Crossover Shipgirls: Building a Dimensional Empire from Scratch

Boom!—

The Astral Express departed the Solar System once again.

”Commander, hurry up and come over. I’ve been waiting for you here forever~”

Elysia’s avatar appeared on the holographic interface, making a cute face at Setsuna.

”All right.”

Setsuna suspected that Elysia simply wanted an excuse to spend time with him. That world was not particularly difficult for Crew Five.

Still, he did not mind. Since it was on the way, there was no harm in Trailblazing another new world.

The Astral Express crew would wander through the sea of stars in a vast circuit, only returning home to rest and resupply after illuminating and Trailblazing enough worlds and filling the train cars with passengers.

”Are you coming with me, or are you going to operate independently?”

He contacted Crew Six, which had been following behind them.

”We’re coming with you!!”

Gudako and the little gray-haired girl answered without hesitation.

”If I didn’t know about it, that’d be one thing. But now that there’s a new world, of course we have to go take a look.”

”Once we’re finished conquering this world, we can go Trailblaze somewhere else afterward.”

”All right.”

Setsuna contacted Albedo as well.

After temporarily withdrawing from Haruhi Suzumiya’s world, they had been standing by.

”Supreme One, we are currently traveling toward another unfamiliar world.”

Crew Four marked a location on the transdimensional star chart.

”We have confirmed that this world’s overall level is low. Its technological development is estimated to be only equivalent to a pre-spaceflight human civilization, with only a very small amount of supernatural power that may be concealed within human society.”

”Oh. Then be careful anyway. Call me if anything happens.”

There were far too many worlds consisting of a modern society with a small amount of supernatural power mixed in, so Setsuna could not immediately guess which one it was.

After thinking about it, he figured there was no way they would keep running into high-level worlds one after another.

”Understood! This time, we shall absolutely live up to the Supreme One’s expectations and wash away the disgrace of failing to Trailblaze the previous world!”

Albedo, Shalltear, and the Pleiades displayed a strange level of enthusiasm, apparently feeling deeply humiliated that Haruhi Suzumiya had frightened them into retreating.

They were determined to recover their dignity in the next world.

”Me? Am I really that scary?”

Haruhi had no idea what they were talking about and waved at Albedo through the holographic connection.

”Want to come play together sometime?”

”...”

Albedo and Yuri exchanged a glance, clearly wanting to say something but ultimately remaining silent.

Boom—

Crew Four’s Trailblaze power surged forward without hesitation, breaking through the boundary of the void and heading toward another universe.

”Then we’ll keep moving too, pom!”

Pom-Pom waved a paw.

Hum...

In the blink of an eye, the Astral Express crossed countless galaxies and sped toward the edge of the universe.

”Estimated travel time for this journey is three days and fifteen hours. All passengers, please arrange your personal affairs accordingly.”

”Do not move between train cars during the warp, pom!”

Pom-Pom bobbed their head while making the announcement.

”Whoa...”

Haruhi Suzumiya, who was riding the train to Trailblaze another world for the first time, was extremely excited.

Completely ignoring Pom-Pom’s rules, she first ran over to Himeko to look at the star chart, then scampered over to Setsuna.

”Commander, Commander! Are we leaving this universe now?”

”Mm. Everything here has already been taken care of. There’s a big sister waiting for us in another world.”

Setsuna smiled and rubbed her head.

”Oh...”

”What kind of world is it over there? Does it have an Earth? Is there anything interesting? Magic? Do they have magic?...”

She fired off a torrent of questions all at once, bursting with excitement.

”Oh, right. Will my information-manipulation abilities still work in another world?”

”Read the detailed information yourself.”

Setsuna sent her the intelligence report on the WorldEnd world.

”I want the Commander to tell me the story! There’s way too much stuff here. Reading it all is such a pain. Tell me about it yourself...”

Little Haruhi squeezed in front of Setsuna and tilted her head up, acting cute.

”...I’ll tell you tonight when I have time.”

Setsuna chuckled helplessly.

”As for your information-manipulation abilities, since they work inside a pocket universe, they should also have some effect in other universes.”

”Though they probably won’t be as powerful as they are here. This universe is your home field, and the information structure here isn’t particularly complex.”

”When dealing with the higher-level and more complicated information structures of other worlds, you may need to learn some techniques before you can manipulate them.”

”Oh...”

Haruhi only half understood.

Together with Nagato and Ryoko Asakura, she followed Himeko and the Angeloids around the train, touring the different cars and greeting the other members of the crew.

”These are your dormitories. This is the observation car, and this is the party car...”

”Haruhi Suzumiya, if you need anything, contact the Angeloids or the Commander first. Don’t use information manipulation whenever you feel like it!”

”—Got it!”

Haruhi dragged out the final word.

Inside the Astral Express, she could sense a force stabilizing the entire surrounding space. Not only could it withstand external attacks, even distorting space from within was extremely difficult.

Fortunately, everything inside the train was novel to her. Before this, Haruhi had only been an ordinary student on Earth and had never seen so much advanced equipment.

”Whoa, isn’t this a holographic game console?! The kind you only see in movies?!”

”And what’s this?!—Whoa, your games are dozens of generations ahead of Earth’s?!”

...

The train traveled through a tranquil sea of stars.

To reach one world from another, they first had to cross an entire universe before traversing the vast expanse of void beyond it.

A few days was neither especially long nor especially short.

Setsuna remained aboard the train. Aside from occasionally checking the star chart and keeping track of the other crews,

the rest of his time was spent fooling around and partying with the girls.

”Phew—”

”Ehehehehe... I’m so glad we’re on the same train as Master. The others must be dying of envy!”

Inside a private car near the front of the train, Jibril rubbed herself against Setsuna while nestled in his arms.

Her enormous breasts pressed against him and deformed from the pressure, though Jibril herself did not care in the slightest.

Aside from Himeko’s team, Crew One only had Jibril, Schwi, and the newly recruited passengers.

That meant that during their travels with the Astral Express crew, they effectively had the Commander all to themselves for long stretches of time.

Of course, there was one issue that barely qualified as a problem. With fewer people around, each of them naturally had to shoulder a greater share of the workload.

Even with the extraordinary physical constitution of a Flügel, Jibril felt somewhat exhausted and only wanted to cuddle against Setsuna and act spoiled.

The little sword beside them was sleeping soundly, hugging a pillow as she lay sprawled nearby.

Exhausting, but blissful.

Whoosh—

Several days passed in the blink of an eye.

The train crossed the boundless void, following the silver rails laid down by Crew Five until it arrived in another new world.

Its name immediately appeared on the star chart:

WorldEnd: What Do You Do at the End of the World? Are You Busy? Will You Save Us?

Hum—

Because Crew Five had already surveyed this universe beforehand, information immediately appeared on the transdimensional star chart the moment they entered the world.

[WorldEnd (Tier II Magical World)]

This world possessed widely utilized magical powers and lifeforms known as ”Visitors,” but lacked the ability to interfere with the structure of the universe.

Aside from humans, the planet was inhabited by large numbers of other races.

Comparison of strength between the two sides:

Military Strength: Like an Ant.

Economic Power: Like an Ant.

Technological Level: Like an Ant.

”Huh?”

Haruhi Suzumiya poked her head into the holographic interface, leaning against Setsuna as she stared at the projected information.

”What kind of world is this? Why is its name so long?!”

”All the other worlds I saw on the star chart only had a few words in their names!”

”Ha.”

Setsuna ruffled her hair.

”It’s a distinctive feature. You might run into worlds with even stranger names in the future.”

”For example, Do You Love Your Mom and Her Two-Hit Multi-Target Attacks? You could also shorten it to Your Mom’s Basic Attack Cleaves and Hits Twice.”

”???”

”Are you serious?!”

Jibril, Himeko, and Haruhi, who were watching from nearby, stared at him in astonishment.

”Mm-hmm.”

Setsuna neither confirmed nor denied it.

The Astral Express crossed the sea of stars from the edge of the universe, streaking across the boundless void like a meteor.

For most worlds, their stage encompassed an entire universe, yet the actual story usually took place on a single planet.

As long as one dealt with that planet, perhaps along with a few aliens at most, the entire world could essentially be brought under control.

The WorldEnd world was the same.

Whoosh—

Before long, they encountered another Astral Express waiting in a distant star system.

Clack—

The two trains docked together.

”Commander~”

”You took way too long! I’ve already gone down and toured the planet once! If you’d come any later, I would’ve taken all those girls and run away with them~”

A radiant pink figure leaped into his arms.

Elysia gave Setsuna a hug, then lightly kissed him on the lips.

”Sure. Then I’ll confiscate your Pink Elf Planet.”

Setsuna laughed, tightening his embrace and pinching her pretty cheek along the way.

”No! That was the token of love you gave me!”

Elysia puffed out her cheeks and punched him twice.

Then she looked over the new members of Crew One. There were many unfamiliar faces among them.

Some girls from all three worlds had come aboard.

”Commander conquers worlds so fast... Wait, that’s not it. You’ve tricked so many more girls into coming with you again!”

She pinched Setsuna.

Although she had long known that no one in the Starsea Empire could monopolize the Commander, seeing Crew One return from Trailblazing several worlds with nearly half its passengers replaced by unfamiliar faces still left Elysia somewhat overwhelmed.

There were mature women, young girls, and little girls alike.

”Ahem. I was invited by the Commander to temporarily travel with the Astral Express. If you ever require my assistance, please don’t hesitate to ask.”

Ariel greeted her with Shiro beside her.

Kumoko remained as socially anxious as ever. She glanced at Elysia and nodded.

Huh? This pink-haired girl is gorgeous. And she seems really close to the Commander? It can’t be what I’m thinking, can it?

She’s not human, right? There’s no way a human could look this perfect. No, wait. The Starsea Empire already has tons of weird people...

Hold on. What did she mean by saying the Commander tricked a bunch more girls? Does the Commander do this all the time?! Trick girls from different worlds into coming home with him, and then...

Using the parallel processing of several Ministers, Shiro imagined more than five thousand words’ worth of scenarios about Setsuna’s private life in an extremely short amount of time.

The resulting story was every bit as colorful as any erotic game or adult novel.

Yet none of it showed on her face. She merely inclined her head slightly toward Elysia.

”I... I’m Shiraori.”

”Commander gave me a body. For now, I’m traveling with him.”

”...A little aloof, aren’t you?”

Elysia did not quite understand, but found it impressive anyway.

Yoshino Tomotake, Mako Hitachi, and several other ordinary humans, along with Haruhi Suzumiya and Yuki Nagato, also came forward one after another to greet Crew Five.

Both sides looked at each other curiously.

Only after quite a while of noisy introductions did the three crews finally settle down.

Elysia brought Crew Five, while Gudako and the little gray-haired girl brought Crew Six. They gathered inside the Astral Express to discuss how they would jointly conquer this world.

”Ahem—”

”After arriving in this world, we carried out reconnaissance and intelligence-gathering operations.”

”Hmm... Because we wanted to resolve this world’s problems as perfectly as possible, we didn’t act recklessly. Instead, I invited the Commander over.”

Elysia projected the relevant information.

WorldEnd.

In ancient times, the entire planet contained nothing but Beasts and desert. Later, the lifeforms known as ”Visitors” arrived in this world as outsiders.

Of course, although the ”Visitors” of the WorldEnd universe were likewise regarded as gods, they were entirely different from the Aeons of the Honkai: Star Rail universe, which embody philosophical concepts.

They were simply a comparatively powerful race. In the extremely distant past, some disaster had forced them to abandon their homeland and begin wandering through the universe.

The Visitors traveled from world to world aboard spacecraft. After arriving here, they settled in the world of the Beasts.

The elders among the Visitors had grown tired of their lonely journey. They also wanted to remake the planet in the image of their original world, so most chose self-destruction, reducing their enormous souls to sand-like fragments and using them to curse the planet’s native lifeforms—the primordial Beasts.

Those fragments fused with the Beasts, creating humanity. Forests and sources of water were later created as well, and other races gradually came into existence.

Humanity became the dominant force on the planet for a very long time, but the number of Visitor soul fragments was finite.

As the human population gradually increased, the fragments could no longer sustain so many humans and slowly began losing their effect. Humanity started reverting to the Beasts they had originally been.

To prevent the world from being destroyed by the Beasts, the earth gods who served the Visitors decided to exterminate humanity. Humanity, in turn, chose to fight the Visitors for survival, intending to pulverize their souls into fragments and thereby prolong humanity’s existence.

In the end, humanity defeated three earth gods and killed one young Visitor, obtaining her soul.

Unfortunately, because the soul was not shattered thoroughly enough, it failed to produce sufficient fragments to save humanity. The Beasts were released, humanity became extinct, and the land returned to its original barren state as the survivors fled into the sky.

Among the floating islands formed from fragments of the earth gods and the remains of the Visitors, beastfolk replaced the humans of old and became the dominant race, maintaining a fragile ecological balance together with winged races, demon races, and others.

The floating continents were also frequently subjected to attacks from the Beasts, and the entire world was slowly sliding toward apocalypse and destruction as it struggled to survive.

”Hiss...”

The train crews who had just arrived in this world studied the information and fell into a long silence.

Not only was the setting complicated, it also involved all kinds of troublesome issues.

”Uh... So the humans in this world weren’t even pure-blooded humans, and they’ve already gone extinct? And the whole world looks like it’s doomed.”

Gudako was the first to raise her hand.

”We have to save the world again? Fine. I’m used to it. Remodeling a planet doesn’t seem that difficult anymore anyway...”

At present, three Astral Express trains had gathered in this world. The Seventeen Beasts might have been terrifying to the natives, but from the Starsea Empire’s perspective, they were probably useful for little more than being sliced apart for research.

The extinction of humanity was also somewhat complicated. The humans here were fundamentally fusion organisms created from Beasts and fragments of Visitors, making them different from humans in other worlds.

”I want specimens of the Beasts. Other races would be even better. I want to study the differences between this world’s Visitors and the Aeons of the Honkai: Star Rail universe.”

Catgirl Herta immediately made several requests. Elysia looked at her cat ears in confusion and simply assumed they were another one of Setsuna’s strange preferences.

”If possible, I’d also like to try using fragments of the Visitors and the Beasts here to create humans, as well as mixing Visitor fragments with Honkai Beasts and Danger Beasts for research.”

”Fine.”

Whoosh—

Setsuna pulled up Sophon’s scan report on this world and displayed a detailed list on the holographic interface.

”Then we’ll use the same conquest plan as we did in Kumoko’s world.”

”Bring back the people I need. As for the rest, you can do whatever you want...”

He had originally intended to say that the different crews should split up and operate independently while he remained aboard the Astral Express and waited for good news, calling him only if they encountered a problem they could not solve.

That was how they had handled the previous few worlds.

Smack—

”No!”

Elysia tugged at his sleeve.

”Commander, I waited all this time for you to come because I wanted to conquer this world together with you!”

”What’s the point of you sitting up here drinking coffee? Come with us, okay? There are lots of cute girls down there~”

”Huh?”

Compared to Jibril and Schwi, who obeyed orders one hundred percent and never questioned the reason behind them, Elysia’s initiative was maxed out.

She frequently acted spoiled with Setsuna and made all kinds of strange requests.

”You’re trying to use this as an excuse to go on a date with the Commander in this world, aren’t you?!”

Gudako was shocked.

”Mm-hmm~”

Elysia did not answer. She merely hummed a few lighthearted notes.

”Come down and take a look with us. Think of it as sightseeing while saving a world on the side, and maybe meeting a few girls along the way? The scenery in this world is completely different from Earth’s.”

”...”

Setsuna thought for a moment, then looked at the expectant girls of Crew Five and decided there was no harm in personally joining in for a casual round once in a while.

”All right. I’ll come with you.”

...

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