Crossover Shipgirls: Building a Dimensional Empire from Scratch

As the final step in proclaiming the official establishment of a civilization, the founding ceremony of the Starsea Alliance was naturally placed on the agenda.

At dawn, the sun rose slowly over the sea, casting its first rays across the azure ocean.

In the naval base square, the shipgirls and Bulins stood in formation, grouped in threes and fours.

They were uniformly dressed in black-and-red military uniforms, including the Bulins, who had donned black dresses.

Even though resources were scarce during this era of rebuilding, enough materials were scraped together to outfit everyone in new clothing.

Compared to their usual attire, these uniforms were more conservative. Yet, paired with the shipgirls’ natural beauty, they exuded an air of heroic elegance.

”Strange... just changing clothes makes everything feel different,”

Formidable muttered as she adjusted her sleeves.

The unified uniforms gave her an unfamiliar sense of belonging, a feeling that she was inherently part of this collective.

”Standardized uniforms are a key component of military discipline,”

Essex nodded in agreement.

As a weapon of war and a soldier by design, she strongly approved of Setsuna’s philosophy.

While the shipgirls at the port in their casual attire often resembled carefree wanderers, here, they felt like a cohesive unit.

Soon, Setsuna and Richelieu emerged from the base building, both dressed in the same black-and-red uniforms.

Setsuna’s tall, upright posture and youthful, handsome face gave him the appearance of a true general.

Compared to previous days, his demeanor had gained a resolute and decisive edge.

As the morning sun bathed him in its golden light, the shipgirls momentarily found themselves awestruck.

”This is our Commander...”

They stood in perfectly aligned formations, whispering no more.

Thus began the founding ceremony of the Starsea Alliance, along with the world’s very first flag-raising ceremony.

”Music, play!”

At Setsuna’s command, stirring and majestic military music filled the square.

This too had been a collaborative effort between Setsuna and several musically inclined shipgirls in the Vanguard Fleet.

Next, as the anthem played, a red flag adorned with a golden eagle was slowly hoisted up the flagpole, catching the first light of dawn as it fluttered at the highest point of the naval base.

”Today, the Starsea Alliance is officially established.”

Setsuna’s deep voice carried across the square.

Though there were only a few hundred individuals in attendance—shipgirls and Bulins included—and the scale was pitifully small for a civilization, this was still a meaningful beginning.

From this day forward, this place would no longer be a mere settlement or colony. It would stand as a civilization, poised to compete with others across the multiverse.

”We shall start from Earth, sail across the seas, and reach for the stars, planting the eagle flag in every world of the multiverse.”

”We will forge alliances with friendly worlds and crush any enemies who dare block our path.”

”Let our friends admire us, let our foes fear us, and let us build a civilization that spans the cosmos.”

”...”

Setsuna’s words were a proclamation of ambition and resolve, painting the vision of a colossal transdimensional super-civilization that existed vividly in his mind.

”Wow...”

The shipgirls’ hearts surged with excitement.

Formidable, Belfast, and others marveled at Setsuna’s commanding presence and leadership.

Though each fleet’s flagship oversaw far more shipgirls than he did, none had ever demonstrated such boldness and vision.

To journey into the stars and vie for dominion among the galaxies.

Although they were only at the starting line and far from being powerful, they were willing to lend their strength to help Setsuna realize this grand dream.

Taihou’s eyes, meanwhile, turned into literal hearts.

”Ah... Commander...”

”I knew I didn’t choose the wrong person...”

”No matter the world, no matter the battle, I’ll personally deliver victory to you...”

”Thank you. I look forward to your performance,” Setsuna replied with a nod toward Taihou.

”Ah~...”

The Sakura Empire carrier nearly swooned with joy.

Even Richelieu and Illustrious found themselves glancing sideways.

Unyielding determination, grand ambition—this was the type of Commander they were meant to follow as weapons of war.

”It feels like we’ll witness many different horizons in the future,”

the two shipgirls quietly commented to each other.

”Phew...”

After the ceremony concluded, Setsuna returned to his office in the naval base.

The fledgling nation faced countless challenges that demanded immediate attention.

The shipgirls, too, changed back into their casual attire and resumed their respective tasks.

Uniforms were reserved for expeditions and significant ceremonies, with everyday dress left to personal preference.

”That was an impressive show of resolve, Commander.”

Richelieu, now dressed in her usual elegant attire, casually swept her golden hair over her shoulder as she spoke.

Her gaze carried both admiration and a rare trace of tenderness.

”I feel less like a shipgirl of Azur Lane and more like a part of the Starsea Alliance.”

”That can’t do. Azur Lane is your home. We’ll still have to go back and deal with the Sirens.”

Setsuna laughed.

”Though, we could always consider annexing the harbor into the federation later on.”

”Such ambition!” Richelieu scoffed playfully.

”Why stop there? Why not invite the Sirens to join, too?”

”That’s not entirely out of the question,” Setsuna mused.

If the Sirens turned out to be intelligent and willing to negotiate, perhaps they could be allies instead.

Fighting endlessly with shipgirls over a single planet seemed pointless. Why not venture into other worlds together and face alien invaders instead?

With combined technologies, who knew what could be achieved? Perhaps even creating ”Abyssal Shipgirls”…

[Initial task completed. Issuing rewards…]

Just as Setsuna expected, not long after establishing the Starsea Alliance, the system notification chimed.

Indeed, founding a civilization required ceremony.

[Extracting technology tree…]

A kaleidoscope of images flickered before his eyes.

Setsuna hoped for an advanced technological or magical tree, preferably something high-end.

Drawing from a low-level world’s technology wouldn’t be of much use.

[Ding. Congratulations to the host for acquiring the technology tree: Mobile Suit Gundam.]

[Please strive to improve research capabilities and lead your civilization into the interstellar era.]

”What?!”

”Gundam?!”

Setsuna blinked, caught off guard. He had expected to draw something like Stellaris, Honkai, or Type-Moon technologies, which could fast-track his civilization’s entry into the space age.

But this reward was completely unexpected.

”Wait a second, which Gundam series are we talking about? Is it the one with Amuro Ray as the White Devil? Or Iron-Blooded Orphans?”

His lips twitched involuntarily.

These days, just mentioning Gundam evoked not only images of cool, awe-inspiring mechas but also memes like ”The streets are calm” or ”If we don’t stop walking, the road will never end,” accompanied by its iconic BGM Freesia/Uru—Blossoming Hope.

[The technology tree contains all Mobile Suit Gundam series technologies. Mastery will occur progressively, encompassing all scientific knowledge from the Gundam Universe.]

The system’s response was succinct.

Thud.

A heap of blueprints and design documents landed in his storage space.

Setsuna casually pulled one out—a nearly half-human-height encyclopedia.

The first page featured a relatively simple-looking mech:

Mass-Production Model: Zaku MS-05 Type

• Prerequisite Technology: None.

• Description: A combat machine made of steel alloy. As a mass-produced model, it is not particularly powerful but is cost-effective.

• Weapon Systems:

• 105mm Machine Gun ×2

• 280mm Rocket Launcher ×1

• Heat Axe ×1

• Weight: 72.5 tons

• Thrust Power: 47,000 kg

This was the mass-produced cannon-fodder unit in the Gundam series, with unimpressive stats and a disposable role on the battlefield.

The blueprint not only detailed the specs but also provided step-by-step manufacturing instructions and foundational theoretical knowledge.

Although Setsuna wasn’t a physicist, he could tell the information was extremely comprehensive—practically a how-to guide. By following the instructions, creating a prototype would be relatively straightforward.

He picked up another book:

Mass-Production Model: Zaku II

• Prerequisite Technology: Zaku MS-05 Type

• Description: An upgraded version of the MS-05 Zaku. Its primary weapon has been replaced with a large-caliber machine gun, improving both firepower and mobility.

• Weapon Systems:

• 120mm Machine Gun ×2

• 280mm Rocket Launcher ×1

• Heat Axe ×1

Creating advanced models required the foundational units as prerequisites, akin to unlocking a skill tree in a video game. Without the appropriate knowledge base, one wouldn’t understand the principles behind more sophisticated designs.

…

In addition to mass-produced Zakus, the technology tree included a variety of legendary Gundams:

• ASW-G-08

• Barbatos

• RX-0 Unicorn

• ZGMF-X20A Strike Freedom

• Turn A Gundam—∀ (Moonlight Butterfly)

Each model was an icon in its respective series.

This reward essentially handed Setsuna the entire technological framework of the Gundam Universe.

”Wow…”

Setsuna combed through the tech tree, thoroughly engrossed.

Although integrating with the Wisdom Cubes had granted him a body comparable to shipgirls, lacking a rigging system made him feel incomplete.

If danger struck, he’d be left to rely solely on hand-to-hand combat. The port’s equipment wasn’t tailored for him either.

This new technology tree solved that problem.

Real men pilot Gundams to tear apart aliens. Who could resist the allure of piloting a Gundam?

”Commander?”

Richelieu, noticing his prolonged silence, approached curiously.

”What are you looking at?”

”Call Akashi over.”

Setsuna’s voice carried a distinct weight.

”I want to pilot a Gundam.”

Ten minutes later…

Akashi, who had been leisurely slacking off, was dragged into the office.

”Commander, are you finally going to return the Wisdom Cubes, meow?”

”When are we heading to other worlds to sell those painted loot boxes?”

The cat-like ears shipgirl blinked in confusion as she alternated glances between Setsuna and Richelieu.

”Forget about the loot boxes for now. I need to ask you something.”

Setsuna gestured for Akashi to sit and pulled out a blueprint.

”Can you understand this Zaku design?”

”Hmm?”

Scratching her head, Akashi tilted her ears while studying the diagrams.

”This is… a big robot?”

”And there’s even a cockpit for a human pilot? A combat machine operated by humans?”

As a repair shipgirl, Akashi had a solid engineering foundation.

While this technology was from another world, she could grasp the core concept behind a Gundam.

”The weapon systems are simple enough. A 105mm machine gun and rocket launcher could be made in the naval base’s arms factory. Steel alloy materials don’t seem overly complex either—just need more ore to refine…”

”The propulsion system seems a bit tricky. The engines from planes wouldn’t suffice; we might need to adapt the power systems of carriers or battleships instead…”

After studying the diagrams for a while, Akashi nodded.

”It should be doable.”

”What about the advanced models?”

Setsuna produced blueprints for upgraded Gundams.

He wasn’t particularly interested in mass-production Zakus—they might not even match up against destroyer-class shipgirls. If there was ever an army, they could handle those.

What truly mattered were the one-of-a-kind hero-class Gundams in the series.

”Hmm…”

Akashi buried herself in a towering stack of diagrams, flipping through them page by page, her brows furrowed.

”This is… hard, meow…”

”What’s a beam magnum rifle, a psycho-frame, floating shields, or field generator? I’ve never seen any of this before, meow…”

The diagram in question depicted the RX-0 Unicorn, a towering 20-meter Gundam equipped with a large-scale particle rifle and shield. It hailed from the Mobile Suit Gundam UC series, boasting extreme mobility and the ability to transform into its Destroy Mode.

”Any obstacles?”

Setsuna asked.

”This thing’s blueprint alone is thousands of pages long, meow. It’ll take forever to figure out, and it requires loads of refined ore—we might not even have enough in storage…”

Akashi neither outright refused nor agreed; she simply expressed that the task was extremely complex.

After all, this was technology from another universe.

Though the provided documentation was comprehensive enough to study, it required effort to decipher.

”So it’s possible, huh?”

”Great.”

Setsuna patted Akashi on the head. Her ears twitched at the unexpected softness.

”From today onward, you’re the Chief Scientist and Engineering Director of the Starsea Alliance, in charge of researching technologies I bring back from other worlds.”

”Our first goal? Build me a Unicorn or a Strike Freedom Gundam.”

”Meow?!?”

Akashi’s ears perked up as her brain scrambled to process the declaration.

”Meow meow meow meow meow?!”