritsuka blurted out, aghast.

”...”

Setsuna ignored the odd phrasing, thinking for a moment.

”According to certain theories, this configuration supposedly helps synchronize the pilots’ mental states—allowing them to merge as one, achieving perfect neural harmony.”

”Merge as one?! That makes it sound even worse!!”

Gudako slapped her forehead in disbelief.

”Whatever. If you can’t accept it, we’ll deal with it later.”

”We’ll send the blueprints to the engineering team—they might be able to make it… less awkward.”

Setsuna shrugged casually.

”...”

Gudako hesitated for a moment.

But in the end, her curiosity for the mech outweighed her embarrassment.

”Fine! So what if I get… a little compromised?! I’m piloting Strelizia!!!”

...

”Commander! Don’t move around!”

Clack—

The two of them slid into the cockpit, each taking up an awkwardly positioned seat.

Inside, Gudako silently cursed the mech’s designer a dozen times over.

”Tch, I’ve seen plenty worse. Nothing to fuss about.”

Setsuna grasped the controls with practiced ease.

Compared to veterans like Taihou, Illustrious, or Formidable, Gudako was still a novice. Setsuna remained perfectly calm, his expression unshaken.

”???”

”You’ve seen worse?!”

Fujimaru Ritsuka felt a strange sense of defeat rising in her chest.

Quickly, though, her focus shifted to Strelizia.

Whoosh—

With a startup chime, the mech’s pure-white face snapped open, revealing a pair of glowing orange eyes. Gradually, facial features emerged.

Strelizia’s expression mirrored that of its pilots—animated even upon its alloy and steel frame, exuding a striking aura of heroism.

”Whoa… this doesn’t feel like a mech at all. More like a mecha-girl?”

Gudako let out a breathless remark. No matter how you looked at it, Strelizia and the rugged Barbatos were from entirely different worlds.

”Piloting a mecha-girl, huh? Not bad.”

The two moved in sync, guiding Strelizia’s massive frame forward step by step.

At first, their movements were a bit stiff.

But both Setsuna and Gudako were seasoned Gundam pilots; within moments they had mastered the basic controls.

The biggest difference between a two-pilot mech and a single-pilot one was simple: their minds had to be synchronized. Without that, even walking in a straight line was impossible.

Setsuna quickly realized he and Gudako were highly compatible.

Within a few maneuvers, Strelizia was moving as smoothly and fluidly as Strike Freedom or Turn A.

Clack—

With a hiss of released locks, the launch bay doors opened. Strelizia leapt from the platform.

Boom—

Its thrusters flared, transitioning into cruise mode.

Like a red meteor, the mech streaked across the sky.

”Hmm… these thrusters need replacing. This is native tech—too slow.”

Setsuna muttered as he piloted.

”And weapons—we’ll need to add some space-combat gear. Micro-arcs, corrosion missiles, gamma lasers, all of it.”

”As for the Queen Pike…”

Clatter—

Strelizia’s fingers tightened on its long spear, pressing a hidden switch.

BOOM!!!—

A searing torrent of energy blasted out from the tip.

This was magma energy—the unique power source of the DITF world.

Even humanity’s elixirs were derived from this same energy.

”If you like close combat, you can keep the spear and shield,” Setsuna mused.

”When we have time, I’ll have the engineering team build another one. We’ll mount a Moonlight Butterfly system on it. Turn A might be ugly, but its power’s no joke.”

Though Setsuna rarely needed to fight in a mech himself, upgrading and modifying them was trivial for the engineering department now.

When he’d swapped Strike Freedom for Turn A, his firepower had skyrocketed—even if its aesthetics had nosedived. This was the perfect time to try something new.

”So, one for each of us? Still, I think we make a good team.”

Gudako leaned forward, muttering as she manipulated the controls.

”Look at us—no training, yet we’re piloting better than any FRANXX pilot in this world.”

”Commander, why don’t you fly Strelizia with me whenever I go fight?”

”Playing house?”

Setsuna chuckled.

”With the time we’d waste piloting together, I could just blast the enemy apart with one shot, couldn’t I?”

”I’ll have a single-pilot version built for you later.”

”Gu…”

Gudako puffed out her cheeks.

”I just wanted you to have fun with me! You’ve been hanging around Fu Hua too long—you’ve turned into a block of wood!!”

”...”

”Fine, then. We’ll keep the cockpit like this. Consider it your… training for the future position.”

”?”

”—Aaaaaaah go die!!!”

...

After cruising through the skies in Strelizia for a while, the two finally satisfied their craving for a new machine.

The red-and-white mech returned to the ship, landing smoothly.

Setsuna and Gudako climbed down from the cockpit as Strelizia’s once-expressive faceplate dimmed, returning to its neutral, emotionless state.

”That was awesome! Way better than Barbatos!”

”Commander, hurry and send her to the engineering department for upgrades! I’m taking Strelizia to the next Singularity to smash some enemies!”

The self-proclaimed ”Human Evil” was practically bouncing with excitement.

Whack—

Setsuna gave her a swift chop to the head.

”Addicted already? That was just a test run. Let’s finish up business here first.”

”Angeloids, retrieve Strelizia.”

He opened his notepad to review the mission status.

They had arrived in the DITF world early—before the main cast had even grown up.

Capturing both the FRANXX units and their future pilots all at once had been simple.

The girls were now under the care of Illustrious and Shoukaku, gradually learning about the wider world and motherhood.

What remained were two primary objectives—the Klaxosaur Princess and the VIRM species.

As for conquering the fortress cities, the Angeloids had that under control.

With each city isolated and communication completely severed, subjugating the DITF world was far simpler than conquering a pre-spacefaring Earth.

”Come to think of it… I recall the Klaxosaur Princess lives underground, doesn’t she?”

Setsuna pondered for a moment, then activated the starship’s sensors.

”All units, initiate deep-scan protocol. Locate the Klaxosaur Princess.”

Whoosh—

The fleet’s starships began sweeping the planet with full-spectrum scans.

On the holographic display, they saw it clearly—beneath the planet’s crust, an enormous number of lifeforms lurked.

They came in countless forms—some as small as cats or dogs, while the largest stretched hundreds of meters long, resembling giant serpents.

”Huh… so these are klaxosaurs? There’s a lot of them…”

Aboard the Aurora, Illustrious stared in astonishment at the readings.

Above ground—human civilization.

Below ground—an entire world of klaxosaurs.

The scanners detected immense energy signatures emanating from the creatures—unimaginable by ordinary biological standards.

”Umm… there are way too many. Commander, what’s the Klaxosaur Princess’s unique signature?”

As the AI attempted to isolate potential targets within the subterranean swarm, Illustrious suddenly gasped.

”Wait—Commander! The klaxosaurs are converging underground toward a single location!!!”

”They’re moving toward City 6—that’s where APE and the Seven Sages are based!!”

From the surface, there was no sign of anything unusual.

But beneath the ground, the scanner displayed a torrent of movement—an underground flood of klaxosaurs, converging from every direction.

The sheer number was incalculable, and their movements were so intense that even the surface cities trembled faintly.

At this point, however, every city was already in chaos, the human defenders overwhelmed by Angeloids—no one noticed the subtle tremors.

Even the automated klaxosaur warning systems had gone offline.

”Tch, so they’re planning to swoop in and claim victory now that humanity’s been beaten into the dirt?”

Setsuna leaned closer to examine the scans, smirking.

The klaxosaurs had fought humanity for years, dwelling deep below the surface.

Now, with the world in chaos and even the FRANXX units reclaimed, they must have sensed the shift in power.

Their counterattack made perfect sense.

”Master, should we intercept them?”

Ikaros asked for orders.

”No. We’ll go see for ourselves.”

With that, Setsuna gave the command.

The Aurora’s engines roared to life, propelling the fleet toward the moving klaxosaur horde.

”Whether they live above or below the surface, all beings on this planet will eventually fall under our order and command.”

”After all… the klaxosaurs are the true natives of this world.”

—

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