Crossover Shipgirls: Building a Dimensional Empire from Scratch

After the female mages from Frieren’s world continued their advanced studies at the Magic Academy, the newcomers from the Star Rail universe were also settled in.

Guinaifen, Firefly, Robin, the natives from Belobog, and the others were housed in the residential district, where Angeloids and Royal Maids guided them on a tour of the capital.

A utopian world without currency or crime, where everyone was equal and life resembled heaven on earth, dealt an enormous shock to these newcomers.

Every last one of them was dazzled. Even touring the solar system by spacecraft would take two or three months.

Once the more distant star regions and vassal worlds were included, fully understanding the Starsea Empire would require a very long time.

Fu Xuan wanted to exchange divination techniques with the Starsea Empire, so she arrived at the research center filled with anticipation.

”Oh, you want to learn our future-prediction technology? Easy enough.”

Kayo Senju stuffed a huge pile of documents into her arms.

Fu Xuan focused her gaze on them.

Advanced Mathematical Statistics, Fundamentals of Topology, Introduction to Partial Differential Equations, Lectures on Functional Analysis, Discrete Mathematics...

”What is all this?!”

Master Diviner Fu was stunned. After flipping through two pages, she found nearly everything incomprehensible. Staring at it for too long even made her dizzy.

”Mathematics!”

”We predict the future through mathematical laws. As long as you master enough mathematical knowledge, you can deduce the future through data analysis.”

”Isn’t it simple?!”

”...”

Fu Xuan considered the matter for several seconds.

”Forget it. I think the Matrix of Prescience works perfectly well.”

Elsewhere, Herta and Ruan Mei joined the Starsea Empire’s Research Department directly to conduct research in physics and biology.

”Uh, technically speaking, I signed a contract with the Commander for thirty Amber Eras, but now I’d like to extend it to a hundred Amber Eras... or perhaps a little longer.”

Inside the research hub above the Moon, The Herta witnessed the Starsea Empire’s advanced technology in person for the first time.

From the Azur Lane technology that formed the foundation of the nation, to the Arpeggio systems, Gundam technology, and the Galactic Wonders of the Stellaris era, those new inventions from other worlds completely captured her attention.

After plunging headfirst into the laboratory, she did not leave for two or three weeks. Angeloids handled all her necessities, and aside from a scant amount of sleep, she devoted every waking moment to reading research papers.

”Mm... Advanced faster-than-light technology and jump drives. No wonder the Starsea Empire can break through the boundaries of Imaginary Tides without relying on the power of Trailblaze.”

”What?! Linking biological brains together to construct a supercomputer?! What genius designed this thing?!”

”And what is a Cthulhu Evangelion? Why am I being told not to think too deeply about it?...”

She could not make sense of some of the Starsea Empire’s stranger technologies and even tried to investigate the wisdom of the Outer Gods.

Only after burning out several Herta puppets and destroying several pieces of research equipment did she temporarily give up.

In the Life Sciences Department, Mobius also welcomed her new colleague.

”Yo, you’re Ruan Mei, right? The Commander said you’re highly accomplished in biotechnology?...”

Mobius carefully studied the woman before her.

”To be honest, I didn’t like you when we first met on the Xianzhou. Research may be free in the Starsea Empire, but it still has boundaries.”

”If you casually experiment on other people, you’ll land yourself in serious trouble.”

The two had crossed paths before in the Star Rail universe, and the only impression Ruan Mei had left on Mobius was that of a mad scientist.

”I know.”

Ruan Mei smiled lightly and handed Mobius a pastry.

”Plum blossom cake. I preserved it myself. Don’t worry, there isn’t any anti-truth serum or anything else inside.”

”As for what you’re worried about... I promised the Commander that every one of my experiments would receive the test subject’s consent.”

”I have no intention of crossing any lines in his empire. However, aliens captured from other universes should be fair game, shouldn’t they?”

”Experiment on aliens however you please. I don’t care.”

Mobius spread her hands.

She noticed that although Ruan Mei remained as detached as ever, she was now unusually capable of considering problems from Setsuna’s perspective. Somehow, that made her seem less irritating.

”Fine. I hope we can get along.”

Their personalities made their interactions somewhat awkward, but their cooperation on research projects was extraordinarily efficient.

They soon established an ambitious project.

”Researching Aeons and cultivating an Emanator of Propagation to investigate the essence of life? Come to think of it, wasn’t the remains of Tayzzyronth, the Aeon of Propagation, being carried around by someone?”

Mobius opened a communication channel.

”Have the Sophons and Angeloids find Otto... no, Luocha. Bring me whatever he’s carrying.”

On the Xianzhou, a blond man who had just passed through the Jade Gate found himself surrounded by Cloud Knights and angels, leaving him utterly bewildered.

”What? Confiscating contraband? Is that really part of Xianzhou law?!”

Smack!

A Cloud Knight planted his guandao against the ground.

”It is now. The general just added it. Got a problem with that?”

...

Two weeks later.

While the newcomers gradually familiarized themselves with the Starsea Empire...

The large group of Spirits, Heroic Spirits, and ordinary girls stationed in the capital could no longer remain idle.

”Commander, we want to visit other worlds—”

”Mm.”

In the plaza before the administrative center, Setsuna gathered the members of every squad interested in joining the trailblazing expedition.

Aside from people like Qingque and Long Island, who only wanted to slack off, and easygoing Cthulhu girls like Nyaruko and Kuuko, who only stepped in as a last resort, most of the squads crowded over.

Six Astral Expresses hovered in midair.

One was the original train combined with the Cosmic Juggernaut, while the other five were mass-produced Astral Expresses built by the Bulins.

The mass-produced models were slightly smaller than the prototype, but their interior layouts and installed weaponry were complete. Even the Angeloid combat units aboard them were identical.

”Mm... We truly can trailblaze through a few more new worlds.”

Setsuna smiled as he looked over the crowd. Every squad was brimming with enthusiasm.

Given the difficulty of the next few worlds, unless they went out and explored now, most of them would probably be forced to remain in the capital and watch others perform.

Whoosh—

Setsuna projected the hyperdimensional star chart.

”We currently have six trains, allowing us to explore the greater multiverse in six different directions.”

”Each train can carry many squads. For the sake of maintaining balanced combat strength, I suggest spreading yourselves out. Avoid making some crews too weak and others too powerful.”

”Oh—”

Everyone nodded in agreement. To them, this was no different from forming a balanced party before heading out to clear a dungeon.

The Starsea Empire had no shortage of talented and extraordinary individuals. Whoever they managed to recruit would depend entirely on their own abilities.

”Commander, what happens if we accidentally enter a world with an excessively high power level?”

Kurome timidly raised her hand.

”The best option is to choose your direction on the map before departure. Even when we can’t investigate a world’s specific circumstances, we can still sense its general scale.”

Setsuna answered her.

”In addition, I’ll bestow some power upon each train to ensure it can protect you.”

”Should everything else fail, contact the homeland and request reinforcements.”

”Mm.”

Calling in a fleet or a Cthulhu legion from the homeland to beat someone up was certainly satisfying, but it would completely ruin the experience for the trailblazing squads.

They preferred exploring and conquering worlds through their own strength.

”Commander, how will the trailblazing squads aboard each train be arranged?”

Richelieu asked.

”Astral Express No. 1, the original train, will continue to be led by Himeko.”

Setsuna swept his gaze across the crowd and considered the matter briefly.

”As for Trains No. 2 through No. 6... each train will have one navigator. I’ll grant her the power of the Path of Trailblaze so she can operate the train, while each crew may form its own squads freely.”

”I’ll decide on the candidates later. I’ll also choose an Astral Express to accompany and visit other worlds with you.”

During his free time, he thought riding the Astral Express through the myriad worlds would be quite enjoyable, just as Akivili had once done.

”Ooooooh—”

The crowd erupted once more.

Himeko fell into a momentary daze. It felt as though she had returned to the legendary golden age of the Aeon of Trailblaze, when They traveled alongside the Nameless and fleets of Astral Expresses flowed ceaselessly through the universe.

”Commander, which train are you taking?”

”Me, me, me! Come with us!!!”

Excited voices rose one after another.

”He’ll decide when we depart. Otherwise, whichever train the Commander chooses will be packed beyond capacity.”

Belfast gestured for everyone to calm down.

”In that case, everyone, please make your preparations.”

”Astral Express fleet, prepare to depart.”

...

”Chaldea’s trailblazing squad is recruiting! Led by Ritsuka Fujimaru, with chief-god-class Heroic Spirits like Ishtar and Kukulkan ready to carry you! Join now!”

”Um, this is the Demon Slayer Corps. Are there any mages willing to team up with us?...”

”Megumin, we’re all fragile mages! Hurry up and recruit some frontliners!!!”

After the expedition plan was finalized, the entire capital erupted with excitement.

Each train could carry multiple squads at once, and the girls who wanted to venture outside began sending out invitations.

They freely formed teams based on their respective strengths.

Several powerful and approachable individuals in the Starsea Empire immediately became highly sought-after recruits.

”Huh? You want me to come too?...”

Inside the Imperial Grand Library, Lucoa had originally been humming while reading a book.

In the blink of an eye, the room was packed with people.

”Yes! We want to explore other worlds. Um... with Big Sister Lucoa accompanying us, we could probably visit someplace more difficult?”

Megumin said with her hand raised.

”Pfft—”

The great dragon girl laughed and rubbed her head.

”But managing the library is important too, you know? I still haven’t finished reading... no, organizing the materials the Commander brought back from other worlds.”

”Huh?—”

The Crimson Demon loli was deeply disappointed.

”Still, you can ask her instead. She’s very powerful too.”

Lucoa pointed outside.

Elma, wearing an off-shoulder coat with horns atop her head and a tail trailing behind her, was strolling down the street, stopping every few steps as she ate and looked around.

Ever since arriving in the Starsea Empire, she had spent most of her time eating, drinking, and having fun. She spoke extremely highly of the capital’s food.

”Come to think of it, there’s another little one in our world who wants to visit this place. Why don’t you bring her back with you?”

Lucoa transmitted a file to Megumin.

”Oh? Ilulu?...”

The Crimson Demon loli leaned over and saw that it showed a young dragon girl.

”Tsk. She looks like a little kid too...”

On Mount Taixuan...

Sushang, who had continued training in Taixuan swordsmanship under Fu Hua, immediately decided to cling to her grandmaster’s thigh upon receiving the news.

”Immortal, may I go out and take a look too?”

”No. Until you achieve mastery of swordsmanship and learn Eminence, you must devote yourself fully to cultivation. Do not entertain distracting thoughts.”

Fu Hua rejected her outright.

”Huh?—”

”Eminence? Doesn’t that mean I’ll have to stay on Mount Taixuan for several years?...”

”Your talent and foundation are excellent, but your temperament is too impatient. If you can devote yourself to cultivation for some time, you will undoubtedly accomplish great things.”

”Ah—”

Just as Sushang sank into despair, the diminutive Cangxuan, who was sitting atop a Taiji sphere and watching the commotion, suddenly raised her hand.

”Why don’t you take them along? Your disciples have spent quite some time on Mount Taixuan too, but they haven’t gone out anywhere yet.”

”Should the opportunity arise, you can treat it as an external training excursion for the sect.”

”Mm?...”

The sword hilt Fu Hua had been using to rap Sushang on the head stopped in midair. She looked around and saw that Qin Suyi and the others were also filled with anticipation.

”Fine. I’ll ask the Commander.”

...

Several more days passed.

Once the preparations for departure were complete, a tangled assortment of team formation reports and plans arrived in Setsuna’s hands.

After making minor adjustments to the members of each squad, he gathered everyone once more in the capital’s plaza.

Whoosh—

Setsuna opened a massive holographic interface before him.

”Now then, based on everyone’s desired team arrangements and the combat strength of each train crew, we’ve provisionally established six trailblazing squads.”

”Each trailblazing squad will have one navigator who pilots an Astral Express and trailblazes freely.”

He tapped the interface.

The crowd split into several groups.

”The first squad will be led by Himeko and consist of the original train crew. Mm, Bronya, Silver Wolf... you want to join too? That’s fine.”

The previous train crew had already grown extremely familiar with one another. After recruiting a few more companions, they filled an entire train.

At a glance, the group included two Himekos, three Bronyas, and two Seeles. With so many alternate counterparts gathered together, it was exceptionally lively.

”The second squad will be led by Elma. It will include the Konosuba team and some Magic Academy students who wish to travel. You have one small assignment to complete, after which you may choose your destination freely.”

”Oh—”

Led by the dragon girl, the Crimson Demon lolis skipped and bounced aboard the Astral Express.

”The third squad will consist of Fu Hua, Sushang, your disciples, the Demon Slayer Corps, and the Herrscher of Sentience.”

”The fourth squad will consist of the Overlord team, the Pleiades, and the Goblin Slayer team.”

”Understood—”

Sword Maiden gripped her sword-shaped scales and joined the group alongside the Priestess and the others.

After spending some time in the Starsea Empire, her appearance and figure had matured into elegant fullness. She gracefully saluted Setsuna.

”Thank you, Commander. I’ll do my best to complete the mission.”

”Mm.”

Setsuna then designated the final two squads.

”Elysia and Ritsuka Fujimaru, each of you will lead a trailblazing squad as well.”

In addition to several Valkyries, Elysia’s team included two particularly distinctive figures.

The Herrscher of Finality and the Herrscher of the Void nodded faintly to her and stood nearby.

The Herrscher of the Void had been captured long ago during the Great Honkai, while the Herrscher of Finality had been created by Setsuna.

The two of them possessed even less emotion than Angeloids. Aside from carrying out orders, they never did anything unnecessary, so Setsuna simply assigned them both to Elysia.

”Oh? I’m Origin, and you’re Finality?”

Elysia poked the Herrscher of Finality. The latter remained expressionless and stared straight ahead, waiting only for her orders.

”Yes.”

”Let’s get along?”

”Thank you.”

”Do you have any special requests or anything you like? We can bring it aboard the train~”

”No.”

”...”

These two Herrschers were genuinely devoid of humanity, emotionless combat machines in the truest sense.

”All right. She looks like she can fight pretty well, so I’ll take her out for a little trip. Hopefully nothing goes wrong~”

Elysia agreed.

Gudako’s team naturally consisted of Chaldea’s Heroic Spirits. She also brought along Akame, Kurome, the other members of Night Raid, and the little gray-haired girl.

The Stellaron brat and the Beast of Humanity immediately hit it off, becoming sworn sisters from different parents in no time at all and sticking together.

Click—

The six trailblazing squads boarded their respective Astral Expresses and curiously examined the interiors.

”Wait, why is there a Herta puppet on every single train?!”

The crews stared in bewilderment at the Herta puppets seated inside, waving in greeting.

They wore identical Lolita dresses and berets, resembling NPCs stationed aboard the trains.

”Madam Herta has many research projects to handle in the Research Department, but she refuses to give up the opportunity to explore other worlds. Therefore, we will collect information from other universes on her behalf.”

The Herta puppets answered.

”...Fine.”

After thinking about it, everyone agreed that this was indeed an extremely Herta-like solution.

In any case, no one minded having another genius aboard as an adviser.

”Master, Master, I want to go too—”

Jibril followed behind Setsuna, tugging pitifully at the corner of his clothes as she looked up at him.

”If you’re going to eliminate and conquer enemies, take me with you!”

”I’ve been in the capital for so long, but I haven’t gone out to fight even once.”

Flügel were weapons designed to slay gods. Not only did they possess exceptional combat capabilities, but they were also extremely warlike. After undergoing several enhancements in the Starsea Empire, little Jibril felt invincible.

Schwi poked Setsuna as well.

”Schwi wants... to come too. Schwi is very strong now.”

”All right.”

Setsuna rubbed the heads of the two little girls, then looked toward the six eager train crews.

”Himeko, I’ll accompany your crew on this journey.”

”When I have time, I may also visit the other trains.”

”Understood.”

Himeko was both delighted and somewhat overwhelmed by the honor.

Hum—

Setsuna selected several directions on the hyperdimensional star chart and transmitted them to every trailblazing crew.

”Now then, prepare to depart.”

”I’m sure everyone already understands the principles and ideals of trailblazing. Contact me or the Starsea Empire’s homeland immediately should any problems arise.”

”Understood!”

Boom!—

A surge of imaginary tides erupted.

The Astral Expresses rose into the sky one after another and charged upward.

In an instant, they broke through the atmosphere and transformed into streaking meteors that crossed the void of space.

Protected by the power of Trailblaze, they traversed countless light-years in the blink of an eye and arrived at the edge of the universe.

Rumble!—

A radiance more dazzling than a supernova flashed, and the Astral Express fleet vanished beyond the boundary of space-time.

—

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