Crossover Shipgirls: Building a Dimensional Empire from Scratch

”If I fail again this time, I’ll turn into a little blonde twin-tailed loli with heterochromatic eyes, put on white stockings and a sailor uniform, tie myself up, and throw myself into the Commander’s bedroom.”

Inside the Research Division of the space station.

Grey, along with Tesla, Einstein, and the rest of the Honkai scientists, once again began to study a method to tear through space and resonate with the power of Finality.

”If you move any slower, the Commander will have cleared out the remaining Herrschers, and if he borrows the powers of the Herrscher of Sentience and Herrscher of the Void again, he’ll literally become Finality.”

”Tsk tsk tsk, the real deal—a complete collection of all Herrscher abilities. Uh, although it’s a mix of the Previous Era and the Current Era Herrscher Cores.”

Tesla shook her head as she complained.

”...And what’s with that strange description? Is that really not your inner desire?...”

Kayo Senju squinted her eyes and asked.

”No, I don’t have desires in the traditional sense. Everything I do is simulated through nanobots.”

”Two-one-seven,” Grey replied righteously.

”Of course, if the Commander has such preferences, I don’t mind fulfilling them.”

”No matter the form or the type of XP, I can satisfy it. I can become whatever he wants.”

”Human? Sure. Catgirl? Sure. Slime? I can even become that...”

”...”

Tesla still couldn’t quite get used to working alongside this shameless creature.

Holding her head, she pondered for a long time. An individual composed of hundreds of billions of nanobots was essentially an entire civilization.

Could such an existence even fall in love with a human? Could they... do further things?...

After thinking for a while, both the Lobster-head Doctor and Chicken-nest-head Doctor were severely shocked.

That XP was too advanced.

Thinking about it, though, within the Starsea Empire, it wasn’t even that strange.

Setsuna’s companions weren’t just Kancolle shipgirls, Spirits, and ordinary humans, but also dragons, Cthulhu girls, and all sorts of bizarre species—adding a robot to the list wasn’t much.

”Ahem, ahem, ahem, back to business, back to business...”

Grey knocked on the table and began laying out the plans on the holographic interface.

”This time, to avoid unexpected situations, I’ve designed five contingency plans, with a total of 236 improvements...”

”When we create an Imaginary Singularity and open the rift, we must withstand the Honkai Energy tide. As for magnitude... let’s design it to be twenty times the last collapse. No, make it fifty times, just in case.”

”No matter how ridiculous, it shouldn’t generate a few million levels of energy, right? Given this civilization’s scale, it shouldn’t be possible.”

”Uh...”

Einstein and Tesla were completely dazed.

Shamelessness aside, when it came to research, no one could surpass Grey.

The data she casually calculated and the plans she drew up required these geniuses a long time to comprehend.

”Wait a second, what’s this about a ’Cocoon of Finality Disassembly Plan’?!”

”Using the Cosmic Juggernaut to impact the Imaginary Tree? ...Well, that one’s somewhat normal.”

”And what’s this ’installing an Aetherophasic Engine anchor in the Sea of Quanta to extract its power’ nonsense?!”

They quickly found a bunch of world-shaking ideas.

”Hypothesis, hypothesis— ahem... don’t mind these small details.”

...

On the other side.

Kiana, after being brought up, happily leapt into Setsuna and Cecilia’s arms.

”Mama!”

The little white-haired bundle of fluff looked up, chattering excitedly about her experiences at school.

”I made lots of friends—Durandal, Bronya, and the Raiden family’s eldest daughter, Raiden Mei...”

”Teacher Shigure Kira is really pretty, like an idol, but she sings terribly!!! And Teacher Himeko really loves to drink—one time she got drunk, and we had to carry her back...”

”Oh, and I passed all my exams! Mm, well, I ran into a little bit of trouble...”

Cecilia listened gently to her rambling.

Compared to life on the space station, Kiana had indeed become much more cheerful at St. Freya Academy.

”Sending her there really was a good idea...”

The mother-in-law showed a knowing smile.

”What were those dolls I just saw?” Kiana asked.

”They... were a bit scary. They said I wasn’t a real human or something...”

”Just think of it as a dream,” Setsuna rubbed her head.

There was no need to explain too much to Kiana right now.

”Oh...” Kiana half-understood, half-didn’t. The bizarre setup and eerie dolls of the Theater of Domination did feel dreamlike.

She pressed her head against Cecilia’s chest, rubbing gently. It was warm and comforting.

No matter what happened, someone would always be there to take care of her.

The traces of despair and negativity that she had picked up from the Theater of Domination vanished in an instant.

”Can I bring my friends next time?” Kiana tugged on Setsuna’s sleeve and asked.

”They’ve never been on a spaceship, and they’ve never seen the stars.”

”Theresa said I can join Schicksal’s first astronaut team—can I bring them along when the time comes?”

”Of course,” Setsuna smiled, pinching her cheek.

”You can give them a surprise.”

”Mm!” Kiana nodded firmly.

”By the way, Kiana, there’s something I need to tell you,” Cecilia patted her shoulder and spoke seriously.

”The Commander has to deal with something very important for this world.”

”It will take some time. During that period, you might not be able to contact him, but don’t be afraid.”

”When you’re in danger, I and the other sisters will look after you.”

”Oh...” Kiana thought for a moment in confusion.

”Is Papa going on a long trip?”

”You could think of it that way. When you’re older, I’ll explain it to you in detail,” Setsuna answered.

”It’s okay! Kiana’s not afraid!” The little white-haired bundle puffed up her chest proudly.

”I’ll study hard at the academy! Maybe when I see Papa again, I’ll have grown up and become the strongest Valkyrie—and just like Kayo Senju said, I’ll marry...”

”Huh???” Cecilia’s face turned black, and she gently karate-chopped Kiana on the head.

How strange—her daughter was still so young, yet already wanted to steal the Commander.

After a brief bit of playful scolding, they noticed the time was almost up.

Whir—

Under the effect of the teleportation spell, Kiana was bathed in Illustrious light. In the blink of an eye, the scenery around her shifted to her dorm room.

”Huh?”

Lying on her bed, she looked around for a moment.

Outside the window, dawn was just breaking—all that had happened had taken no more than a single night.

For a moment, she wondered if it had all been a dream.

But the warmth on her face was real, and when she reached into her pocket, she found the little snacks Cecilia had given her.

”Mmm...” Raiden Mei was the first to wake, yawning softly.

Seeing Kiana already up and sitting upright, she looked a little surprised.

”Up so early? Weren’t you the one who never wakes up no matter how much we call you?”

”Mhm! Here, for you!” Kiana handed her two packs of snacks.

”Oh... thanks,” Mei said, a bit surprised by Kiana’s cheerful demeanor.

”Is it because today’s the Honkai Beast subjugation mission? You’re too excited to sleep? Or did you have a nice dream?...”

”A dream, huh...” Kiana shook her head lightly, tidying her hair before glancing toward the sky.

”It was a very warm dream.”

”Herrscher of the Void... no, I’m Kiana!”

...

Engineering Department of the Space Station.

Countless Bulins were studying the blueprints, holding meow-meow hammers, drills, wrenches, and all sorts of tools, working around a gigantic machine.

Its size was two or three times larger than the one used in the previous experiment, giving it a towering, sky-reaching appearance.

”Hmm...”

”This time, there shouldn’t be any more problems.”

Nanobots scanned all the data on the holographic interface.

”Its impact resistance is dozens of times greater than before. Even if it gets hit directly by a Honkai Energy tide, it won’t be affected.”

”Even if a collapse erupts right here, I can still send the Commander straight to the Cocoon of Finality.”

”Huh...”

Einstein, Tesla, and the others were also running their final calculations.

”Come to think of it, we were just natives not long ago...”

”How long has it been, and now we’re already working on projects that touch the truths of the world??!...”

...

On the other side—

Clack—

While the Engineering Department continued their grand research, Setsuna was studying the new authority he had taken from the Herrscher of Dominance.

In the boundless violet void, he wandered around the Theater of Domination, observing his surroundings.

Closing his eyes, he sensed for a moment.

This was a separate extradimensional space, completely detached from the real plane, located within the cracks of spacetime. As an extension of the Herrscher of Dominance, it was bound to its Herrscher Core.

After erasing the traces of the Herrscher of Dominance’s existence, the Theater of Domination, which was once filled with despair and oppressive emotions, now felt much lighter.

Only Honkai Energy still flowed throughout the world.

”Oh...”

Cecilia, Gudako, and the others who came to watch joined him inside the Theater of Domination.

”So this is basically a portable subspace that you can open anytime? That’s pretty convenient. Even more than a Reality Marble,” Gudako smacked her lips.

The last time she came here, she’d been too busy wrecking things to notice how spacious the place actually was.

”To be precise, it can forcibly drag most people inside as well,” Setsuna added.

The Theater of Domination didn’t need the target’s consent to pull them in—as long as their power levels weren’t too far apart, anyone could be dragged inside.

”Also, the Herrscher of Dominance’s core ability—as the name suggests—is domination. The Herrscher of Dominance used to mentally break people here with words, then turn them into puppets or dolls.”

”In theory, I can do the same thing—forcibly dominate a person with authority... though it does sound rather perverted.”

The Herrscher of Dominance had used that method only because they were too weak individually.

He himself had no need to steal Herrscher powers. In the Starsea Empire, the only other ones possessing Herrscher Cores besides him were Kiana and Senti.

And he had no intention of turning others into marionettes. Puppets made through mental control were inferior in every practical way to Angeloids.

”Uh, so you haven’t really figured out what to use the Theater of Domination for?” Gudako tilted her head.

”Correct,” Setsuna replied. ”Do you have any suggestions?”

”Hmm...” Everyone fell into deep thought.

”Use it to host parties.”

Without hesitation, the embodiment of human evil spoke.

”It’s a portable subspace, super convenient! Even more so than the Eternal Snowfall’s hull—sure, the area and content are a bit limited, but you’ve got the Authority of Reason’s authority, right? You can create whatever you want. When you’re bored, you can just come in here with your sweetheart—nobody will ever find you, tsk tsk tsk...”

”???”

Cecilia and Kallen were speechless at Gudako’s shamelessness.

”What are you even saying? Herrscher authority is a serious matter, how could you possibly...”

Before she could finish, Setsuna nodded.

”Makes sense.”

”Until I think of a better use, that’s actually a decent idea.”

”Hey, what?!” Cecilia was dumbfounded.

”Are you serious?!”

”Of course. Or do you have a better proposal?”

”Um... no...”

Whoosh—

Setsuna spread his hands, invoking the Herrscher of Reason’s authority.

The scene before their eyes began to change dramatically.

Heaven and earth were born anew.

Everyone felt the same overwhelming sensation.

Under the influence of Honkai Energy, the once-towering Theater of Domination dissolved like bubbles, vanishing into nothing.

Then, in an instant, the world expanded countless times over.

The space around them stretched to its limits; chaotic Honkai Energy condensed into tangible matter.

Originally, there had been nothing but endless void surrounding the Theater—oppressive and somber.

But suddenly, Cecilia noticed a ray of sunlight piercing through the clouds, shining down upon her.

”The sun? How can there be a sun here?”

Looking up, she was nearly stunned.

A golden sun was slowly forming in the sky, its shape still unstable, like a sphere of liquid.

”Fix.”

Setsuna extended his hand and clenched lightly.

Crack—

The sun immediately stabilized, a blazing golden orb hanging high in the sky. Its light shone across the land, dispelling all gloom from the Theater of Domination.

The once-depressive atmosphere vanished entirely; under the gentle warmth of springlike sunlight, even their hearts felt lighter.

”Wait!!!”

”Commander, are you creating a sun?! Using the Herrscher of Reason’s power?!”

Kallen was utterly dumbfounded by the sheer scale of Setsuna’s feat.

”Just a little trick,” Setsuna chuckled.

”This is the Herrscher of Dominance’s space. Using Honkai Energy here has a multiplier effect—making a small sun isn’t that hard.”

”The Herrscher of Reason’s power is all about analysis and construction. In truth, the internal structure of a star is simpler than a dark matter reactor. As long as you have enough energy, you can shape one easily.”

”Depending on output, you can make it smaller, larger, turn it into an ordinary star, a red giant, a white dwarf—even a black hole.”

”Hiss...”

Everyone watching was speechless.

”As expected of a power closest to that of God...”

”We’re not done yet.”

Setsuna pressed his palms together.

Whoosh—

From the boundless void, sand, waves, and magnificent buildings began to form.

Like a printer producing an image, a grand landscape unfolded from under their feet, expanding before their eyes.

Cecilia looked down—she had been standing on the stone steps of the Theater of Domination, but in an instant, the scene beneath her turned into a wide, golden beach.

It stretched forward endlessly. In the far distance, oceans, trees, and roads all began to take shape.

Within just a few breaths, heaven and earth were transformed.

She now stood upon soft sand as rhythmic waves lapped gently against the shore. The sea breeze brushed her cheeks with a faint salty scent.

Looking up, the vast blue sky and drifting white clouds stretched endlessly, sunlight pouring warmly onto the earth.

Even the most famous coastal resort cities on Earth couldn’t compare.

What’s more—even small creatures appeared. She noticed crabs scuttling across the sand and seabirds foraging nearby.

”Creation itself?!” Kallen gasped.

”Just a minor trick. It only works because this space is mine,” Setsuna said with a casual smile.

”To do something like this in the external universe... I’d need to reach the Cocoon of Finality first.”

”That’s still absurdly overpowered!”

The group wandered around curiously.

The place was fully modeled after a seaside resort city, its size comparable to a small European country.

”Hmm... I can actually change it to other environments too,” Setsuna mused.

”If we get bored of this, I can make a tropical rainforest, a desert, a savanna... anything really.”

”So convenient...” Cecilia sighed sincerely. This power had been taken to an entirely new level.

”Wait—Commander, you’re seriously planning to vacation here?!”

”Mhm.” Setsuna nodded without hesitation.

He then opened a holographic interface and connected to the external comms.

”Nyarlathotep, Tohru, Formidable... are you free right now?”

”Hm? I suppose so. The Engineering Department’s building something, so we’re not too busy at the moment. Why? Commander, what’s up?...” Formidable brushed her hair.

”Then come over and play!”

In the next instant—

Whoosh—

Several figures appeared before them.

”Oh? Is this the Eternal Snowfall...? No, wait, where are we?!”

The shipgirls and dragon girls looked around in confusion.

”This will be our new group bonding spot.”

”Huh?” Tohru looked around curiously, sniffing the air.

”This... did you build this world with magic, Commander? Impressive—it feels completely real.”

”If it looks real, feels real, and works like reality, then it is real,” Setsuna said casually, wrapping an arm around Cecilia.

”Come on, everyone—let’s deepen our bonds.”

”Today’s theme is a seaside holiday. In a few days, we can switch to another scenario—praise be to Honkai!”

”???” Cecilia felt something was seriously off.

Wasn’t this place once the Theater of Domination? What had Setsuna turned it into now?

—

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