Crossover Shipgirls: Building a Dimensional Empire from Scratch

[Alert!]

[Starsea Empire vessel detected beyond the outer edge of the star system!!]

The moment the alarm sounded.

Oswaldo and the entire star system immediately entered a state of high alert.

The gravitational field interference devices were activated at full power. In an instant, severe distortions in the force fields rippled throughout the system, preparing to deflect the trajectories of incoming Photoids.

Warships split into smaller squadrons along the orbits of several planets, advancing to positions slightly farther from the sun to avoid being caught in the blast if the star were shattered due to interception failure.

All weapons across the fleet were readied. Along with Oswaldo, every employee and every soldier aboard the ships stared tensely at the distant sky.

”Are they coming?”

Some gripped their weapons. Others stared unblinkingly at the starship sensors. Even the crew members were fully prepared.

They were determined to respond at the very first moment of a Photoid strike and engage the Starsea Empire fleet that would follow.

”...”

Time seemed to crawl at this moment.

Oswaldo kept his eyes fixed on the dark expanse at the far end of the system. Even as his vision grew fatigued, the anticipated meteor shower of Photoids did not appear.

”Where is their fleet?”

”Are our targeting systems insufficient? Did they activate cloaking technology?”

Cold sweat trickled down a subordinate’s face as he urgently contacted more than a dozen combat squads. Sensors scanned this region of space and most of the surrounding area.

They reached an unbelievable conclusion.

”No...”

”The Starsea Empire sent only a single vessel. It jumped to a nearby system not long ago and skimmed past the edge of this system at light speed.”

”That ship is different from the thirty Emanators we’ve previously seen. It did not appear in earlier battles, nor did it fire any Photoids.”

The design style of a Siren warship was vastly different from that of a shipgirl. It could be identified at a glance.

”What is it doing here?”

Oswaldo asked. Common sense told him that a Starsea Empire vessel would not come merely to offer greetings.

Nor would it be for reconnaissance. The enemy possessed some method of observing information from higher dimensions, almost like having the entire map revealed.

”We don’t know. It seemed to simply pass by...”

”No, that’s not right. It didn’t fire Photoids—but it launched something else at us.”

The gravitational wave early-warning devices within the system detected an anomaly.

According to observational data, a peculiar object had passed in from beyond the system.

Even the Subspace Crystalline Barrier and the Celestial Comet Wall failed to stop it. The Imaginary barrier was as if nonexistent to it.

”Technical team!!”

Oswaldo shouted.

Within half an hour, they analyzed the object’s trajectory.

As the sheet entered the star system, its speed sharply decreased to one-thousandth the speed of light—and it continued to slow.

This brought some relief. At such a low speed, it posed no threat to the sun. There would be ample reaction time.

The sheet gradually decelerated, slower and slower, until it hovered near the orbit of a planet at the outer edge of the system.

Its volume was so minuscule against the vastness of space, and combined with its semi-transparent coloration, it was nearly impossible to see with the naked eye.

Only through gravitational waves could its position be barely determined.

”What is this?”

At first, the system remained on high alert.

They had imagined being struck by hundreds of Photoids, thirty Emanators appearing before them, and a battle that would darken the heavens.

They had never anticipated that the enemy would send something completely unrelated.

”Oswaldo, what’s the situation?”

From a location somewhat distant from this system, the voice of Mtooyin Raj Zazzad came through.

Executives from departments such as the Talent Motivation Department and the Traditional Project Department were each stationed at critical nodes nearby.

If nothing unexpected occurred, this Marketing Development Department director would be the first to confront the Starsea Empire.

”We encountered a Starsea Empire vessel, but no combat occurred.”

”They launched... well, I don’t know what this thing is. The technical team and reconnaissance team are preparing to approach and investigate.”

”The same here. The Starsea Empire ship did not engage in battle. It launched an unknown object at us.”

Mtooyin Raj Zazzad said.

At every node star system where the Interastral Peace Corporation had deployed defenses, each fleet on high alert had received this exceedingly strange object.

After the lesson of the Photoids, no one dared act rashly.

”Observe it first. Be careful.”

”We’ll go in first. You prepare to retreat at any time.”

Oswaldo ordered two smaller ships to approach the ”sheet.”

Aboard them were reconnaissance and technical teams from the Interastral Peace Corporation.

This sort of near-suicidal task came with extremely generous compensation. The director promised to promote them directly to P36 rank and transfer them from branch offices straight into headquarters.

Members of the Genius Society provided remote consultation, guiding the teams in real time through holographic interfaces.

”Pull back.”

After a moment’s thought, Oswaldo, exercising caution, ordered the fleet to withdraw to the opposite end of the system.

Now a vast portion of the system and an entire sun lay between them. Hundreds of millions of kilometers gave him a measure of reassurance.

Even if a concentrated Photoid strike occurred again, there would be sufficient time to respond.

Click—

The technical team’s ship attempted to use a mechanical arm to tow the sheet inside.

Clack!

Something strange happened. As the arm retracted, the sheet slipped out from the enclosed claw and continued hovering in place, utterly unmoved.

”Hm?”

The projection of Dr. Ratio appeared.

He was observing the situation from countless star systems away, offering suggestions to the Research Division while also taking the opportunity to see something new.

”Strange. It doesn’t seem to be a physical entity...”

Dr. Ratio leaned so close to the holographic interface it seemed as though his head might emerge from it, trying to see more clearly.

The corporation’s ship tried repeatedly—mechanical arms, robots, various devices—but none could interact with the sheet.

Several crew members even swept laser weapons straight through the middle of it. Nothing happened.

”Lower altitude.”

The crew complied. The sheet passed unobstructed through the ship’s shields and hull, hovering inside the cabin.

It was as though the ship had enveloped it, yet the sheet’s position never changed.

”Hm...”

The technical team, Dr. Ratio, and the Genius Society members all fell into confusion.

”Dr. Ratio, this is...?...”

Oswaldo asked while directing operations remotely.

”I’m not certain. Perhaps we should consult someone even more capable.”

Dr. Ratio pondered for a long while. He felt fragments of thought forming, yet he could not grasp them fully.

An hour later.

Through connections arranged by the Genius Society and the Research Division, another girl’s projection appeared.

She had brown hair and violet eyes, wore a large purple witch hat adorned with floral decorations, and possessed a stunning appearance with an expressionless face.

Herta glanced at the situation.

”So? What exactly is here that warrants my special attention? My time is very valuable.”

”I have no intention of becoming entangled in your war. Don’t entertain any unrealistic ideas.”

She had no desire to involve herself in conflicts between other powers. Only after repeated requests, and upon hearing that this involved a peculiar creation from another world, had she agreed to project herself remotely to take a look.

”There.”

The technical team pointed, sending her the observational reports and inspection parameters from earlier.

”Oh? ...”

Herta’s holographic projection leaned slightly closer.

”It has no physical form? Is it encapsulated within a force field?”

”Hm... not conventional technology, nor related to the Imaginary. If it does not interact with the real plane, what is sealed within should be some kind of abstract conceptual entity...”

”A conceptual entity?”

Oswaldo and the technical staff repeated the term, unable to follow Herta’s train of thought.

”For example, space—or something else... hm, why would they do this?”

”The technology to cut and preserve space... very advanced. Very interesting.”

In an instant, Herta considered hundreds of possibilities. A strong interest in this unfamiliar creation arose within her.

”So what exactly does it do?”

Oswaldo was more concerned with practical matters.

”Its encapsulating force field is evaporating. We’ll know soon enough.”

”What?”

As they spoke, the gravitational wave signal from the sheet completely vanished. It shifted from semi-transparent to fully transparent.

Then, from hundreds of millions of kilometers away, the fleet heard a scream from the technical team.

”Ahhhh!!!—”

”The ship! Look over there—what’s happening?!”

”Don’t touch it—run! Aaahhh!!!—”

Whoosh—

After a flash of light, from a distance, the spacecraft looked like an ice cream cone smashed against scorching glass.

It melted into a spreading smear, fanning outward across a vast plane.

When the reconnaissance vessel exploded, Oswaldo even felt a trace of regret.

He assumed it had been an operational error that triggered some device. Fortunately, the destruction radius was not large—planets dozens of thousands of kilometers away were unaffected.

The Genius Society and Herta were observing remotely through holographic equipment. It made no difference to them.

Several dozen seconds later, the fleet watching from afar noticed something unusual.

The spacecraft had not exploded like a vessel struck by conventional kinetic or high-energy weapons. There was no reactor detonation, no annihilation.

It left behind not even a fragment of debris.

It was like ice cream slapped against glass.

First, the rear half of the ship dissolved. Then the entire craft lost control and collapsed toward that plane.

Several personnel attempted to flee in shuttles. They had only traveled a short distance before being dragged downward.

After emitting a scream and a violent burst of light, they flattened together with their ship—spread thin across the plane.

”What is that?”

Oswaldo and the fleet stared at the distant sight in confusion.

The human bodies and ships unfolded across the plane were displayed in a precise yet grotesque manner.

Every component of the vessel could be seen clearly—engines, reactors, weapon modules—all projected according to some rule.

But the projection rule bore no resemblance to engineering blueprints. Visually, it was almost impossible to reconstruct the original three-dimensional form from imagination alone.

The two-dimensional unfolding occurred across every scale.

All structures and details once hidden within three-dimensional configurations were laid bare upon the plane.

Every gear inside the starship engine. Every screw. Every missile loaded within the turrets. Every internal structure inside each missile—unfolded one by one.

The naked eye could perceive only limited scales. But if magnified through sensors, the image revealed nearly infinite detail.

Down to each molecule. Each atom.

Staring too long induced dizziness.

The curled human body within the cockpit was the same.

Muscles, bones, tendons, every organ—spread into a single image.

Anyone with knowledge of biology and anatomy could identify the flattened structure of the human body.

”What is that thing?!”

A wave of disturbance rippled through the fleet.

Herta’s projection reappeared aboard another vessel. In an extremely short span of time, she had performed thousands of calculations.

Her intuition told her this was something she had never seen before—something worthy of attention.

Lines of code and formulas raced before her eyes.

After a moment of contemplation, the girl reached a precise conclusion.

”It is a two-dimensional space, sealed within a force field.”

”Mm... I have seen some Curios that alter dimensionality. This is a new design concept—and a new method of application.”

”What are you talking about?!”

Oswaldo had no patience for her admiration.

”What does it do? How much destruction will it cause?”

”The civilization that created it sliced off a portion of two-dimensional space and packaged it inside a force field. Once the field dissipates, that two-dimensional space begins to make contact with the three-dimensional world.”

”Because our universe has a higher dimensional structure, three dimensions will inevitably collapse toward two—one dimension curling into the microscopic. At the same time, the three-dimensional space falling into two dimensions will further expand the area of the two-dimensional space.”

”Like dominoes, it will trigger a larger-scale collapse. There may be a limit, depending on whether the creators possess methods to constrain space. Or there may be none at all. In that case, the collapse will continue indefinitely.”

Herta suddenly felt intense curiosity toward the creator of the Dual-Vector Foil.

”What?!”

Oswaldo was horrified.

This information was simultaneously broadcast to other IPC supervisors stationed across different star regions.

They stared blankly at the two-dimensional region spreading outward, momentarily stunned.

At the beginning of the war, the Interastral Peace Corporation had suffered massive Photoid strikes. Ever since, every combat plan had revolved around Photoids and the thirty Emanators.

Whether relying on the Amber Lord’s Subspace Crystalline Barrier or gravitational interference devices, they had exhausted every technological possibility to defend against Photoid attacks.

But now the enemy had once again produced something utterly unfamiliar.

To make the three-dimensional world fall into two dimensions? To turn entire star systems—even entire galaxies—and everyone within them—into a painting?

It sounded like a cruel fairy tale.

Infinitely more elegant than brute-force Photoids.

Infinitely more cruel.

”Heavens...”

Oswaldo looked toward the sky.

He felt as though he had glimpsed a terrifying corner of the Starsea Empire’s true power.

Then he snapped out of his shock.

”Abandon this system! Full retreat!!”

Boom!!—

Across dozens of star systems, hundreds of thousands of fleets immediately turned about, engines flaring at maximum output as they fled in the opposite direction.

Planetary fortifications and ground forces were decisively abandoned. Starships accelerated to their limits, desperate to escape this land of death.

Whoosh—

The fleeing fleets streaked across the sky.

Beyond the portholes, the stars slid backward. The navigation systems indicated maximum acceleration had been reached.

Listening to the roar of the engines, the crews felt a brief flicker of relief.

But only minutes later, the navigator screamed:

”We’re not moving! The ship isn’t accelerating!”

”What nonsense are you talking about?!”

Oswaldo roared.

Using distant celestial bodies as reference points, the fleet appeared nailed in place within space itself.

Only the acceleration registered. Their position had not changed at all.

”When three dimensions collapse into two, the space in this region flows in the opposite direction. The acceleration is being canceled out.”

Herta rested her chin in her hand, observing through the holographic interface.

”What?!”

Oswaldo’s voice trembled.

”It’s like trying to row upstream at the crest of a waterfall. If the ship’s velocity cannot exceed the rate at which the two-dimensional space expands, collapse is inevitable.”

Herta continued her ocean of calculations.

Technicians aboard the ships hurriedly activated AI systems for complex computation.

”What is the escape velocity?! How much?!”

Oswaldo and supervisors from neighboring systems shouted simultaneously.

”...”

”We’ve run the calculations three times. They should be correct.”

The technical team stared at the results in disbelief.

”There is no escape velocity.”

”What?”

”What does that mean?”

”From the moment the two-dimensional space was released, its collapse speed has been increasing exponentially. In a short time, it will reach light speed—then surpass it—becoming a value beyond comprehension.”

”The creators used dimensional technology to vastly enhance the expansion speed of the two-dimensional space. Once fully unfolded, the dimensional collapse becomes a form of superluminal action at a distance.”

”The principle is identical to the Starsea Empire fleet’s faster-than-light weapons. From one star system to another in less than a second—until the collapse reaches the limit preset by its creators.”

”Furthermore, at the moment collapse began, this region of space was artificially disturbed. Even with jump engines, escape is extremely difficult.”

The personnel performing the calculations stared at the data, speechless.

”My God... this is... technology of the divine.”

”!!!”

Panic exploded throughout the fleet.

An escape velocity approaching infinity meant no escape at all.

The moment the Dual-Vector Foil descended upon this region, the fate of dimensional collapse had already been sealed.

Unless they could escape its range in a very short time.

But how large was that range?

No one knew.

Even so, every ship activated its engines at maximum power, racing toward the void.

Boom—Boom!!—

No matter how the thrusters overloaded, the ships were like canoes rowing upstream—inevitably dragged backward.

The first to fall into two dimensions were the orbital space cities.

Like great ships with ruptured hulls, they sank into the two-dimensional plane.

Everything that made contact with the plane was instantly flattened.

Entire architectural complexes were sliced cleanly by the rising plane. Their two-dimensional forms spread outward.

The vibrant colors and complex structures of the cities surged across the surface like lightning.

Corporate armed personnel without aircraft, unable to escape, began to fall into the plane as well.

Like droplets of ink landing on water, they spread instantly—revealing distinct two-dimensional human forms.

Some still gripped weapons, firing futilely into the distance.

Others attempted to flee, only to be swept into the plane.

Many soldiers and vehicles were flattened together, their poses preserved mid-operation—hands on controls, bodies inside shuttles.

Sensors scanning from afar displayed a panoramic image of the two-dimensional space city.

It was orders of magnitude larger than its three-dimensional counterpart.

Yet it was a dead city.

More precisely—it was a 1:1 blueprint.

Upon that colossal drawing were recorded every detail of the city.

Each screw.

Each fiber.

Each bacterium.

Hum—

Next to fall were the planets on the opposite side of the system.

Like snowballs melting upon glass, they dissolved into vast circular paintings.

The outermost layer was the pale blue atmosphere—along with ships and shuttles flattened within it.

Next came mid-layer structures and stationed soldiers, laid out in grotesque arrangements across the surface.

Even the dense heavy-element core did not escape.

It became the center of the colossal ring-shaped painting.

The spread of the two-dimensional space accelerated further—catching up in an instant with the fleeing fleets.

Countless ships overloaded their engines to the extreme, yet were dragged backward together with the entire region of space.

Boom!—

The rearmost vessels were overtaken first.

Explosions erupted one after another as they became part of the grand painting of destruction.

Each squadron crushed emitted a grinding, creaking sound.

Turning back, one could see the two-dimensional plane advancing, crushing everything in its path.

Some ships fired desperately at it.

But even the missiles and energy weapons they launched were printed upon the colossal image.

The missile exhaust plumes and thruster flames were perfectly preserved—absolute accuracy, absolute precision.

Yet within two dimensions, they could no longer advance even a single centimeter.

Three-dimensional collapse into two dimensions was absolute annihilation.

Organic or inorganic—it made no difference.

Unless one transformed oneself into a two-dimensional being.

The terror surpassed even being killed instantly by a Photoid.

One could only watch helplessly as one became a painting.

”Aaaahhh!!—”

As the starships were dragged inch by inch toward the abyss, Oswaldo and the soldiers screamed into the communications network:

”We surrender! We surrender!!”

”Stop!!—”

They did not know whether the enemy could hear them.

They simply clutched at their final straw, attempting by every possible means to contact the Starsea Empire and neighboring civilizations.

Bzz—

Observer’s communication connected.

The little girl tilted her head and smiled.

”Too late.”

”I’ll preserve your posture and build a giant interstellar museum here.”

”Everyone in this universe will see what you look like—and remember the foolish civilization that once attempted to challenge the Starsea Empire.”