Crossover Shipgirls: Building a Dimensional Empire from Scratch

Crack—

Across Jumu, and within more than a dozen surrounding star systems.

Accompanied by the explosions of starships and the sound of shattering glass, two-dimensional space tilted and swept across everything.

Within each system, hundreds of thousands of fleets were compressed like clay by an overwhelming force, flattened into paintings without thickness.

Beginning from the rear of the formations, more than ten thousand starships were crushed by the two-dimensional plane within mere seconds.

”Aaaahhh—”

As they fled in blind panic, unprecedented chaos erupted throughout the retreating fleets. Watching their comrades behind them fall continuously into the two-dimensional space, no one cared about commands anymore.

Engines were pushed into frenzied overload. To clear a path, some ships even fired recklessly at allied vessels blocking their way.

Yet as the two-dimensional plane continued to unfold, the rate of descent only accelerated.

The surrounding space seemed to form a massive vortex. Everything within it was inevitably dragged inward.

Oswaldo’s flagship outperformed the other warships in the fleet. At maximum output, it broke ahead of the formation and flew at the very front.

”Forward!! All engines to maximum overload—get out of here!!!”

Crackle—

Even so, he survived only 0.01 seconds longer than the ordinary soldiers behind him.

The luxurious, magnificent starship was swallowed instantly by the two-dimensional plane, Oswaldo’s final motion frozen upon it.

He stood at the very front of the main control room, desperately urging the crew to accelerate. His right hand remained suspended midair, terror frozen across his face.

Around him were equally panicked corporate employees, captured in various postures—imprinted with absolute precision within the two-dimensional space.

If one observed closely, every detail inside their bodies could be seen—each bone, every vein and tendon, every single cell.

The entire fleet was arranged in neat formation across a single sheet.

The unfolded two-dimensional image was far larger than its original three-dimensional structure. From a distance, it resembled an enormous painting stretching across the sky, spanning several light-years in diameter.

Standing upon a distant Siren warship, one could see it clearly with the naked eye.

The entire Interastral Peace Corporation fleet, together with the warships they had hired and gathered, had been printed upon the canvas.

Within the two-dimensional space, the outlines of the starships were still faintly discernible—along with the dozens, hundreds, or even thousands of crew members contained within them.

There were sixteen such colossal paintings in total—the main fleets they had assembled to intercept the Photoids and the thirty Emanators of the Starsea Empire.

”Magnificent, isn’t it?”

The Siren girl seemed quite satisfied with the result and took a sip of juice.

”Ah...”

The group she had dragged over to observe opened their mouths, unable to speak.

Was this how space wars were fought?

Feixiao felt that the two sides’ understanding of warfare existed on completely different levels.

At the outset of the war, the Starsea Empire had cleared the way with Photoids, massively destroying enemy star systems and critical nodes.

The Interastral Peace Corporation had gathered the vast majority of its forces, relying on the Amber Lord’s miracle in an attempt to intercept the Starsea Empire fleet.

And what had they encountered?

A flimsy sheet of paper. A two-dimensional space.

Without even seeing the enemy fleet, they and their entire star systems had been printed into paintings in the blink of an eye.

Even exhausting their imagination, they could not comprehend how interstellar warfare could escalate to such a level.

Sushang recalled how she had just poked the Dual-Vector Foil earlier. Panic immediately set in.

”Aaaahhh—”

”Am I going to turn into a painting too?!”

Thud—

Observer knocked her lightly on the head.

”I thought you were pretty brave? Now you know fear?”

”How... did you develop something like this?”

Feixiao asked.

”Manipulating fundamental laws is something any civilization must eventually do once its technological level reaches a certain stage.”

”Didn’t I ask you earlier? If you want to kill three-dimensional life quickly, efficiently, and thoroughly, the answer is simple—remove one of their dimensions.”

”It’s far more convenient than conventional weapons or all sorts of messy magic. Just toss one piece over, and the world becomes quiet.”

As she spoke, the little girl’s tentacle-like ship rigging produced another slice of Dual-Vector Foil and waved it in front of them.

”Aaaahhh!!—”

Guinaifen and Sushang’s nerves visibly twitched.

”Could you please put that away first? It looks terrifying!!—”

”...May this humble one ask—can anyone live within two-dimensional space?”

Having recovered from her shock, Tingyun asked curiously.

”Of course not. A two-dimensional world has no thickness. How could anyone live inside a painting without thickness?”

Observer shook her head.

”However... in the Three-Body universe, we know some civilizations have already begun preparing for two-dimensionalization. Through technological means, they plan to transform themselves into two-dimensional beings to welcome the future dimensional reduction of the entire universe.”

”The Dual-Vector Foil was obtained from them. But before we mastered range constraints for two-dimensional space, we never used it.”

”Oh...”

Tingyun felt her head ache slightly. No matter how she thought about it, she could not imagine what life in a two-dimensional world would be like.

Everything would be reduced to points and lines. If one drew a circle on paper, a three-dimensional being could see the entire circle, but a two-dimensional being would see only an arc.

She wanted to ask more, but Observer pointed toward the starry sky outside.

”It’s not over yet. The most spectacular part is coming. Bring me some popcorn.”

She instructed the Angeloids to fetch some soda and drinks.

”What?”

Everyone froze.

”That girl named Herta was correct earlier. The escape velocity of the Dual-Vector Foil is infinite.”

”Using dimensional technology, we’ve vastly enhanced its diffusion speed. Otherwise, it would be useless against light-speed ships and interstellar civilizations.”

”Once the two-dimensional space fully unfolds, dimensionalization becomes a form of superluminal action at a distance. So... you’re about to see something extremely cool.”

The little girl settled into the bridge seat, casually opened a holographic interface, and began carefully recording the first real combat report of the improved Dual-Vector Foil.

After hundreds of thousands of ships had been two-dimensionalized, the two-dimensional region expanded to cover most of the star systems. Soon, it exceeded the original diffusion speed of the foil.

It began swallowing the surrounding three-dimensional space at speeds surpassing light.

Just as a Tachyon Lance could traverse several light-years within a nanosecond to strike its target, once the two-dimensional space reached a certain critical point, its speed became nearly infinite.

”The stars!!”

Sushang cried out.

In an instant, the sky changed.

The distant sun was swallowed by the two-dimensional plane. Upon the flat surface, it expanded rapidly into a circle, forming a vast sea of fire.

A star collapsing into two dimensions was far more spectacular than being shattered by a Photoid. The moment it touched the plane, it burst into brilliant radiance, slowly sinking downward.

The two-dimensional sun could roughly be divided into three ring layers.

At the center was a blinding region of light where details could not be seen—corresponding to the fusion core of the three-dimensional sun.

Beyond it lay a vast ring representing the radiation zone—a boiling two-dimensional ocean. Within the blazing red glow, countless cell-like microstructures formed, vanished, split, and recombined at astonishing speed. From a local perspective, it appeared chaotic and restless.

The outermost layer was the convective zone. Like its three-dimensional counterpart, this region transferred heat to two-dimensional space through stellar convection. It displayed a remarkably ordered structure, with neatly arranged circular convection loops in motion.

The light of the two-dimensional sun radiated across the plane. The space fleets that had just fallen into the two-dimensional realm were coated in a layer of golden brilliance.

Even though life had completely vanished there, the two-dimensional world experienced a sunrise.

At the same time, within each painting, stars and countless celestial bodies were swallowed. Hundreds and thousands of light-years of three-dimensional space were drawn inward.

The initial targets of the Dual-Vector Foil had been more than a dozen isolated star systems.

What had begun with the destruction of only a few star systems soon escalated into the annihilation of millions. As the two-dimensional space spread beyond the systems, the smaller regions gradually merged together, forming a death zone hundreds of light-years in diameter.

Stars were devoured at visible speed by the colossal two-dimensional region. After releasing immense energy, they became two-dimensional fireballs.

Two-dimensional stars were several orders of magnitude larger than three-dimensional ones—large enough to be observed clearly at astronomical scales.

Looking up, one side of the sky had been consumed by two-dimensional space. It appeared abruptly against the cosmic background, utterly devoid of depth—like a gigantic painting hung in the night sky.

The starry sky had become two-dimensional.

Observer took out an exquisitely decorated painting and held it before her, admiring it for a moment. Tingyun recognized it—it was a collectible brought back from another Earth.

Van Gogh’s Starry Night.

”They’re both paintings. Quite similar, don’t you think?”

...

Once the Dual-Vector Foil passed its critical point, its expansion speed became astonishingly fast—so fast that employees in nearby starfields were swept in before they even received the news.

Only when the boundary of the two-dimensional world had extended across nearly one fifth of the galaxy—when that vast expanse had become part of the painting of destruction—did the collapse finally cease.

Looking up, one could see a colossal two-dimensional painting suspended among the stars overhead.

Upon it, arranged according to unique geometric rules, were the former three-dimensional star systems—along with the Interastral Peace Corporation’s countless planets and fleets.

Zooming in with sensors revealed every detail of the giant image.

Every starship that had gone to war. Every single soldier of the Interastral Peace Corporation.

They now floated silently in space, fixed within the two-dimensional world, displaying the outcome of this war to every civilization in the universe.

At the same time.

On the Xianzhou ships, aboard the Herta Space Station, and within advanced interstellar civilizations across countless galaxies, all witnessed that astronomical spectacle.

Not long ago, through Interastral Peace broadcasts, they had learned that the war between the Starsea Empire and the Interastral Peace Corporation had entered a white-hot stage.

Many had speculated that a prolonged interstellar war was imminent.

Instead, the anticipated large-scale fleet battle never occurred. The war ended countless times faster than anyone had imagined.

Millions of starships and star systems, along with countless corporate soldiers and employees on planets, aboard space fortresses, and within trade ports... met their end in a horrifying fashion.

They were reduced by one dimension—turned into a giant painting hung in the cosmos by the Starsea Empire.

In ancient eras of cold steel, victors once built pyramids of skulls to flaunt their martial prowess and intimidate their enemies.

Dimensional reduction was far more elegant—and far more shocking.

That empire from another world had announced its power and technological supremacy to all civilizations in this form.

”Mm... three-dimensional beings cannot directly see objects within two-dimensional space. What you’re seeing now is merely the energy released when three dimensions collapse into two.”

”Given the scale of celestial bodies, this painting should last quite a long time. We might as well build a memorial here.”

Observer began making arrangements, contacting the Northern Parliament Fleet.

”That way everyone can come visit in the future. Not many people in this universe have witnessed dimensional reduction, right? It’s a specialty of the Three-Body universe.”

”Ah!”

The Xianzhou group, who had barely recovered from the earlier shock of seeing the Dual-Vector Foil, were once again overwhelmed by something even more astonishing.

Only after Observer poked them a few times did they snap out of it.

”A memorial...?”

Yukong stared at the colossal painting in the sky for a long moment.

That two-dimensional region was, in essence, the graveyard of the Interastral Peace Corporation fleet.

With numerous star systems lost, the majority of its fleets and high-ranking personnel two-dimensionalized, the IPC had no strength left to continue the war.

Rather than a memorial, it was more like a warning to other civilizations.

Before making trouble, think about the Interastral Peace Corporation’s fate—and ask yourself whether you can withstand Photoids and the Dual-Vector Foil.

”Uh...”

Feixiao paused, then voiced an unusual thought.

”Could you sell us a few Dual-Vector Foils? They’d be perfect for suppressing the Abominations of Abundance.”

Pfft—

The little girl nearly burst out laughing.

”Sorry. Not for sale. Even within the Starsea Empire, the use of the Dual-Vector Foil is under strict regulation.”

”Although its strike range is now controllable, any star region reduced to two dimensions is effectively erased permanently. It’s rather wasteful—and dangerous for passing starships.”

”If you’re dealing with Abominations of Abundance, aren’t your Gundams sufficient?”

”True.”

Feixiao thought it over.

Against the Abundance followers, weapons of this scale were unnecessary. A single mistake and even the Xianzhou would be finished.

”Eek...”

Tingyun trembled faintly at the side. Fortunately, she had behaved appropriately during her diplomatic mission to the Starsea Empire and maintained good relations. Otherwise, who knew what disaster might have followed.

”Don’t be scared. The Commander quite likes you. He even told us to look after you~”

Observer patted her.

”Ah? Um—thank you for the Sacrosanct’s favor?!”

Tingyun wagged her tail, flustered and overwhelmed.

”All that’s left now is cleanup work.”

The Siren girl yawned.

A considerable portion of the Interastral Peace Corporation’s upper management and the vast majority of its fleets had been struck by dimensional reduction.

As for the remaining scattered forces—after witnessing the Starsea Empire unveil both Photoids and the Dual-Vector Foil in succession—it was hard to imagine how much fighting spirit or combat capability they still possessed.

Anyone with basic intelligence could understand the immense technological and military gap between the two sides.

”Well then—do you want to return to the Xianzhou, or wander around here a bit?”

...

Hum—

Elsewhere.

The Northern Parliament Fleet encountered almost no resistance along the way. Conducting consecutive jumps between star systems, it headed straight toward Pier Point.

After several department directors and the main fleets were reduced to two dimensions, the remaining resistors either fled or scattered.

Mercenaries cared little for reputation or contracts once signed with the IPC. They turned tail immediately. No amount of credits would convince them to remain in this star region.

Judging by the situation, the IPC was finished. Whether credits would even hold value in the future was uncertain.

Rank-and-file soldiers likewise commandeered small ships or fled alongside convoys.

Meanwhile, as one of the industries least affected by the war, Interastral Peace News and numerous media outlets continued their work diligently.

”Welcome to tonight’s Interastral Peace Evening News. First, the headlines...”

”The Starsea Empire has deployed a weapon of mass destruction against the Interastral Peace Corporation. Twenty-three percent of the IPC’s core star regions have been subjected to two-dimensional strikes. The number of lost star systems is...”

Even the anchor froze momentarily upon seeing the script.

He questioned whether he had misread the number of destroyed systems and confirmed it repeatedly with the director.

”This station reminds all trade guilds and travelers: do not approach the region stretching from Jumu to Nachitov. There remains a risk of dimensional collapse.”

”The Interastral Peace Corporation strongly condemns the Starsea Empire’s atrocities. This is a blatant trampling of universal morality...”

”We call upon all partners of the Interastral Peace Corporation to unite and resist these atrocities...”

With its main fleets annihilated, the IPC no longer had the capacity to proclaim that it would drive the invaders from its homeland.

All it could do was issue moral denunciations.

The broadcast triggered immediate upheaval across the cosmos.

Many civilizations had been curious about the astronomical spectacle. After verifying through multiple sources, they received the answer:

The Interastral Peace Corporation was in total collapse.

As for the IPC’s appeal for allies and partners to join the war—other civilizations glanced at Oswaldo and his fleet hanging within the painting and could only express support in every way except actual assistance.

Hum—

Midway through the news broadcast, a tremor of space echoed from afar.

Blue-gray warships tore through the void, appearing within the Pier Point star system.

”Huh?”

Boom!!—

A spear of light slashed across the starry sky.

The pitiful firepower of orbital defense platforms and military fortresses was crushed instantly. The few remaining military vessels were reduced to annihilated states.

Within a single minute, the nanite warships destroyed all military forces within the system.

On the planet below, everyone looked up at the colossal vessel slowly hovering overhead, their hearts shaken.

Since the founding of the Interastral Peace Corporation, this was the first time an enemy had struck its headquarters.

Chaos erupted across the planet. Some hurriedly piloted ships to escape. Others hid within shelters. A few even raised the banner of the Starsea Empire, preparing to welcome their new rulers.

”You’re condemning my morality?”

Grey expressed strong dissatisfaction toward the Interastral Peace Corporation.

She scanned Pier Point. As corporate headquarters, only officials ranked P36 or higher could reside there—the IPC’s managerial elite.

The planet was well developed. Even by the standards of the Starsea Empire, it was considered prosperous.

”Hiss—”

The onlookers stared uncertainly at the nanite warships.

”We surrender! We request negotiations!”

”Unconditional surrender!!”

The remaining high-ranking executives initiated communication with Grey, making the same choice as the department heads before them.

The war had reached a point where there was nothing left to fight for. The Interastral Peace Corporation had lost all ability to resist.

The Amber Lord had not responded to the IPC’s pleas. They appeared uninterested in such struggles.

”Now? At this very moment? Are you joking?”

The nanobots snorted.

”Since you were just attacking my moral standards, I’m going to do something truly immoral right now. Care to guess what it is?”