Crossover Shipgirls: Building a Dimensional Empire from Scratch

The group moved onward.

Under Mash's guidance, they quickly located a site where leylines converged. Setsuna could faintly sense the magical energy diffusing in the area.

"We'll summon a Servant here," Mash said, taking materials from her backpack to draw a summoning circle on the ground.

"To summon a Servant, we usually need a relic as a catalyst, but unfortunately, we don't have any."

"In that case, we'll just have to take our chances and see if we can summon someone from this era…" Ritsuka Fujimaru muttered as she rummaged through her bag.

Having only recently joined Chaldea, she didn't have much to her name and had already been saddled with the monumental task of saving humanity.

"I might have a relic," Setsuna said as he materialized part of the interior of his Gundam. He rummaged around for a moment before pulling out a rusted, broken sword, its blade snapped in half.

"What's that?"

Both the shipgirls and Fujimaru looked puzzled as they eyed the ruined weapon.

"The Sword in the Stone," Setsuna replied casually. "It's supposed to be a relic of the King of Knights."

"!!?"

"The Sword in the Stone?! Are you serious? Where did you even get this?!" Mash exclaimed, stepping closer to inspect the artifact. The worn-down blade indeed appeared ancient.

"I found it in the Demon Slayer world. Not entirely sure if it's genuine," Setsuna admitted.

"It came with a shipment of tribute materials. Ning Hai mentioned that when she visited the British Museum, they handed over some historical artifacts as part of their offerings."

Setsuna thought back to the bizarre assortment of items the Bulin fleet had brought back. Alongside strategic resources like coal, iron, and steel, they'd also delivered wine, spices, artwork, tiger-skin skirts, and random historical relics.

"She thought it might make a decent decoration, so she brought some back."

"..."

The shipgirls exchanged looks, utterly astonished.

A person from the Starsea Alliance was about to summon a Servant in the Nasuverse using a relic excavated from the Demon Slayer world.

Could this even work?! It was crossing through three entirely separate worlds!

"Who cares? A King of Knights is a King of Knights. Legends are legends, and their histories are more or less the same," Setsuna said, shrugging.

"It's better than nothing."

He placed the broken sword in the summoning circle and, following the instructions from the texts, began reciting the incantation.

"Thy body shall be under my command, and my fate shall be with thy blade…"

"Answer the call of the Holy Grail! Abide by this will and heed my words!"

"I am the one who embodies all virtues of this world. I am the one who stands against all evils of this world…"

As he chanted, the summoning circle began to glow, its radiance growing brighter with each word. The Sword in the Stone trembled faintly within the light.

"Will it work?"

The group gathered around, holding their breaths.

"..."

"Thou art bound to the three great words of power, descending here as a guardian of balance…"

"Manifest before me, Protector of the Scales!"

As the incantation concluded, the summoning circle erupted with golden light.

Boom—

A shockwave blasted outward, kicking up a whirlwind of dust around them.

Cough—Cough—

As the dust cleared, a blonde-haired, blue-eyed girl with a strikingly beautiful face stood in the summoning circle. She was dressed in a blue formal dress and a partial suit of armor. Her hands rested firmly on the hilt of a holy sword, her gaze sharp and resolute, with a single strand of hair sticking up prominently on her head.

The poster girl of the Nasuverse—Artoria Pendragon.

The girl looked at Setsuna and spoke in a steady voice:

"Servant, Saber. I have answered your summons."

"I ask of you: Are you my Master?"

"!!!"

"Is this even possible?!" Ritsuka and Mash felt their worldview shatter. This man had pulled out some random artifact and actually summoned a legitimate Servant?!

And why did she look so familiar? Was this the original version of the blackened Saber Alter from the Fuyuki singularity?

"When we get back, tell Ning Hai to have all the countries hand over their museum artifacts. From now on, they can pay taxes with relics," Setsuna mused, feeling as if he had just opened the door to a new world. The prospect of an army of Servants felt tantalizingly close.

"Master? What is this place?"

The ahoge-topped knight looked puzzled by her surroundings.

The last time she remembered being summoned, it had been during the Fourth Holy Grail War in Fuyuki City—modern times. How was she now in the medieval era? Were Holy Grail Wars even held during the age of cold steel?!

"Weren't you infused with knowledge about the current world?" Ritsuka asked curiously. Typically, when a Servant answered a summoning, they would automatically receive basic information about the world they were summoned into.

"No, and the magical energy I feel in my body is quite peculiar..."

Artoria extended a hand and examined it.

A Servant required their Master's magical energy to exist in the present world. She could sense the connection between herself and Setsuna, establishing their Master-Servant relationship, but he wasn't a mage. The energy he provided wasn't conventional magical energy—it was something strange and chaotic, making her feel slightly unsettled.

"It's the power of a Wisdom Cube. Make do with it for now. I'll research the Nasuverse's mana system later," Setsuna said, patting Artoria reassuringly.

He noticed three Command Seals appearing on the back of his right hand. Red and shaped like a shield, their design resembled Ritsuka's, though their exact function remained unclear.

Normally, only official Masters participating in a Holy Grail War could receive Command Seals, bestowed by the Greater Grail to bind and empower Servants. Yet, his body's compatibility had proven remarkable once again. Not only could he summon Servants, but even the accompanying perks appeared.

"Why is King Arthur a cute girl?" Formidable asked, finding the knight before her vastly different from the Arthurian image she had in her mind.

"The Nasuverse is just like that. Don't get hung up on the details," Setsuna said, motioning for the shipgirls to remain calm.

"..."

Ritsuka stared at Setsuna and Artoria, her expression hesitant.

"I just thought of something."

"Go ahead."

"The place we're in right now… It's 1431 France, right? And we're in the middle of the Hundred Years' War with England?"

"Correct."

Setsuna nodded.

The Hundred Years' War had left France and England as sworn enemies for centuries. The two nations remained antagonistic well into modern times, often exchanging jabs. Joan of Arc had died fighting to repel the English, and the war's intensity was at its peak, with both sides determined to obliterate the other.

"And who did you summon as your Servant?"

"Artoria Pendragon—the Knight King of Britain."

"..."

The group exchanged incredulous glances.

"You summoned the British Knight King in the middle of the Hundred Years' War, on French soil," Ritsuka said after a pause.

"Servants manifesting in the real world generate intense energy fluctuations. It won't take long for others to notice the anomaly here."

"Before we get swarmed and beaten to a pulp, may I humbly ask: Did you come here just to pick a fight?"

"Don't panic!"

"If things go south, I can always open a portal and summon some Ironblood shipgirls for a bit of bloodline suppression over France."

Setsuna tried to ease the worried expressions on Ritsuka and Mash's faces. As a backup plan, he could call reinforcements from either his base or home world if necessary.

"…"

Richelieu frowned slightly at the term "bloodline suppression," vowing to challenge Bismarck for a sparring match later to change her Commander's misconceptions.

Meanwhile, Setsuna spread a map across a rock, marking two locations with a pen.

"Now, let's focus on how to solve this singularity."

"We're near Dijon. Based on my memory, the boss of this singularity—Black Jeanne and Caster Gilles—should be in Orléans. The Greater Grail is there as well."

"The distance… about 200 kilometers. Not too far."

Since they were in the inland region without rivers, the shipgirls couldn't deploy in their ship forms for this journey.

"Should we launch an airstrike on Orléans directly?"

Taihou and Formidable released reconnaissance planes to scout the area, their aircraft circling overhead.

"No need. That would alert the enemy prematurely, and berserk Servants aren't as weak as that chicken Muzan. An airstrike alone won't cut it," Setsuna replied, shaking his head.

"Then are we walking there?"

"Hmm, let's get moving quickly. If we hurry, we can reach the next city by nightfall and buy some supplies…" Mash immediately began plotting a route.

"Who said we're walking?"

"Hop on. We're going to blitz France with a Gundam and give them a taste of mechanized shock and awe."

As soon as he finished speaking—

Ka-chunk—Ka-chunk—

Setsuna projected the frame of Strike Freedom.

Thanks to his fusion with the machine, he could summon any part of Strike Freedom's frame at any time and place.

As the towering Gundam materialized before them, Mash and Artoria stared in stunned silence.

"What is this? A giant robot?"

Ritsuka Fujimaru, having seen modern technology before, offered her guess:

"It's a Transformer!"

"…"

"You're going to give someone high blood pressure like this… It's called a Gundam. Specifically, Strike Freedom."

"I'll introduce you to the Autobots later," Setsuna sighed, exasperated by the somewhat scatterbrained girl.

He operated the mech to kneel and extend its massive hand, inviting everyone to climb aboard.

Strike Freedom, designed for atmospheric and orbital flight, could achieve speeds several times the speed of sound at full thrust. Even at subsonic cruise speed, the 200-kilometer journey would be over in a flash.

"Master, why does your style feel so… out of place compared to everyone else?"

Artoria glanced around, her thoughts conflicted.

It was the height of the Middle Ages in 1431. French knights were clashing with English longbowmen.

In an era where sieges relied on catapults, crossbows, and swords, someone had shown up piloting a Gundam.

How strange.

…

Hum—

At an altitude of several thousand meters, Strike Freedom spread its DRAGOON wings, cruising subsonically through the atmosphere.

The mech was designed for a single pilot and had no additional seating. As a result, the eight-person group had to squeeze together inside the cockpit.

Richelieu, Formidable, and Artoria squeezed into the space on the right side of the cockpit.

The two shipgirls flanked Artoria, leaving her sandwiched in the middle.

"Ugh, so heavy."

Artoria felt something pressing down on her head. Looking up, she realized what it was: Richelieu on one side, Formidable on the other.

Despite wearing uniforms, the shipgirls' impressive sizes were undeniable, especially for a battleship and an aircraft carrier.

"…"

Artoria lowered her gaze, glancing at herself, feeling an inexplicable wave of inadequacy.

How odd. They only seemed slightly older than her, so why was the difference so stark?

It had to be the fault of Excalibur. Pulling it out must have halted her growth. Yes, that must be it.

On the left side of the cockpit, Jeanne d'Arc, Ritsuka Fujimaru, and Mash shared the space.

Since all three were relatively petite, they had more room to move around.

"Whoa, whoa, whoa—"

Ritsuka was beside herself with excitement, experiencing a Gundam ride for the first time.

She couldn't stop twisting around, staring out the observation window at the clouds and the earth below.

"So other worlds have toys like this?! Can I get one too?!"

"Mash, I don't want to be a Master anymore—I want to pilot a Gundam!!!"

"???"

The shield-wielding Demi-Servant was utterly flabbergasted.

"We still have to save humanity!!! Dr. Roman is waiting for us back in Chaldea!"

Inside the cockpit, with both sides packed full of people, Setsuna was left sharing the central seat with Taihou.

From behind him came a peculiar sensation.

"Commander-sama…"

Taihou leaned in close, her subtle fragrance wafting over him.

"Uh, I'm piloting a Gundam here—please go easy on me…"

Setsuna tried to keep his focus.

"Commander, why won't you take a proper look at Taihou?"

Suddenly, her voice softened with a hint of yandere.

"Do you already have someone you like?"

"I like all the shipgirls in the port."

Setsuna felt like Taihou was asking him a loaded question.

"If that's the case… then why won't you spend more time looking at Taihou? Do you not like me?"

"Taihou would give you anything, if only you'd ask…"

Taihou rested her chin on Setsuna's shoulder, whispering close to his ear.

Her tone was sultry, tinged with faint sorrow, making his spine tingle.

"Good grief—who can resist this?!"

Setsuna shuddered.

Reflecting on his journey—from his initial start, to meeting the shipgirls, and beginning the construction of his settlement—he quickly launched into a self-assessment.

"I used to be so focused on development and expansion that I overlooked your feelings."

"I'm sorry."

Ever since being thrown naked onto Earth, Setsuna had spent most of his time dealing with bizarre challenges.

From building a colony from scratch, coordinating the base's industries, to subjugating natives from other worlds to secure resources—most of his attention was on ensuring the base thrived.

In the process, he often overlooked the individuals involved.

But now that things were stabilizing, he didn't need to stay on edge all the time.

"Then… do you like Taihou?"

Her voice carried a faint tremor.

"Yeah."

Setsuna nodded.

Who could resist a shipgirl's direct confession? Especially when they were squeezed so close together.

"Commander-sama!!!"

Taihou's excitement was palpable, and Setsuna could feel her hands wandering.

"Uh, don't you think it's a little cramped here? Maybe we should wait until we're back and find somewhere with a better atmosphere?"

He suggested, realizing how tight the cockpit was. It was hard to even turn around, let alone move freely.

"That's true. We wouldn't want any pests to see."

Taihou paused for a moment, her hands still restless.

"But… I'd like to get to know you better, Commander…"

"For example…"

"???"

As Setsuna's mind began to wander, he was abruptly interrupted by Richelieu and Formidable shouting:

"Commander! A dragon! A dragon! A DRAGON!!!"

"There's a dragon ahead!!!!"

"Quick, dodge!!!"

"Ahhhhh—"

"What?!"

ROAR—

A thunderous dragon's roar echoed from the distant sky.

A massive black dragon, much larger than Strike Freedom, was circling above a city. It unleashed fiery breath, reducing the city below to a blazing inferno.

"What the hell?! Where did a dragon come from?!"

Before Setsuna could react, the Gundam, cruising at subsonic speed, slammed directly into the dragon.

"Oh crap, crap, crap—"

BOOM—

The outer armor of Strike Freedom was immensely durable, but so were the dragon's scales.

The collision produced a deafening impact.

And then—

Entangled in a bizarre mid-air struggle, the Gundam and the dragon spiraled down together, crashing into the ground with an earth-shattering impact that left a massive crater in their path. Dust and debris exploded outward, momentarily obscuring the chaotic scene.