Crossover Shipgirls: Building a Dimensional Empire from Scratch

Clack—

”Here, this will be your room.”

An Angeloid guided Cecilia, Cheng Lixue, and the others into the starship’s residential sector.

Contrary to their expectation of cramped, utilitarian quarters like those on typical spacecraft, they discovered that this vessel’s immense size allowed for surprisingly spacious accommodations.

Each person even had a duplex suite—comparable to a small villa back on Earth.

”Whoa...”

Cecilia looked up in awe. Thanks to the holographic dome overhead, the starry expanse was visible directly above. Beyond the window stretched a boundless sea of starlight.

Living here offered a breathtaking sense of openness—none of the claustrophobic confinement typical of conventional spacecraft.

Cecilia had seen Schicksal’s ships before. To minimize space usage and propulsion costs, crew quarters were always cramped and sealed.

By comparison, the Starsea Empire’s warship felt more like a luxury hotel.

Even the furniture and decor—high-tech, elegant, and entirely unfamiliar—felt almost surreal.

Cheng Lixue and Cecilia remained relatively reserved, while Patricia eagerly tapped at the walls, playing with the holographic interface.

”Hey, this is just like a sci-fi movie!”

”No, even better. I swear this is way more advanced than anything in the movies! Are they really from the 15th century? Feels like they’re the future people, not us...”

Technically speaking, the Starsea Empire and Kallen existed on the same historical timeline, while the current civilization was the far future.

But after seeing this starship—this so-called vessel from five centuries ago—Cecilia couldn’t help but feel like the primitive one.

Especially after learning that the Starsea Empire had reached Earth long ago, back when Shenzhou’s ancestors were still discovering fire—she was completely stunned.

”Ugh... have we still not caught up with the ancients after thousands of years?”

”Impossible,” Fu Hua interjected, shaking her head.

”The influence of Honkai prevents Earth from mastering technology beyond its time. I’ve tested this myself.”

”I don’t know what the upper technological limit is under Honkai’s constraint, but it can’t be too high.”

”If Honkai isn’t permanently eradicated, this planet will eventually repeat the downfall of the Previous Era.”

”Oh...”

Cecilia only half-understood her words.

She’d heard that Fu Hua came from the Previous Era, but since they weren’t yet close, she didn’t pry further.

”For now, you’ll rest here,” Setsuna said with a calm smile. ”Kallen will explain more about the Starsea Empire.”

”We still have unfinished matters in the Honkai world. Once everything’s settled, I’ll bring you to the Imperial Capital.”

”If you need anything, ask the Angeloids. If there’s something you’d like to know, come to me directly. I can answer most questions.”

Thanks to time traversal, Setsuna knew it wouldn’t take long to ”conquer” this civilization.

All he needed to do was jump to the correct temporal nodes, retrieve key individuals, and bring the entire world under his control.

”Mm...”

Standing before him, Cecilia felt a faint sense of intimidation.

As a leader herself, she could tell—this man’s presence was vastly different from Otto’s.

After all, one commanded an interstellar empire spanning the stars; the other merely ruled a small planetary organization.

”May I ask... what exactly do you intend to do in this world?”

It was the question weighing most on her mind.

Within Schicksal, there were countless theories about the Starsea Empire.

They’d appeared several times—defeating the eastern crusade, taking Kallen, abducting the First Herrscher and Honkai scientists... yet their motives remained a mystery.

Some claimed they were tied to the Honkai, orchestrating events behind the scenes. Others insisted they sought to conquer the Earth.

”Two things,” Setsuna replied, raising his hand.

”First, to eliminate the Honkai. Second, to conquer the world and bring it under the Empire’s dominion.”

”Ah...”

Cecilia glanced at Kallen, then back at Setsuna—his answer was both expected and staggering.

”Then... why bring us aboard?”

Cecilia asked carefully again. She still didn’t quite understand why she, of all people, was brought here.

”Well...”

Setsuna thought for a moment, then answered bluntly:

”I like you. Rather than leaving you on Earth to keep fighting and scheming with the other natives and the Honkai, I’d rather bring you here for protection.”

”Think of it as me giving you a little privilege.”

He reached out and pinched Cecilia’s cheek gently.

At her young age, there was still a hint of maidenly shyness in her expression.

”Ah... th-this...”

Cecilia’s face turned scarlet.

His words were too straightforward—did that mean he liked her?

Before this man, who commanded hundreds of shipgirls, Spirits, and otherworldly maidens, the innocent girl felt like a blank page.

”Commander, stop teasing her,” Kallen puffed her cheeks. ”Let them have some time alone to get used to the place.”

To her, Cecilia was somewhat of a junior—gentle, kind, and a bit like her younger self. She was sure they’d get along well.

”When you first came aboard, you were just like her—nervous, polite, always speaking formally. Now look at you, making demands already.”

Setsuna grinned, pinching Kallen’s cheek next.

”You’ve gone bad.”

”I have not!” Kallen’s face turned red as she protested angrily.

”See? You even talk back now. Who knows what you’ll do next.”

”Hey?!—”

”...”

In any case, Cecilia and the others soon confirmed that Setsuna bore them no ill will. They settled down aboard the ship peacefully.

In a way, the Starsea Empire’s goal was similar to Schicksal’s—to defeat the Honkai.

Of course, there was a major difference in the second goal: conquering the world. That was bound to cause conflict.

Judging by that, Cecilia seriously considered contacting Schicksal’s leadership—to tell them not to do anything stupid and just surrender early.

...

”That girl, Cecilia, has a rather special background...”

A few days later.

The ship’s science lolis and the Honkai researchers—Einstein and the others—came to report to Setsuna.

”The secret weapon Schicksal was transporting, the so-called Herrscher Slayer, is actually Cecilia herself. Otto developed her as a biological countermeasure against future Herrschers.”

”Her Saint Blood can neutralize Honkai energy in an instant—quite overpowered, really.”

”This might be related to the Schariac family’s bloodline. We’re currently tracing the lineage of their ancestor...”

”Eliminating Honkai energy, huh...”

Of course, Setsuna was already aware of Cecilia’s ability. But unlike in the original timeline, he had no intention of letting her sacrifice herself to cleanse Honkai energy.

That would be a waste. Ordinary Herrschers could be crushed with one hand—far better to let her live happily.

”Actually, I’m a little curious, Commander,” Grey said, tapping her chin while staring at the holographic interface. ”If you and Cecilia had a child, would the offspring be even stronger? Her genes are already rare and powerful among humans...”

”According to my calculations, there’s a 13.33% chance your child could inherit both a Wisdom Cube and high Honkai adaptability, and an 11.55% chance of inheriting the Saint Blood.”

”So, maybe you should hurry up and win her over—we could study the results later...”

Bonk—

Setsuna flicked her forehead.

”Stop acting like Otto. Instead of that nonsense, why don’t you focus on what we’re going to do about Durandal and Kiana?!”

After bringing Cecilia aboard, he realized their presence had drastically altered the Honkai world’s future.

Cecilia was Durandal’s mother—and, in a sense, also the mother of K-423, Kiana.

”Tsk tsk... The joys of oyakodon are fleeting, but fixing the future is a pain. Commander, you enjoyed seducing the mother—did you ever think about what comes next?”

The nanobot shook its head dramatically.

”...Weren’t you the one who made the retrieval plan and the target list? Didn’t you claim you could simulate every possible future in this world?”

Setsuna grabbed the little grey drone by the face, stretching its cheeks.

”Ehh—hey—ow ow ow—”

Grey flailed, trying to explain.

”Ahem! It’s all part of the plan!”

”We’ve simulated the future carefully. Kiana’s basically a fusion of the Herrscher of the Void and Durandal, right? If needed, we can just... synthesize her ourselves.”

”Relax—no one will be missing in your harem! And if by some chance someone is, I’ll just transform into her for you, okay?”

”???”

Setsuna spent a few minutes in thought. If a nanobot could perfectly simulate another person at the molecular level—

Replicating every cell, every tiny detail of the skin, even mimicking thought patterns flawlessly—

Then... would there truly be any difference between the two?

After pondering for a long while, he finally concluded: he still preferred the original.

Fortunately, though the little Grey didn’t always act serious, the Research Division had already prepared several contingency plans for such situations.

”We can backtrack each individual’s appearance by analyzing the conditions of their creation.”

”For example—K-423’s birth required the fusion of the Herrscher of the Void and Durandal’s DNA. Therefore, both Sirin, the Herrscher of the Void, and Durandal must exist.”

”As for Sirin... given Schicksal’s current behavior, she’ll surface sooner or later. Durandal, on the other hand, was born from the union of the Kaslana and Schariac bloodlines.”

On the holographic screen, the Research Division projected millions of lines of computational data in a branching tree structure—complex enough to make anyone dizzy.

Thankfully, the final conclusion was simple enough.

”So, our next step is to find another Schariac family member on Earth and arrange a union with the Kaslana family.”

Shua—

Before Setsuna, a complete genealogical record of the Schariac family appeared.

If Cecilia had been there, she would have been terrified.

From their 15th-century ancestors to the present generation, every member’s age, status, and current location were laid bare—scanned in perfect detail by Sophon.

Not even illegitimate children were excluded.

”After cross-referencing all data, we’ve identified a few potential matches. Let’s pick the one with the highest compatibility.”

”The rest will sort itself out—Otto and the Schariac family will handle the details. History will soon return to its proper trajectory.”

”...”

Setsuna had no idea how the AI managed to find several Schariac relatives he’d never even heard of—but the plan, absurd as it was, somehow made sense.

”This is a great victory for life sciences and genetics!”

The nanobot smacked its metallic lips and protested.

”Do you know how long it took me to calculate all this just to satisfy your bizarre tastes and collection habits? Ugh—wanting both the daughter and the mother, who even does that?!”

”—I’ll give you a month off.”

”Two months. And invite me to the next party.”

”...You’re not allowed to transform into anything weird.”

”Deal.”

Whoosh—

Setsuna didn’t concern himself with the Research Division’s precise methods.

When a super-civilization masters mathematical control over causality, manipulating the natives of a lower world becomes trivial.

A small, subtle action could trigger a butterfly effect—producing monumental changes years or decades later.

In an old sci-fi film, a genius assassin once killed a man using nothing more than a pencil.

He balanced the pencil precisely atop a trash can. Later, a splash from a passing car knocked it over. A passerby bent to pick it up, causing a commotion, which upset a fruit stall...

Everything proceeded exactly as predicted.

Moments later, a distracted driver ran a red light and struck the intended target—turning a premeditated murder into a perfect accident.

That was the art of predictive causality—turning chance into certainty.

The Research Division was now doing the same thing to the Honkai world, albeit on a far larger temporal scale.

”At the 1991 temporal node, our tasks here are complete.”

”It’s time to move to the next point in history.”

A few days later, Setsuna piloted the starship into hyperdimensional space, switching the coordinate axis from spatial to temporal.

He gazed down upon Earth, every detail reflected in his eyes.

Humm—

The starship unfolded across dimensions, surging toward the distant future.

...

At Schicksal headquarters, Otto Apocalypse sat in silence, deep in frustration.

The Herrscher Slayer had been taken.

Just like the First Herrscher and the Honkai scientists before her.

According to reports from the remaining forces, the Starsea Empire’s starship had launched a precise strike against them.

Under Fu Hua’s command, she subdued every Valkyrie, including Cecilia, with a single move.

”...”

Otto felt as though he were being harvested like a field of wheat.

The First Herrscher—gone. The scientists—abducted.

And now, even the Saint of the Schariac family—gone.

Cecilia had been his most important asset in preparing to face the next Herrscher. He had invested enormous effort into her development—only for her to be captured so easily.

”Um, Lord Otto,” one subordinate spoke cautiously. ”A certain branch member of the Schariac family has been growing close to Siegfried of the Kaslana family. The two houses are even discussing a possible union. Should we... intervene?”

Among the Three Great Houses of Schicksal, such an alliance would normally be a monumental affair.

”Who? What?” Otto glanced briefly at the report.

”Do whatever you like.”

At this point, Siegfried was nothing more than a rebellious wanderer, and that Schariac member—just a minor figure, hardly worth his attention.

His thoughts were consumed by Cecilia’s disappearance—and the Starsea Empire.

”Even Schicksal’s strongest Valkyrie couldn’t stand against the Shenzhou immortal...”

Otto fell deep into thought.

In their limited encounters, he’d realized that not only was their technology terrifyingly advanced, but that immortal woman’s strength was utterly incomprehensible.

Her victory over Schicksal’s armed divisions in Berlin forty years ago had been alarming enough. But now, reports indicated that Cecilia and two A-rank Valkyries had been defeated in a single blow.

”Why would she help the Starsea Empire...”

He tapped the desk repeatedly, lost in frustration.

No answer.

The School of Taixuan’s traces had long since vanished over the past five centuries.

”In five hundred years, their battle methods haven’t changed at all—neither their ships nor that immortal,” one Schicksal executive noted.

”...Indeed.”

Otto thought back to his own experiences. He had seen that same starship before—five centuries ago, during Schicksal’s holy war.

The same ship, the same Fu Hua, the same Angeloids descending from the heavens.

Identical to those he’d seen forty years ago... and again, just recently.

That was enough to confirm their identity beyond doubt.

”Wait...”

A realization struck him—bold and unsettling.

”In other words... their technology hasn’t advanced at all in five hundred years.”

In the 15th century, Schicksal’s armies had worshiped the Starsea Empire’s fleets as divine beings.

But now, in the 20th century, they understood that those so-called angels were, in truth, artificial combat intelligences.

Even if they still couldn’t defeat them, they no longer trembled in awe.

And as for the starships themselves...

Schicksal had already launched satellites into orbit and developed spacefaring vessels. With Honkai energy accelerating their progress, humanity was close to achieving manned spaceflight.

The enemy, once seen as omnipotent gods, was no longer beyond reach.

Otto had witnessed humanity’s progress firsthand. The technological gap was closing—slowly, but surely.

”Five hundred years ago, Schicksal’s soldiers knelt before the Starsea Empire’s fleet, believing they had met gods.”

”From now on, that will never happen again.”

Otto’s voice was calm but resolute. For the first time, he felt a spark of confidence—of defiance.

”Fu Hua likely represents one of their high-tier combatants. She’s personally intervened multiple times. If we take her as the standard...” He paused, tapping his chin. ”Then we must train more Valkyries—stronger ones.”

”And we must accelerate our exploration of the solar system. Reach the stars. Find traces of the Starsea Empire.”

After a moment of thought, he summoned Theresa.

Theresa still looked twelve years old, with her childlike appearance unchanged.

”Go to the Far East and establish a branch academy. Recruit girls with Honkai adaptability. Train them to control their powers—to become Valkyries.”

”Also, provide them with theoretical education in space navigation and interstellar combat. In the future, they will be Schicksal’s vanguard—our frontline against both the Honkai and the Starsea Empire.”

”You’ll oversee it personally.”

”Ah... I understand.”

Theresa nodded.

Over the decades, she had proven her strength—becoming one of Schicksal’s primary forces.

”So, we’re raising interstellar Valkyries now... how forward-thinking of us. What shall we call this academy?”

”You decide.”

”Alright.”

—

—

40 Advanced Chapters Available on Patreon:

Patreon.com/DaoOfHeaven