Crossover Shipgirls: Building a Dimensional Empire from Scratch

The ground operation ended swiftly.

The Angeloids swept through the Babylon Labs, annihilating all of Schicksal’s defensive forces.

”Ah...”

Sirin and the other test subjects stepped out of the experimental tower. The scene before them—flames, ruins, and angels soaring through the sky—left them momentarily stunned.

”Come, everyone, follow me.”

Cecilia held Sirin in her arms and led the children aboard the starship.

”W-wow...”

Both the angels and the gentle woman before them were strangers to the children.

Yet the maternal warmth radiating from Cecilia made them instinctively follow her.

After all, things couldn’t get worse than what they’d already endured. And someone who came to save them couldn’t possibly be their enemy.

Hum—

Once the starship took off, Ikaros led the Angeloid units in one final, commanding glance toward the Babylon Labs below.

Drawing her violet greatbow, she aimed at the target.

”Master ordered complete erasure of this site. I’ll handle it.”

BOOM—

An arrow of light shot forth.

The high-energy explosion engulfed the entire Siberian tundra. Within moments, the snow melted and evaporated.

This had been Schicksal’s secret base—isolated, surrounded only by scattered military outposts.

With a single strike, everything within hundreds of kilometers was reduced to nothingness. The surface structures and even underground bunkers were obliterated in the blast.

”Mission complete. Ikaros, returning.”

...

Click—

As the bridge hatch opened, the first thing Setsuna saw was Sirin clinging tightly to Cecilia’s side.

She gripped Cecilia’s hand, standing close behind her like a child hiding behind her mother.

”In a sense, this might be a historical convergence,” Setsuna mused, touching his chin.

In the original timeline, Cecilia had wanted to save Sirin—but after years of abuse, Sirin’s heart had been consumed by hatred, beyond redemption.

All Cecilia could do was sacrifice herself in her final moments, giving the girl a fleeting warmth.

But now, by shifting the timeline just slightly—letting Cecilia discover Sirin’s suffering earlier—

She had acted without hesitation, rewriting that tragedy into something new.

”Go get a medical checkup, and change into clean clothes.”

Setsuna patted Sirin’s head and called for an Angeloid.

”Give them food, and take them to bathe.”

It was hard to imagine that this trembling little girl would one day become the Herrscher of the Void.

”Mom...”

Sirin hid behind Cecilia, glancing timidly at Setsuna.

The man’s aura of command—and her memories of abuse—made her instinctively distrustful of adults.

”It’s alright, don’t be afraid. We won’t hurt you. Go on.”

Cecilia knelt down and gently pinched Sirin’s cheek.

”O-okay...”

Sirin obeyed, following the Angeloid away for her examination and a warm bath, looking back every few steps.

”...You really are fated to cross paths with Sirin,” Setsuna said with a smile.

”Oh, come on, I’m not even old enough to be a mom!”

Cecilia puffed her cheeks and shook her head.

”Hmm... but Sirin really is adorable. If I ever had a daughter, I wouldn’t mind if she were like her...”

”...Then Sirin’s yours to take care of from now on.”

Setsuna said it half-jokingly, but there was a faint light of reverence in his eyes.

”Then you’ll be the father?”

”...I suppose I could be.”

Cecilia paused for a moment, then, as Sirin and the others went off for their checkups, she sat beside Setsuna and looked at him seriously.

”You’ll take good care of those children, won’t you?”

”Of course. We have plenty of experience raising lolis.”

Setsuna grinned.

”...Huh? Well... alright then...”

Cecilia glanced at the research division full of young-looking girls. Remembering the data she’d read earlier—that lolis and Bulins were integral to the Empire—she sighed softly.

”Anyway, this mission was a complete success.”

Setsuna reviewed the data on the holographic display.

”Sirin is the future Herrscher of the Void. If given the opportunity, we might be able to guide her awakening—of course, under safe and controlled conditions.”

”After all, this generation of Herrschers still retains their humanity.”

Not only did he plan to train new Valkyries, Setsuna also intended to form a special Herrscher unit—to one day show a certain pink-haired elf.

”Mm-hm, we’ve also acquired one-third of a Kiana,” Senti added, crossing her arms and nodding.

”In due time, once we merge the powers of the Herrscher of the Void with those of Durandal and Sirin’s NDA, we can cultivate K423 ourselves.”

”Eh?”

Cecilia and Kallen were both stunned by the mention of ”Herrscher awakening.” On Earth, people exhausted every possible method to fight Herrschers—yet here he was, wanting to create one?

But after glancing at Senti watching nearby, they realized it wasn’t entirely absurd in the Starsea Empire.

If every Herrscher could be like the Herrscher of Sentience... perhaps it wasn’t such a bad idea after all.

”...”

After a moment of thought, Cecilia suddenly asked Setsuna a question.

”You came from the past... and traveled to this world’s future because you wanted to change something, didn’t you?”

She had noticed how deeply Setsuna understood the Honkai world—his knowledge bordered on clairvoyance.

Combined with the starship’s ability to traverse time, the conclusion was obvious.

”Yes.”

Setsuna nodded.

”So that means you know what the original timeline was like?”

Cecilia leaned closer, resting her chin on her hand. Kallen joined in as well, both curious about what might have happened if the Starsea Empire hadn’t intervened.

”Sirin was tortured for years in the Babylon Labs. Out of hatred for Schicksal, she awakened as the Herrscher of the Void.”

”She later discovered relics of the Previous Era on the moon and became an incredibly powerful multi-core Herrscher.”

”And in the end... well, you sacrificed yourself and perished together with her.”

Setsuna summarized briefly.

”Oh...”

Cecilia fell silent, deep in thought.

She opened Sirin’s file.

Originally, Sirin had been just an ordinary girl living in a small Siberian village. After her mother’s death, she lost her only source of affection and was later captured by Babylon Labs.

The more she read, the angrier she became. Both at Schicksal’s inhumane experiments—and at Sirin’s tragic fate.

”Commander... thank you,” Cecilia said sincerely.

”I never imagined... that Schicksal could be like this.”

”I had no idea such things happened beyond my sight... I’m just glad you were there.”

She drifted into a daze.

The strongest Valkyrie of Schicksal—having joined the Starsea Empire not long ago—had now led an assault on Schicksal’s own experimental facility.

Moments earlier, driven by righteous fury, she had reduced Babylon Labs to ruins.

Now that the adrenaline had faded, she realized just how extreme her actions had been.

The saint of the Schariac family had turned her weapon against Schicksal itself.

From this day forward, she would likely be branded a ”traitor.”

Yet Cecilia did not regret it. If she could return to that moment, she would still stand up for Sirin and those children.

She even wanted to confront the high-ranking members of the Three Great Houses and the Archbishop herself.

Still, her mind was now a tangled storm of conflict and emotion.

”We fight to protect humanity and resist the Honkai. If innocent children must be the price, then I’d rather have never joined the Valkyrie Corps.”

Cheng Lixue leaned against the wall and sighed.

After learning that Babylon Labs’ purpose was to artificially enhance Valkyries through Stigmata research, her emotions were a complicated mix of outrage and sorrow.

”...”

Kallen nodded silently. Witnessing such atrocities firsthand, she could no longer bear any association with Schicksal.

Just thinking about those self-righteous scientists who justified sacrificing children for their so-called ’greater good’ made her sick.

”It’s alright. We arrived early—everything can still be changed. They’ll have a new life now.”

Setsuna reassured them gently.

”Mm... thank you.”

Cecilia murmured softly, once again expressing her gratitude.

She thought that if the Starsea Empire could raise so many little girls with care, then perhaps it truly was a good place for them.

”I just hope you’ll take good care of the children—make their lives happier from now on.”

”No problem. That’s just like you.”

Setsuna smiled and pinched her cheek again.

”Ever thought about teaching at one of the Starsea Empire’s academies? I think you’d be perfect for looking after little girls.”

”Eh? ...Wait—what?”

...

For Sirin, stepping aboard a starship for the first time was overwhelming.

Everything around her felt utterly foreign—cold, sleek, and futuristic. The metallic tones reminded her of the sterile chill of the laboratory she had just escaped.

”Don’t be afraid.”

”We’ll take care of you~”

Kayo Senju led a group of research lolis and Angeloids over, surrounding the rescued children. They helped them bathe, change into clean clothes, and served them a warm meal.

”Later, we’ll arrange medical checkups for you. Don’t worry—the remaining Honkai energy in your bodies will be safely neutralized soon.”

”The Commander still has things to handle for now, so you’ll be staying with us. The ship has plenty of room.”

”O-okay...”

Seeing these girls—many around her age, some even younger—Sirin relaxed a little.

They were completely different from the adults in lab coats and masks. They had warmth.

”Thank you...”

Sirin couldn’t help admiring how confident and capable the little girls around her seemed.

”Um... that Commander—he’s your father, right?”

The question nearly made Kayo Senju choke on air.

”Uh, well... the Commander does like to think of us as his daughters, but you know, people should have... higher aspirations than that...”

”When we grow up, we’re all going to marry Onii-chan!”

The little loli said this with the utmost seriousness, puffing out her chest as if giving a life lesson.

”Ah?...”

...

”We’ve completed a full physical examination of Sirin and the other test subjects.”

”She had only recently been brought to Babylon Labs and underwent just one round of experiments. The Honkai energy hasn’t affected her too severely.”

A few hours later, the Life Sciences Division delivered a detailed report to Setsuna.

”However, some of the children suffered severe erosion. Their recovery will take time.”

”Unlike normal Honkai corruption that leads to zombification, the Schicksal scientists added additional complex compounds to the serums. We’ll need to perform bodily reconstruction for a few of them.”

Every case was documented in the report with meticulous detail.

Cecilia, Kallen, Cheng Lixue, and the others—who had only just calmed down—found their tempers flaring once again after reading it.

Babylon Labs had treated its test subjects like disposable materials. Leveraging Schicksal’s influence, they had scoured the world for orphans with Honkai adaptability, coercing or deceiving them into becoming human test subjects.

They had performed cruel, inhumane experiments on these children, discarding those who couldn’t withstand Honkai corrosion like failed lab mice.

”Ahem, but don’t worry.”

”We’ve been researching Honkai energy in depth for years. Even in severe cases, we can still save them.”

”Don’t underestimate the Life Sciences Division! Even if someone’s organs are completely destroyed, we can still bring them back!!”

The little loli scientist puffed out her chest proudly.

”And if all else fails, the Magic Division still has resurrection scrolls. We can just borrow a few.”

”...”

Einstein and Edison, both newcomers from the Honkai world, were dumbfounded.

They had thought the Starsea Empire’s supremacy lay purely in its technology—yet now they realized it also possessed artifacts capable of reversing life and death itself.

”Also, Sirin’s physiology is quite unique,” Kayo Senju added. ”Her Honkai adaptability surpasses every other subject. I recommend we keep special observation on her.”

”Understood. I’ll leave her in your care.”

Setsuna nodded.

He instructed the research lolis to settle Sirin and the rescued children aboard the ship.

Then, glancing down toward Earth, he expected exactly what followed.

Cecilia and Kallen’s actions had caused massive upheaval within Schicksal.

At Schicksal Headquarters, the high-ranking members of the Three Great Houses convened in an emergency meeting.

They repeatedly reviewed the fragmented surveillance footage.

The Babylon Labs had been utterly destroyed by Ikaros’ strike. The central facility left no survivors, forcing them to piece together the truth from fragments.

”All research personnel and security forces at the laboratory were eliminated by the enemy. Most of the data was also lost in the secondary Honkai reactor explosion.”

A subordinate reported the catastrophic losses to the council.

”All experimental subjects have vanished. The number of destroyed units and armored vehicles amounts to...”

”!!!”

Otto didn’t hear the rest. His mind was fixated on a single thought:

”Kallen is alive! Cecilia, and the Valkyrie squad that went missing years ago—they’re alive!”

He stood up instinctively, slamming a hand on the desk as he stared at the report.

The Kaslana and Schariac family representatives were stunned.

The strongest Valkyrie of five centuries past and the strongest Valkyrie of the present—fighting side by side to raid Schicksal’s own laboratory with the Starsea Empire.

What kind of madness was this?!

They all knew Babylon Labs had been conducting morally dubious experiments—but that information was strictly confidential.

To see it exposed so dramatically left many of them reeling.

Who leaked it? How did Kallen and Cecilia find the location?

Why were they working with the Starsea Empire?

The questions piled up, with no answers in sight.

”...Excellent.”

”Very good.”

Otto finally spoke, his words bizarrely calm.

After the initial shock faded, there was a strange glint of satisfaction in his eyes.

After five hundred years, he had finally found traces of Kallen again.

Though it wasn’t quite as he imagined, Kallen now stood on the opposite side—and even Cecilia had turned against him.

Still, any news at all was better than silence.

”Archbishop, this is treason,” declared the head of the Schariac family.

”For whatever reason, they joined forces with the Starsea Empire to attack us. They have betrayed Schicksal.”

”Based on these facts, I conclude that Kallen and Cecilia have defected. They are no longer part of our ranks.”

”...”

No one could comprehend why those Valkyries would suddenly attack the Babylon Labs.

A few who knew their personalities had a vague guess—but dared not speak it aloud.

”What now?” asked a representative of the Kaslana family.

”By regulation, traitors of Schicksal should be—”

”Kallen and Cecilia still have their uses,” Otto interrupted calmly. ”If we locate them again, report to me immediately.”

”As for the other two—life or death doesn’t matter.”

Cecilia had been painstakingly molded into a ”Herrscher Slayer.” Her Saint Blood was one in ten thousand—worth preserving. As for Kallen, that was pure personal bias.

But Cheng Lixue and Patricia—two A-rank Valkyries—he cared little for them.

If executing them would pacify the others, so be it.

”Deploy additional Valkyrie squads to guard the remaining laboratories. Each major facility must have at least three A-rank Valkyries stationed.”

”They seem to be targeting our scientific divisions...”

Otto leaned back in his chair, pondering.

From the First Herrscher incident to the disappearances of Einstein and Edison, and now the destruction of Babylon Labs—it was becoming clear.

The enemy seemed intent on halting Schicksal’s technological progress.

”Could it be... the Starsea Empire wants to suppress our science?!”

It was an outrageous conclusion—but one Otto couldn’t shake.

Shhh—

He opened a communication channel to Theresa.

”Archbishop?”

Theresa, still overseeing construction at St. Freya Academy, had no idea what was happening.

”Select a group of elite Valkyries for special training. We must reach space as soon as possible.”

”Train them to S-rank standards.”

Otto issued the order concisely.

”Ah... understood...”

Theresa found the command strange but agreed after a moment’s thought.

”So this is to advance the outer space exploration program? I see. We’ll look for girls with stronger adaptability and talent. They might not match Cecilia, but I’ll do my best.”

”...”

...

”I don’t need anyone’s pity or special treatment. If Schicksal ever repeats something like this again, I won’t show mercy.”

Aboard the transdimensional starship, Kallen observed everything below clearly.

”They... sigh...”

Cecilia shook her head and sighed softly.

The Sophon projected images of what she’d once been blind to—those finely dressed nobles and officials, revered as paragons of virtue, hiding such depravity behind closed doors.

Otto hadn’t ordered their deaths only because Cecilia’s Saint Blood was still valuable.

”For a time, Schicksal won’t dare resume such experiments. The losses were catastrophic—the Babylon Advanced Systems Division was completely annihilated by Ikaros,” Setsuna said, glancing at the intelligence report.

”So don’t worry.”

”Hmm...”

Kallen twirled a strand of her braid, thinking aloud.

”Before, I wanted Schicksal to surrender peacefully and become a vassal of the Starsea Empire... but now, I think we should just dismantle it entirely.”

”Those nobles... are truly disgusting.”

Pfft—

Setsuna couldn’t help but laugh.

”Perfect. You’ve officially become a model citizen of the Starsea Empire. In the Empire’s domain, organizations like that are, of course, illegal.”

”But before that—hold on. There’s still something we need to do.”

”To the next time node.”

Boom—

The starship surged forward once more, gliding through the currents of time.

Senti opened the holographic interface before them.

Shhh—

A massive tree-shaped projection expanded into view.

”Now that Sirin has been rescued, the Second Eruption won’t occur. The Herrscher of the Void’s power can be reclaimed later...”

”Most events tied to that disaster will never happen. The world will evolve along a different path.”

”Hmm, though that does mean someone might stay locked up for quite a while...”

—

—

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