Crossover Shipgirls: Building a Dimensional Empire from Scratch

Morning sunlight streamed through the curtains, casting warm stripes across the floor of the seaside villa bedroom.

Cecilia sat up, rubbing her head groggily.

”Ugh...”

She picked up a few pieces of clothing—all wrinkled and disheveled from their rough play last night.

”Commander, it’s all your fault! You ganged up on me...”

Cecilia pouted and pinched Setsuna twice.

”Ahem, gotta be a team player, gotta be a team player.”

Setsuna ruffled her hair, his gaze unconsciously sliding downward—stopping at a field of snow-white skin.

”Hey?!”

Cecilia couldn’t help but laugh in disbelief.

As a newly joined member, she had undoubtedly received an enthusiastic welcome from the veterans.

Though Valkyries had strong physiques, they couldn’t quite compare to shipgirls, dragon girls, or eldritch beings. After their ”in-depth exchange,” her body was sore all over this morning.

”You owe me clothes.”

She tossed a few torn scraps—and what was once a single ruined black stocking—at Setsuna’s feet. All his fault.

”Sure thing.”

Whoosh—

With a wave of his hand, Setsuna conjured an elegant set of lacy black lingerie.

”Here, I wanna see you wear this. Boosts attack speed.”

”Hey!!! Make me actual clothes, you pervert!!!”

Cecilia lunged at him, pinching hard.

After a brief tussle, they finally got dressed and headed to the dining room for breakfast.

As usual, most of the food was directly created by Setsuna, to everyone’s amazement.

”...You’re a little jealous, aren’t you?”

Not far away, Cheng Li and Lian whispered to each other.

They had also been dragged into the Theater of Domination and enjoyed the seaside kingdom’s ”vacation benefits.”

But when they remembered Setsuna’s nightly routine of hugging two girls to sleep, their expressions turned complicated.

”I saw you arrive pretty early—didn’t he take you?” Cheng Li asked curiously.

”...Why does that sound so weird?”

Kallen looked at Cecilia, feeling a subtle sense of defeat.

”You came here hundreds of years ago, right? Have you really just been cultivating in the Starsea Empire this whole time? Never involved in romance? As expected of the strongest Valkyrie.”

Cheng Li looked at her with genuine admiration. To her, Kallen was practically a relic of the past, a person from five centuries ago.

”...You’ll understand once you visit the capital,” Kallen said quietly.

She wanted to add—I never even got a chance.

With the Commander constantly surrounded by shipgirls, Heroic Spirits, Spirits, and mysterious women from other worlds, finding an opportunity was nearly impossible.

”Hmm... we’ve been playing here for a few days now. Maybe I should try a new scene,” Setsuna muttered.

”Where to next?”

Just as he was considering which environment to reshape the Theater of Domination into—

Beep—

A transmission came through from the nanobot link.

”Commander, what are you... doing right now...”

Grey looked around at the unfamiliar background, momentarily frozen.

”Wait, you’re inside the Theater of Domination?! You renovated it? Looks nice... Huh?! No wonder I couldn’t find Cecilia and Formidable—so you’ve been partying here?!!”

”...I’m testing authority functions,” Setsuna replied honestly.

”Testing? More like turning into the Herrscher of Parties! Your ship’s the Eternal Silver Party, and your power’s creating a Silver Party Kingdom?!”

Grey squinted, glancing at Cecilia’s flushed face beside him—quickly putting two and two together.

”You left me working in the Engineering Department while you came here to party?! Tsk tsk tsk, what moral decay...”

”No, wait, forget that—focus on the mission!”

...

An hour later.

Everyone had cleaned up and exited the extradimensional space of the Theater of Domination, returning to the experimental grounds of the space station.

A massive machine—several times larger than the previous model—stood ready.

”This is the Finality Destroyer MK-II. We’ve fully upgraded it from the Mark I to ensure it can withstand Honkai Energy tides. Even if Honkai erupts on-site, it’ll remain stable.”

”It can create an Imaginary Singularity, tear through the veil of reality, and send us directly to the Cocoon of Finality.”

”Huh...”

After the last experiment, Gudako was still skeptical.

”You sure there won’t be any accidents this time?”

”Absolutely, positively, definitely sure.”

Grey patted her chest with confidence.

”This machine’s power output is dozens of times stronger than before, and with the Commander’s strength, it’s 100% guaranteed to open a rift and transport us into the other dimension.”

”100%! No chance of failure!!”

”Alright then.”

Setsuna stood with the small team ready to investigate the Cocoon of Finality.

Behind him gathered Grey, Einstein, Tesla, and a group of researchers—along with Gudako, who came to watch, and Nyarlathotep, who didn’t trust them to behave.

[Honkai Energy guidance: ready]

[Simulating Finality energy... releasing Honkai Energy]

At the AI’s signal, Setsuna unleashed his full power. Having fused the Herrscher of Dominance’s authority, alongside the Herrscher of Sentience and a portion of the Herrscher of the Void’s power—he was now nearly indistinguishable from the true Herrscher of Finality.

Vmmm—

A storm of chaotic energy surged through the space station.

Beneath them came the sound of reality shattering.

Crack—

Shields expanded to isolate all Honkai Energy from leaking out.

”Relax! The power output this time is massive! Even if an Eruption occurs or something weird happens, it won’t interrupt the system!”

Grey stood proudly, arms crossed, eyes gleaming as she watched the holographic readings.

Boom—!

Rumble!!!

Once Setsuna’s power reached its limit, a rift opened beneath the space station.

”Commander, use your power to resonate with it.”

Setsuna complied, channeling an immense torrent of Honkai Energy into the rift.

”More... a little more...”

”Got it.”

The rift grew larger and larger, and just as it passed a critical threshold—

Zzzzt—

A colossal tear split open in the void.

”Wait, that’s too big—stop—”

Before she could finish—

Vmmm—

The world blurred before their eyes. They felt a sudden drop, as if falling through dimensions.

”What the hell—AAAAAHHHHH!!?!—”

No one knew how long it lasted.

When they opened their eyes again, they were still aboard the space station—for a moment, they thought it had been an illusion.

But when they turned to look out the window, the stars had changed.

No sun. No Earth.

The universe around them was nothing but void and ruin, with Honkai Energy drifting freely through the air.

Below them floated an enormous sphere.

Its surface was covered in cracks, and the surrounding space was shattered like glass, frozen mid-break, reflecting a chaotic swirl of colors.

At the center of the sphere’s largest fissure glowed a purple diamond symbol, radiating energy that surpassed the combined might of all previous Herrschers.

”.???”

”Eh?”

In the lab and nearby testing grounds, the lolis and onlookers—including Cecilia and Kallen—stared blankly.

”What... what is that thing?...”

”Uh...” Grey scratched her head awkwardly.

”Seems like... a little mishap. The Commander’s power was too strong when resonating with the Cocoon of Finality.”

”The rift expanded a hundred times larger than expected... and the entire space station resonated with it. So, uh... we all got teleported.”

”But that’s fine, right? I mean, mission accomplished!”

”???”

It took everyone a long moment to realize—they had literally teleported the entire space station into another dimension through sheer brute force.

”Can we even go back?!”

”Aaaahhh! Activate emergency power—!!”

The little lolis panicked, running around the lab in chaos.

”I’m here. What’s there to fear?”

Setsuna’s calm voice immediately silenced them all.

Everyone turned their gaze downward—toward the massive sphere below.

The Cocoon of Finality.

”Oh... so that’s the source of Honkai, huh?”

The scientists’ initial panic melted into fascination, their eyes sparkling with discovery.

Setsuna took a few steps forward.

He could feel the Cocoon reacting to his presence—a faint tremor rippled across its surface.

”...”

A question echoed within their minds, resonating like a thought broadcast:

Who are you?

From where do you come? And why have you come?

”Hoh? Mental communication?”

Grey stepped forward, clearing her throat.

”Ahem—show some respect.”

”Before you stands the Emperor of the Starsea Empire, Commander of the Fleet of Fog and Azur Lane, Savior of Lolis, Keeper of Catgirls, Destroyer of the Trisolaran Civilization, Master of Angeloids, Ally of the Great Old Ones, and Conqueror of EVA...”

”...”

The Cocoon of Finality went silent for a moment—as if it had crashed.

Then, a deep thought reverberated through space:

Too many of you. Send one.

”Hoh...”

Aboard the space station, Einstein, Tesla, and the other members of the Research Division leaned forward, curiously observing the Cocoon of Finality below.

They thought bringing the entire space station over was a massive win—with all their equipment here, studying the Cocoon would be much easier.

”Cocoon? You’re telling me this thing’s called a cocoon? It’s almost the size of a planet! What’s even inside that thing?!”

”It can respond to questions—like an autonomous intelligence system. Hmm... if I remember correctly, the Cocoon of Finality is designed to create beings of its own kind...” Tesla rubbed her temple.

”It’s the source of Honkai within the solar system. Every time a Herrscher is born, it represents the Honkai’s attempt to ’embrace’ reality.”

”But since the gap between Finality and humanity is too vast, that ’embrace’ always goes wrong—humanity can’t withstand the Honkai’s touch.”

”That’s why the Herrscher of Finality was granted the authority of ’Time’—to use endless trial and error to find the correct way for that ’embrace.’”

”Its influence on Earth has two possible outcomes: if the embrace succeeds, humanity becomes Finality; if it fails, Finality wipes the planet clean and resets civilization.”

”...”

Everyone fell silent for a long moment.

”This thing’s... kinda insane.”

Then again, it wasn’t exactly realistic to apply human morality to something like the Cocoon of Finality.

According to its logic, unless a miracle like Kiana happened again, the endless cycle would never stop.

”Commander, are you going? It seems like it only wants to talk to you.”

Grey gestured toward Setsuna.

”Can we at least scan it first...?”

The science lolis, armed with scanners and analysis tools, were visibly eager.

”You all stay here. I’ll go take a look.”

Setsuna leapt down.

Though the Cocoon appeared planet-sized from afar, the space warped as he approached.

He found himself standing on a mirrored surface—before him, the colossal Cocoon trembled faintly.

”I’m coming too!”

Boom—

Nyarlathotep landed behind him, pulling a crowbar from under her skirt and resting it on her shoulder.

Tap, tap—

Setsuna stepped across the mirrored surface, approaching the Cocoon of Finality.

The closer he got, the more intense the surrounding Honkai Energy became.

Who are you?

The voice echoed once again in his consciousness.

”Didn’t we go over introductions earlier? What, you want me to list my titles again?”

Setsuna grinned.

”...”

The Cocoon of Finality went silent, seemingly processing and analyzing that overwhelming list of bizarre titles.

Naturally, it couldn’t make sense of any of them.

Why have you come?

The Cocoon questioned again in his mind.

”Why else? To become Finality, of course.”

Setsuna answered without hesitation.

”Your purpose is to create your own kind, right? Well, I’ll make it easy—I’ll just stuff you into the Eternal Snowfall, and we’ll merge. You’ll become part of me.”

”???”

The Cocoon of Finality froze again.

In theory, it was supposed to meet a human who had become Finality.

But what was this guy?

Was he Finality?

He sort of was—but also... not.

He possessed most Herrscher powers, yet carried countless unknown elements that even the Cocoon couldn’t comprehend.

His control over Herrscher authority was strange—not as a Herrscher, but as someone manipulating it through some unfathomable means.

The Cocoon of Finality felt its logic circuits glitching.

What do you intend to do with the power of Finality?

”...”

Setsuna instinctively felt that this was an important question.

He thought for a moment.

”In the Starsea Empire, the power of Finality—or rather, Honkai Energy—is just like the Wisdom Cube, dark matter reactors, spiritual energy, or the Allspark.”

”It’s a tool. A part of the Empire—everywhere you look. It’s what allows us to set sail from the seas, into the stars, and beyond the universe itself.”

”We will master it, use it, and in time—whether it’s the power of Finality, Honkai Energy, or any other form of magic—it will spread across the vast multiverse alongside the Empire’s conquest.”

His philosophy resembled Kiana’s from the original timeline, though the Starsea Empire’s power far exceeded that of Earth. Here, countless world forces converged into one.

To him, the power of Finality was just like the META Cube, the Allspark, or spiritual energy—another system of power that could be used to achieve even greater things.

”...”

The massive sphere before him fell into prolonged silence.

”What’s happening?”

On the space station, the scientists, Cecilia, and the others leaned forward curiously.

They had no idea what was happening—all they could see was Setsuna standing before the Cocoon of Finality. After what looked like a brief exchange, everything went still.

”Did it refuse?”

Nyarlathotep stretched her neck.

”Negotiations failed? Should we prepare for a siege?”

”So what’s the plan? We taking it with us, or blowing it up? This thing looks kinda cursed...”

She tapped the ground with her crowbar.

”You wanna fight? Don’t blame me then, ehehhehe...”

Before she could finish—

Whether it was because Setsuna gave the right answer, or because the eldritch threat actually worked—

Vmmm—!

The Cocoon of Finality erupted with a radiant surge of light.

Whoosh—!

Setsuna reached out to touch it, and his vision was instantly pulled and stretched—as though being dragged through a tunnel of time and space.

He witnessed the Cocoon’s long history, flashing rapidly before his eyes.

Billions of years ago, the Cocoon of Finality arrived in the Solar System, settling first on Mars, nearly annihilating its native civilization.

Then, 250 million years ago, it destroyed Venus—once home to another advanced race.

Earth became its final stop. During the Previous Era, humanity, facing the threat of Honkai and the Herrschers, devised countless countermeasures:

The Divine Keys, the Project STIGMA, the Project EMBER, the Project ARK, Project VALUKA...

In their final moments, the scientists of the Previous Era finally grasped part of the Cocoon’s and Honkai’s true nature.

”One day, it fell from the heavens. Humanity looked up—and for the first time, saw the stars.”

”In the depths of the cosmos, perhaps there exists such beings—rooted in their worlds, born from their planets. But unlike us, they take it further, merging completely with their homeworlds.”

”Their will permeates the land, omnipresent and eternal. Their minds interlinked without barriers. If such a civilization truly exists, it would long for others like itself—to embrace them.”

It was akin to the Human Instrumentality Project—after reaching a certain point, all consciousness would merge into one.

Unfortunately, the Herrscher of Finality never granted them that chance—it reset the world entirely.

Boom—

An overwhelming torrent of energy surged into Setsuna’s body.

Unlike the other Herrscher powers he had wielded, the Cocoon of Finality was the one and only Imaginary Singularity—the singular Herrscher Core.

Every Herrscher across the Previous and Current Eras had merely been a fragment of its projection.

The Power of Finality encompassed all Herrscher abilities—and could even be infinitely divided into them.

”Hoh...”

Setsuna found the sensation fascinating.

He floated in a vast sea of energy, his mind flooded with abstract concepts and knowledge, which he had to carefully sort to understand their meaning.

After what felt like half an hour—

Crack... crackle—

The Cocoon’s surface split open, and Setsuna emerged from the light.

He stepped onto the mirrored surface, clenched his fists, and felt the new authority pulsing through him.

”Commander... what just happened?”

Nyarlathotep tilted her head. When Setsuna had touched the Cocoon, he vanished instantly, causing chaos among the researchers.

Grey had even been moments away from launching a forced entry to retrieve him.

Now, Setsuna looked... subtly different.

”Hmm...”

”In simple terms, the Cocoon of Finality embraced me. It hopes I’ll go further—to create more of its kind across the cosmos.”

Setsuna replied calmly.

”What?! The Cocoon actually acknowledged you?!”

Tesla nearly jumped.

”You’re not even from this world! I really thought we’d have to fight it—like last time! Didn’t the first experiment almost trigger a Honkai Eruption?!”

”Maybe it was just correcting itself out of instinct,” Setsuna smiled.

”The Cocoon isn’t really sentient—it’s a mechanism. The first time was probably a calibration error.”

”To it, I’m the most suitable candidate in existence.”

Someone who could fully adapt to Honkai Energy, embrace Finality itself, and make it part of an interstellar civilization.

Without a doubt, by the Cocoon’s standards, Setsuna was the perfect choice.

As for his rather unconventional arrival here... such details were irrelevant—all it cared about was creating successors.

”Hiss...”

Everyone stared blankly at him.

”So what now? Are you like... the super-ultra Herrscher of Finality now?”

—

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