Crossover Shipgirls: Building a Dimensional Empire from Scratch

Starting a civilization from scratch is challenging, but once a foundation is laid, its development accelerates at a geometric pace.

A month quietly passed. Spring rains gently drizzled, transforming the forests outside the city into lush greenery.

In the agricultural zone, the Bulins and the small yellow chicks had begun a new cycle of farming.

Although the city had few ordinary inhabitants, and apart from Artoria, shipgirls and Heroic Spirits didn’t consume much food, stocking up was a habit ingrained in Setsuna’s DNA. It also improved their meals.

Beyond the capital’s coastline, fleets of Bulins transported resources from all over the world. In addition, small groups of Siren units patrolled the waters.

The Sirens, particularly those of the Executor class, possessed some degree of self-awareness. However, their thoughts were still influenced by higher-level Sirens like Purifier and Compiler.

After some time together, the smaller shipgirls and the Bulins had grown accustomed to these peculiar allies.

Though mostly silent and reserved, they exhibited no ill intent and typically stayed near the Siren naval base. Occasionally, they wandered into the capital for leisure.

Purifier, however, was the exception—carefree and completely unbothered about her Siren identity, spending her days playfully mingling with the Commander, Heroic Spirits, and other shipgirls.

”Ohhhhhhh—Kanna, slow down!!”

In the skies, a small white dragon could occasionally be seen flying among the clouds, carrying several destroyers on its back.

The young dragon girl from the Dragon Maid world had developed a close bond with the destroyers.

Not only did they attend school together, but Kanna often transformed into her dragon form to take the smaller shipgirls on flights.

Given the base’s diversity, which ranged from magical creatures to mechanical lifeforms and mythological entities, the appearance of a dragon caused little surprise.

Inside the administrative center, Setsuna, taking advantage of downtime from starship modifications, casually opened the statistics interface.

[Civilization Overview]

• Civilization Type: Technological Civilization

• Technological Level: Space Age (Sub-light Speed)

• Population: 673,255

• Species: Humans, Shipgirls, Sirens, Heroic Spirits, Dragons

• Territorial Control: 36.376 million square kilometers

From the 300 pioneers of the initial fleet, the population had surged by over 2,000 times, exceeding 600,000.

With Bulins manufacturing other Bulins in an infinite self-replicating cycle, the base numbers increased exponentially, leading to ever-increasing production efficiency.

Among them were tens of thousands of Sirens, some built by the Bulins, others assembled by Compiler.

The Executor-class Sirens were essentially military-grade Bulins. They patrolled the seas near Constantinople, escorting the Bulin fleets.

However, with no enemies left on Earth, most Siren duties consisted of mundane tasks, like using naval cannons to ward off corn-stealing bears, or firing torpedoes at sharks to protect fisheries.

The bulk of their work revolved around such trivial, monotonous tasks.

”Hmm… I like the Bulins.”

Setsuna decided to further bolster the Bulin Fusion Plan in the future.

Not only were the Bulins adorable, but they were also the embodiment of productivity.

The versatile Bulins could farm, build structures, repair ships, and manufacture Wisdom Cubes, functioning as foundational workers.

The more advanced prototype and specialized Bulins were capable of high-tech production, such as constructing starships and wonders.

In Stellaris terms, they could even qualify as technological specialists.

His dominion now spanned over 36.37 million square kilometers, slightly less than the total area of the Asian continent.

Part of this expansion came from the Bulins establishing mines and offshore drilling platforms worldwide, incorporating those areas into the territory.

Another part was due to the Azur Lane world being fully under his control.

Both the ports and Sirens had relocated, and portions of the ocean and land there now counted as his territory.

However, Setsuna believed that as time went on and his influence grew, the way he measured his dominion would also change.

From the mere 60 square meters he had started with, he would soon shift from counting in square kilometers to entire planets, star systems, galaxies, or even entire universes.

He casually tapped on the species encyclopedia.

[Sirens:]

[Also known as Index. In a sense, they share origins with the shipgirls, both being technological lifeforms specialized in naval warfare. Lower-ranked Sirens are subject to the control of higher-ranked Sirens.]

[They possess an extensive organizational structure, divided into the Tribunal and the Terminal. However, the Tribunal in this universe has gone out of contact.]

The description matched what he already knew.

The Siren technology was even more advanced than Azur Lane’s, though the Compiler, who oversaw their research, was frustratingly aloof.

She stayed holed up in the Siren naval base, unwilling to engage much, leaving Setsuna pondering ways to grow closer to her.

”Wait a second.”

As he browsed, a thought suddenly struck him.

”Where’s Yat Sen?”

The last time they talked, she neither agreed nor refused him. Instead, they had continued interacting as usual.

Recently, however, he hadn’t seen her much.

Their encounters were limited to brief moments when she came to deliver documents.

It puzzled him—he had no idea what she was thinking.

”Do you know where Yat Sen is?”

He turned to Richelieu and Taihou.

”Her? Hmm… I think I heard the other Dragon Empery shipgirls mention that Yat Sen’s been busy with her own affairs recently?”

Richelieu replied uncertainly.

”Should I call her over?”

”Never mind. I’ll go find her myself.”

…

…

By evening, after finishing his work for the day, Setsuna headed toward the dormitory area near the Azur Lane naval base.

Most of the shipgirls were unfazed by his appearance, greeting him with playful laughter.

”Commander, are you here for Taihou or Richelieu today?”

As long as he didn’t intrude on other shipgirls’ private rooms, they didn’t mind the commander wandering around this area.

Before long, after asking two Dragon Empery shipgirls, Setsuna arrived at Yat Sen’s door.

Knock, knock, knock—

When the door opened, he was greeted by Yat Sen’s startled expression.

”Com… Commander? What brings you here?!”

She was dressed in a white ruqun with a short hem that subtly revealed her thighs, paired with white stockings, exuding a graceful yet alluring charm. Even though she lived alone in this room, she had carefully dressed, her hair elegantly styled into intricate buns that cascaded naturally over her shoulders.

”Came to see you. It’s been a while, and I was wondering what you’ve been up to.”

Setsuna smiled as he glanced around the room.

The decor was dominated by dark wooden furniture, with ink-wash landscape paintings hanging on the walls. A few screens partitioned the bedroom from the living area. The arrangement was exquisite, elegant, and dignified—classical Dragon Empery style. Each faction’s shipgirls had their unique preferences for interior design.

”Ah… You should’ve told me earlier so I could prepare…”

Yat Sen appeared flustered as she invited Setsuna inside. She poured tea, set out some snacks, her face flushed with a rosy hue.

”What have you been busy with lately? Ever since we got back, you’ve been practically invisible. Is it because you felt awkward about rejecting me and decided to avoid me? It’s fine, I don’t mind.”

Setsuna began, taking a direct approach in dealing with shipgirls.

”Even if you don’t accept me for now, it’s okay—”

”No… it’s not that…”

Yat Sen lowered her head as though she was carefully choosing her words.

”I didn’t mean to reject you… I just… need some time to prepare…”

”Prepare? Prepare what?”

Setsuna was puzzled. Shipgirls didn’t need dowries or any such things.

”Uh…”

Yat Sen covered her face, intentionally leaning to the side as if trying to block something from view.

”Hm?”

Setsuna moved around to take a look. On the chair behind her lay an ornate red dress.

The dress was intricately made, with fine materials and gold-thread embroidery decorating its edges and hem.

It was more than halfway finished, with a sewing kit and other textile tools placed nearby.

”This is…”

No matter how he looked at it, it resembled Yat Sen’s oath attire: the phoenix coronet and embroidered robes.

”Ah… I was thinking… if I’m going to become your oath-bound ship someday, I should prepare the outfit in advance…”

Yat Sen mumbled hesitantly.

”You’ve been making this by yourself for so long? Wouldn’t it be faster to let the Bulins handle it?”

Setsuna was momentarily stunned by what he saw.

”Commander, something like this has to be made by oneself for it to hold meaning.”

Yat Sen stood up with a touch of playful reproach, lightly pressing her finger against his chest. As an Dragon Empery shipgirl, she had a deep-seated sense of ceremony about certain things. The most important outfit, naturally, had to be sewn by her own hands.

”…”

Setsuna was instantly moved.

The shipgirl had even prepared her wedding attire—how could he not seize the moment?! He pulled Yat Sen into an embrace, gently stroking her long hair.

”Eh?! Commander?”

Yat Sen symbolically tried to wiggle free but soon leaned softly against his chest. A warm and fragrant sensation filled the air. Her figure was tall by shipgirl standards, but compared to Richelieu or Taihou, she was slightly more petite, giving her a delicate and dependent air.

”Thank you.”

”But some things don’t need this much preparation; just one word is enough.”

Setsuna lightly patted Yat Sen.

”You took so long to respond that I thought I’d made you angry.”

”…”

”How could that be…”

The once composed and serious flagship of the Dragon Empery was now blushing furiously, burying her face deeper and deeper into his chest.

”I just wanted to surprise you… but you came too soon…”

Her voice grew quieter and quieter until it was barely audible.

”Then this means you agree?”

Setsuna lowered his head, locking eyes with Yat Sen.

”Mm…”

The girl gently nodded, then stood on her tiptoes, leaning in closer.

”From now on, Yat Sen will always stay by your side.”

…

A faint scent of plum blossoms lingered on his lips.

Compared to the romantic Richelieu and the fiery Taihou, Yat Sen possessed a more reserved elegance unique to Dragon Empery shipgirls.

”Hmm?”

Perhaps sensing Setsuna’s subtle reaction, Yat Sen’s expression turned slightly uneasy.

”Uh, if this makes you uncomfortable, we can wait until later.”

Setsuna thought about it and decided to respect the shipgirl’s wishes. It was understandable for an Dragon Empery shipgirl to lean towards tradition. He was willing to wait—for the promise ring, for all the arrangements to be in place.

Together, they could hold an oath ceremony in the Dragon Empery style, just as Yat Sen envisioned.

”It’s all right, Commander,” Yat Sen softly whispered.

”Please… be gentle…”

…

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