Crossover Shipgirls: Building a Dimensional Empire from Scratch

Crack—

The starship entered planetary orbit.

Honkai No. 1 Space Station continued to revolve slowly around Earth.

Ever since the Honkai problem had been resolved, this place had existed as a subsidiary universe of the Starsea Empire.

Under the administration of Sophon and the Angeloids.

Setsuna glanced down briefly.

The unrest caused by conquering the world earlier had been completely pacified.

The traces of Schicksal had been entirely erased from Earth, and so-called ”illegal organizations” such as World Serpent had been abolished as well.

Now, the entire world had only one highest administrative authority: Sophon.

Led by Sophon, the Angeloids had established a brand-new governing system.

”Oh...”

Cecilia leaned over and took a look.

Familiar, yet unfamiliar.

Sophon’s efficiency was astonishing. The cities had already been reorganized into forms she no longer recognized.

All kinds of anti-gravity structures extended from the ground into the sky—futuristic and advanced.

Judging from the orderly state of the cities below, this world was living in remarkable peace.

”Um... don’t the people of Earth have any objections? About being conquered by the Starsea Empire and becoming some kind of vassal state in the future?...”

Shigure Kira asked curiously.

Without realizing it, she had already placed herself on the side of the Starsea Empire, referring to the native inhabitants of Honkai as ”people of Earth.”

”Suppose an alien civilization conquered Earth and declared that they would use more advanced technology to increase productivity and develop outer space.”

”They effortlessly cured every terminal illness on Earth. A dark matter reactor brought forth endless energy. At the same time, they destroyed all privileged classes and declared that everyone would be ruled equally.”

”Your food, clothing, housing, transportation, and medical care all improved by several levels. The only requirement was that the Empire would take a portion of the developed cosmic resources and that you maintain respect toward the suzerain state.”

Grey crossed her arms and looked at Shigure Kira.

”If it were you, what would you do?”

”Uh... joyfully welcome our alien overlords, put up a great statue of the Commander, and worship it every day?”

Shigure Kira scratched her head.

She was amazed by the improvements brought about by technological superiority. It was like traveling back to ancient times and rallying countless followers with nothing more than plain porridge and pickled vegetables.

Just a tiny scrap leaking through the fingers of a super civilization was enough for the natives to enjoy without end.

Beep—

Sophon’s communication connected at just the right moment, giving Setsuna a brief report on the management of the Honkai world.

”The integration of Earth’s administrative system has been fully completed. We have surveyed the resources within the solar system and expect to begin development within one month.”

”The solar system of this world differs from others. It is larger in scale, and its outer edges are blocked by imaginary energy tides. Conventional spacecraft cannot break through the star system and must rely on jump engines to reach farther regions.”

On the star map, the latest exploration results of nearby star systems were displayed.

”In addition, whether other civilizations exist within this universe remains to be confirmed. We request the deployment of additional fleets for further reconnaissance.”

Sophon requested.

”Approved.”

Setsuna made a few gestures, dispatching the Angeloids to mobilize more conventional fleets.

”There are alien civilizations here? Seriously? Natives or interstellar civilizations?”

Humanity’s Evil immediately grew interested.

”Should we send the Eternal Snowfall to bump into them? Or have the Outer God Legion go fight an Aeon?”

”...”

”We’ll talk after we finish dealing with the Previous Era.”

Bonk—

Setsuna knocked her on the head again.

After arranging and reviewing the work here, the starship immediately set sail.

Crack—

The Eternal Snowfall unfolded into hyperdimensional mode, switching from three-dimensional spatial coordinates to spacetime coordinates.

From the planet’s surface, only the projection of the Eternal Snowfall in the three-dimensional world could be seen. Its volume was stretched countless times, as if it obscured half the starry sky.

[Hyperdimensional expansion complete]

[Spacetime coordinates confirmed]

Vmmmm...

As the AI prompt sounded, everyone’s perspective was once again pulled into higher-dimensional space, overlooking everything in the world.

”The Previous Era is simpler than the Current Era. It doesn’t involve multiple temporal jumps. We just go back, pull the people out, and resolve the Honkai problem.”

Setsuna said.

”It shouldn’t take long.”

Whoosh—

The instant the engine activated,

Everyone felt a brief moment of disorientation. When they looked down again, their expressions changed drastically.

”Time is flowing backward?!”

Earth’s rotation reversed from east-to-west, and its revolution followed suit.

Unlike when traveling to the future—where the world accelerated forward—every person’s movements on the planet began to rewind. The entire world became like a film played in reverse.

As the speed increased, the numbers on the starship’s temporal coordinate axis grew smaller and smaller.

First it retreated to the feudal era of the Middle Ages, then to the tribal age thousands of years before the Common Era, then to the primitive age before the birth of humanity...

The span of time crossed grew ever greater, and Earth’s reverse revolution accelerated until it formed a blue streak of light across the starry sky.

[Current time coordinate: 1322 CE... 562 CE... 1 CE...]

[2000 BCE... 6000 BCE... 18,000 BCE...]

Finally.

When the temporal coordinate stopped at over fifty thousand years before the Common Era.

Crack—

[Confirmed. Target spacetime reached: Previous Era]

The starship exited its hyperdimensional state and contracted once more into the three-dimensional form of the Juggernaut, slowly descending from higher-dimensional space.

”Ah...”

After crossing fifty thousand years of time, everyone felt an intense sense of unreality.

Earth was not the imagined ruin. Instead, it possessed a remarkably prosperous civilization.

Skyscrapers stood tall, and the streets bustled with crowds.

The architectural style differed slightly from that of the Current Era. In terms of technological level alone, it was even somewhat more advanced.

”Ah...”

”So this is where the predecessors of the last era lived...”

Cecilia, Tesla, and the others felt dazed.

Fu Hua and Griseo stared at the familiar scenery below, stunned for quite a while.

They were back.

The Previous Era.

The world that had exhausted every possible means to fight against Honkai, only to fall short at the last moment and watch the Herrscher of Finality destroy everything.

The despair of that final battle still lingered vividly in memory.

”Commander...”

Griseo instinctively squeezed Setsuna’s hand.

Thankfully, now she had companions from the future by her side.

”Deploy Sophon. Monitor the world.”

As per routine, the Eternal Snowfall launched a Sophon toward Earth.

It hovered above the North Pole. After unfolding, it transmitted every minute detail of the planet’s information back to the starship.

Swish—

At the same time, it projected before Setsuna a list of companions to be recruited from the Previous Era. Their detailed information and exact locations were clearly marked.

”~Oh? This point in time is interesting.”

At his signal, the starship slowly descended from the sky.

...

On Earth, inside a certain base.

The facility stood apart from the city, existing in a state that was half-confidential, half-public. The emblem of the Fire Moth was printed on the walls, and staff members moved back and forth inside.

Fire Moth—the anti-Honkai organization established by the United Nations of the Previous Era to avert the crisis of civilization’s extinction.

Inside the base laboratory.

A girl with long green wavy hair cascading over her shoulders and a black hair ornament was handling test tubes while operating a holographic interface.

She was completely absorbed in her research.

Beside her stood another girl with long pink hair, her appearance adorable yet tinged with a hint of playfulness, doing her best to persuade the scientist before her.

”Mobius, your experimental direction isn’t appropriate. Even for the sake of evolution, humans can’t be modified into Herrscher-like beings. If that happens...”

”No.”

Mobius paid her no mind.

”By my hand, humanity shall ascend to godhood.”

”If this method can defeat Honkai and open a new path of evolution, there is no reason to abandon it.”

As one of the most cutting-edge scholars in Earth’s scientific field, Mobius had naturally joined Fire Moth to participate in the fight against Honkai.

Her other objective was to explore the destination of human evolution. Coincidentally, merging with Honkai energy and becoming a being akin to a Herrscher was an excellent direction.

Herrschers possessed far greater adaptability to Honkai energy than humans—powerful and mysterious. If their secrets could be unraveled, humanity might evolve into a stronger species.

”...”

Elysia simply could not persuade Mobius.

She sighed, about to say something more.

Suddenly.

A faint yet strange sensation drifted over.

Honkai energy.

Extremely subtle, fleeting in an instant.

No one else inside the Fire Moth base noticed it. Only Elysia, as a Herrscher herself, keenly sensed it. The power felt familiar.

”A Herrscher?! ...No, it’s stronger—and more complex...”

She frowned slightly.

”...This feeling... it’s like... the source of the Herrschers? Ah?!...”

Was that my imagination?

Elysia closed her eyes, momentarily dazed.

She glanced out the window with a puzzled expression.

That trace of dissipating Honkai energy had vanished in an instant—strange and powerful.

”Could it be that a new Herrscher has descended? Did you detect anything?”

She asked Mobius.

”What are you talking about?”

Mobius replied flatly, sweeping her gaze across the holographic interface without even pausing the movements of her hands.

No alarms. Everything was normal.

The Second Honkai Eruption had only recently passed. How could Herrschers appear one after another?

”Maybe I sensed it wrong?”

”More importantly... hmm? This quantum mechanics paper was published by a student?”

Mobius’s attention was quickly drawn elsewhere.

Not long ago, she had noticed a publicly published thesis. Its subject matter was advanced, its viewpoints cutting-edge—she had initially assumed it was written by a senior authority in the field.

Upon closer inspection, she discovered the author was still a student.

”Interesting... send me her information.”

Whoosh—

The detailed file was transmitted. Mobius glanced over it, her expression growing more intrigued.

”A student from Chiba Academy? Named Mei?”

”Mm... I’ll go speak with her. She’s definitely a genius.”

Chiba Academy was located in Nagazora City in the Far East, some distance from the base here.

Just as Mobius tapped at the holographic interface, planning her itinerary—

Vmmmm...

Beep—beep—beep—

A shrill air-raid siren suddenly rang out, both within the base and in the nearby city.

Outside the laboratory, personnel rushed back and forth. Footsteps grew increasingly urgent as the facility entered a combat-ready state.

”What’s going on? Another Honkai outbreak?!”

Elysia and Mobius were both startled.

Then, from the staff, they received an utterly incomprehensible answer.

”An alien civilization’s fleet has descended over Nagazora City!!!”

”What?”

”Aliens? Nagazora City?!”

...

”It seems we arrived quite early.”

A Titan-class vessel from the Eternal Snowfall, accompanied by the expeditionary fleet, broke through the clouds and slowly descended from high altitude.

Through temporal positioning and observation of key targets, Setsuna quickly confirmed the exact timeline of his arrival in the Previous Era:

Between the Second and Third Honkai Eruptions.

At this point, Fire Moth had only recently been established as the official United Nations organization to combat Honkai.

Among the Thirteen Flame-Chasers, only Elysia, Mobius, and Vill-V had formally joined Fire Moth.

Not even the Divine Keys had been forged yet. The Project MANTIS had not been proposed. It was extremely early.

Humanity was still attempting to rely purely on technology to fight Honkai, completely ignorant of how Herrschers were born or what Honkai energy truly was.

Vill-V was even still confined on P-21 Island, watching monkeys bare their teeth.

”Mm... at this time, I should still be studying in Sapphire City?”

Fu Hua said uncertainly.

”Isn’t this a bit too early?!”

”No. It’s just right.”

Setsuna shook his head.

”To change the tragedy of the Previous Era, we naturally have to start from the beginning.”

”From the moment we arrived here, the fate of the Previous Era’s Honkai world has been completely altered.”

He gazed at the bustling city below.

”Sapphire City will not be destroyed. The Mu Continent will not be obliterated by the Ninth Herrscher. The tragedy of Binding will never occur... As for the Herrscher of Finality—heh, I’ll make proper arrangements for her.”

”In the past, the present, and the future, all Honkai will be personally eradicated by me.”

Beep—

A message was swiftly broadcast to the entire world by Sophon.

Within Fire Moth’s base, at the United Nations headquarters, before the leaders of every nation, Sophon projected a holographic interface.

In a calm yet unquestionable tone, she announced the arrival of the Starsea Empire:

”Please remain calm. This is the expeditionary fleet of the Starsea Empire.”

”We come from another world. We will completely eliminate the threat of Honkai, allowing humanity to live in peace upon Earth.”

”The Empire’s fleet bears no hostility toward you. All that is required is compliance with the Commander’s directives and arrangements.”

”...”

The communication was brief, simply declaring their purpose and intent.

Conquering a civilization that existed fifty thousand years in the past held no meaning. It was enough to stabilize them, have them follow his command, and prevent internal strife.

The primary purpose of coming to the Previous Era was to retrieve people.

”Eh?!”

The upper echelons of the United Nations, national leaders, and Fire Moth members were thrown into chaos.

What the hell?

Aliens came to help us eliminate Honkai?! Seriously?!

Rumors spread instantly through the city. Noise and panic erupted.

Every news broadcast cut in with urgent reports of this monumental development.

Government officials deliberated, summoning think tanks to determine the origin of this unfamiliar civilization.

”Mm?”

Elysia and Mobius received the message as well.

Sitting in her chair, Elysia twirled a strand of her pink hair around her finger, pondering its contents.

”A civilization from another world? How interesting~”

Unlike the panicked masses, her curiosity overrode everything else.

”Are they humans? Or some other species? Oh—don’t tell me they have three eyes and two heads, with tentacles and things like that? I wouldn’t like that at all...”

As she spoke, Elysia examined Sophon.

The projected figure appeared cold and composed, with refined features. By human standards, she was undoubtedly beautiful.

”Could you chat with me a little more, Miss Hologram? How should I address you?”

”...”

It was the first time Sophon had encountered someone trying to make small talk with her.

”I am the artificial intelligence of the Eternal Snowfall. Miss Elysia, the Commander will send someone to receive you shortly.”

...

Above Nagazora City.

The crowd stared in terror at the majestic fleet overhead.

”Go. Bring them back first.”

At Setsuna’s signal, the starship slowly descended.

”Ah...”

Griseo pressed herself against the viewport, searching for familiar figures.

Unfortunately, since it was still so early, most of them had not yet joined Fire Moth.

”Mother Aponia...”

”She should still be living on Dusk Street right now. Don’t worry—we’ll go find her soon.”

Setsuna gently rubbed Griseo’s head.

”Mm...”

Inside a small restaurant near Chiba Academy.

A young white-haired boy was eating noodles, two pieces of luggage placed beside him.

Today was his first day transferring to Chiba Academy.

As for what he would encounter at his new school—and what kind of future life awaited him—Kevin felt full of anticipation.

Concepts like Honkai and Herrschers were still far too distant for an ordinary student.

Vmmmm—

Suddenly.

The sun overhead was blocked by a massive shadow.

Customers looked up to see the silver hull of a warship. The angular turrets beneath it were enough to make one’s scalp tingle.

They scattered in panic.

”Eh?”

Kevin froze, his chopsticks suspended mid-slurp.

The future leader of Fire Moth, the boss of the Current Era—at this moment, he was merely a spirited young man.

Confronted with an interstellar warship as a native of a pre-spacefaring civilization, the overwhelming shock left his brain temporarily frozen.

Whoosh—

Grey descended with several Angeloids.

She glanced at the bewildered Kevin and grinned.

”Well, look who’s here.”

”But your future doesn’t concern you anymore. Go home and finish your noodles in peace.”

The nanorobot tossed two bills onto the table.

”!!!”

Kevin looked at Grey, then at the starship hovering overhead.

It seemed his classes at Chiba Academy were unlikely to continue.

He wanted to ask something more, but the other party clearly had no intention of answering.

He stood up, slung his backpack over his shoulder, grabbed his bowl—and ran.