Crossover Shipgirls: Building a Dimensional Empire from Scratch

The projected starship caused quite a stir in Axel.

Adventurers all craned their necks, staring up at the colossal, futuristic vessel hovering above the city.

A ship larger than the entire town itself—the sheer pressure it exuded was overwhelming.

”W-what the hell is THAT?!”

Aqua, ever the airheaded goddess, trembled in fear.

She had only ever seen such terrifying machines in Earth’s science fiction works—and witnessing one in person made her realize how absurdly overpowered this was for this world.

”If we’re going to defeat the Demon King, taking a ship straight to his castle is the most efficient way,” Setsuna said matter-of-factly.

”What, did you expect me to act like some clueless newbie—go to the Adventurer’s Guild, accept boring frog- or slime-hunting quests to grind levels, slowly complete commissions to earn money for gear…”

”Then travel across the world step by step, struggle through endless hardships, fight countless Demon King generals, and finally face him in an epic final battle?”

”?”

”Isn’t… isn’t that the standard hero routine?” Aqua tilted her head, confused.

That was how all reincarnated heroes were supposed to do it—or so she thought.

Though, in her case, no one had ever actually completed the full journey. Most either wasted away in the starter village or died halfway when the Demon King’s army proved too strong.

”I’m here to solve a problem, not play house with the locals,” Setsuna said dryly.

”It’s fine to enjoy a bit of sightseeing once in a while, but when it’s business, I prefer efficiency.”

He waved his hand.

Shua—

The lower hatch of the battleship opened, and a small shuttle descended.

”Come on. We’ll deal with the Demon King first, then come back to recruit allies and handle the rest.”

Setsuna activated his scanners, surveying the planet’s geography.

He decided to take things one step at a time—defeat the Demon King first, then recruit the girls afterward.

”Hmm… the Demon King’s castle is a bit far from Axel, across some mountain ranges. But since we have a ship, that doesn’t matter.”

”Even with some minor detours, it won’t take long.”

”???”

Aqua was dumbfounded.

From the moment they arrived in this world, her jaw hadn’t once closed.

A reincarnated hero who, within half an hour of landing, was already preparing to fly straight to the Demon King’s castle.

Skipping every single traditional hero step—no recruiting companions, no leveling up, no gathering equipment.

What was this—speedrunning?!

And why was the order backwards?! Why was he fighting the Demon King first and recruiting allies later?!

”Ehhh?!”

For the first time in her divine life, the famously scatterbrained Aqua felt someone had out-crazied her.

She scratched her head, completely lost—and a little scared.

”No!!! The Demon King is really dangerous!!! I’m not going!!!”

”Setsuna, right?! How about we recruit some strong teammates first?!”

”I’m actually… not in that much of a hurry to return to Heaven…”

Aqua truly did want to go back—but she couldn’t shake the feeling that rushing to fight the Demon King was suicide.

After much thought, she decided to calm down this lunatic who wanted to charge straight into the final boss fight.

”?”

Bonk—

Setsuna smacked her lightly on the head again, then pointed toward Mio and Tohru.

”There’s no one in this world stronger than me or my teammates. Stop complaining. Get on the ship!”

...

Meanwhile—

Some distance away, in a noble’s mansion—

A silver-haired girl with short hair, dressed lightly and wrapped in a simple cloak, quietly climbed out through a window.

A faint scar marked her cheek. Though she was a girl, her slim figure was barely covered by a simple chest guard and shorts.

On her hands, she wore the standard gloves of a thief.

”Heh, too easy~”

The girl tied two pouches of stolen treasure from the noble’s room to her waist.

Even in broad daylight, with her skills, sneaking into an unguarded noble estate and looting ill-gotten treasures was child’s play.

The silver-haired girl darted and leapt across rooftops, quickly reaching a building that resembled a church.

Inside, many believers knelt as the priest led them in prayer before a statue of the goddess.

”Great Goddess Eris, may your blessings be upon both Heaven and Earth. Forgive our sins and grant us your protection in life…”

”Shield us from the monsters’ assaults, and may every adventurer return safely from their journeys…”

The worshippers’ voices were sincere, revealing their deep devotion to the goddess Eris.

The silver-haired thief leaned casually against the wall in a corner, listening to the prayer, and nodded in satisfaction.

A faint smile curved her lips.

”Mm, truly devoted followers…”

She lifted the two pouches of treasure she had taken from the noble’s mansion and placed them quietly at the entrance of the Eris Church.

Her movements were light—under her stealth skills, no one noticed a thing.

Once the prayers ended, the priest would soon discover this unexpected donation.

”Hehehe~ another good deed done~”

Having just helped her faithful, Chris was quite pleased.

She unfolded a piece of parchment, crossed out one of the targets, and scanned the remaining list.

”Hmm… there are still a few divine artifacts in Axel that need to be reclaimed. I’ll have to spend some time investigating…”

”Honestly, Lady Aqua’s always dropping cheat-tier relics everywhere—no wonder this world’s stability’s getting messy…”

The thief muttered to herself as she walked along the street.

Suddenly—

BOOM—

A massive ship was projected into the sky above.

”Huh???”

”What the—?!”

Chris froze, staring blankly at the enormous warship looming overhead.

She couldn’t make sense of it.

With her knowledge, she couldn’t identify what it was—but her instincts screamed that it was some kind of colossal weapon of war.

Judging by its sheer size, this was bad.

After her initial shock, Chris furrowed her brows.

She needed to figure out what this thing was, where it came from, and why it had appeared in this world.

As a hidden overseer, this was crucial information.

But the ship was far too large and high up. Even flight magic wouldn’t reach it.

Just as she was debating her next move—

Clank—

She saw a smaller shuttle descending from the battleship.

It seemed to be landing to pick someone up.

”Hmm? An opportunity?!”

Chris moved swiftly through the streets and alleyways.

Within moments, she reached the plaza where the shuttle had landed.

There, a blue-haired girl was arguing with a group of oddly dressed individuals.

”Setsuna, isn’t it way too soon to go fight the Demon King?! How about we train first?!”

”Heaven?! Sure, I want to go back—but if you die, I’ll be stuck here forever!”

”No, I’m going to find Eris! If you get killed, we’ll have to resurrect you somehow—”

”...?”

Chris blinked. That blue-haired girl looked suspiciously like her superior.

As for the others—judging by their appearance and behavior, they clearly weren’t from this world.

”Reincarnated heroes?” she guessed.

Their odd clothing fit the pattern perfectly.

”Oh, they must be Lady Aqua’s newest heroes! And they’re already planning to take on the Demon King?”

”But this is still the starter town… and what’s with that flying ship?!”

Chris’s curiosity grew.

Something about Setsuna’s group felt completely different from the usual heroes.

She focused her senses and noticed something strange.

”This aura…? A monster? No, higher level… a Demon King? No, not quite…”

She sensed faint traces of evil energy from the twin-tailed blonde girl in the group.

There was definitely a secret here.

Thinking for a moment, Chris decided to investigate personally.

Whoosh—

Activating her stealth skill again, she slipped through the edges of the plaza, unnoticed, and crept toward the shuttle.

Click—

The hatch seemed to respond to her presence, automatically opening to let her in.

”Eh? No security enchantments? Perfect.”

Chris grinned to herself.

”Waaah—”

After causing a scene on the ground, Aqua finally boarded the shuttle under Setsuna’s threat—if she didn’t, he’d leave her stranded in Axel.

She was terrified that if Setsuna somehow died, at least she’d be nearby to resurrect him. Besides, she was broke—being left behind meant starving to death.

”Commander, just now there was…”

Mio and Tohru tugged lightly at Setsuna’s sleeve, their gazes flicking toward a corner of the shuttle where some cargo was stacked.

There were faint signs of disturbance.

”I know. Shh—”

Setsuna smiled and gestured for silence.

He led the group aboard the shuttle and returned to the starship.

”Woooooah—”

The moment they stepped inside, Aqua was stunned once again.

It was enormous.

This wasn’t just a ship—it was a floating city.

The interstellar battleship’s size rivaled that of a surface metropolis. Even without its weapon modules, its interior offered vast living and operational space.

The group passed through long corridors and multiple compartments before reaching the command bridge.

A spacious chamber greeted them, lined with elegant, futuristic control panels. Holographic displays floated everywhere, showing streams of data across the walls. From any point on the ship, one could open a holographic interface and control various systems.

”Wooooow—”

Aqua was like a child on a school trip, touching everything she could find.

She peeked at the main console, pressing random buttons and curiously fiddling with different devices.

She’d never played with anything like this before—it was far too advanced.

Even after all her time in Heaven, none of the worlds she or the other goddesses managed had ever seen technology like this.

Aqua was completely fascinated by these strange new inventions.

”How does this thing even fly?” she asked.

”By using reactors and thrusters,” Setsuna replied.

”What’s a reactor? What’s a thruster?”

”A form of technology.”

”Can you explain it to me?”

”Alright. Let’s start with the basic principle of dark matter reactors…”

”...”

Aqua blinked blankly, her expression the picture of divine stupidity.

”When we get back to the Starsea Empire, I’ll have Chen Hai tutor you,” Setsuna sighed. ”You can sit with the little shipgirls.”

Explaining anything to Aqua was exhausting.

Her idiocy wasn’t the kind that came from being incapable of thought—it was that her brain operated on an alien logic, one that often led her to make baffling decisions.

He simply set her down in a seat and handed her a tablet.

”Sit tight, play with this, and behave. We’re heading out to defeat the Demon King.”

”Ohhh!”

Aqua immediately perked up. She had been intrigued by Setsuna’s tablet since their first meeting, and now she eagerly began playing with it.

Boom—

Setsuna tapped a few controls.

The starship’s thrusters roared to life, launching into the sky under the astonished gazes of Axel’s townspeople, vanishing beyond the horizon.

”Now then, one more thing…”

Setsuna sensed something aboard the ship.

He cleared his throat and looked toward the main control room’s door.

”Come out, stowaway. You came aboard the shuttle with us, didn’t you?”

”...”

No response.

Whoever it was, they doubled down on their concealment—using stealth magic and moving quietly to escape.

”Found out? No… he’s trying to trick me?” Chris thought, tiptoeing toward the exit.

Setsuna’s voice echoed again, calm but precise:

”Chris—or should I say, Eris?”

”Breaking into someone’s ship isn’t very polite. This vessel is a part of my body, after all.”

”Wha—?!”

The girl froze, shuddering slightly.

With a sheepish expression, she peeked out from behind the door.

”Uh, um… sorry about that.”

”And also, how do you know who I am?”

...

A few minutes later—

Aqua, Griseo, and Jingwei were all staring curiously at the girl before them.

Mio and Tohru, on the other hand, weren’t surprised at all—they had already noticed the uninvited guest who’d followed them aboard.

Chris’s outfit wasn’t much different from that of the locals—clearly the attire of a professional thief.

Her silver short hair, light armor, and short cloak gave her a bright, lively appearance.

”Two goddesses in one place, huh…” Setsuna chuckled. Though he quickly realized, Aqua and Eris didn’t recognize each other’s human forms.

”So then, Eris—what exactly were you sneaking onto my ship for?” he asked with a smile.

”Hmm? What did you just call her?” Aqua perked up from her tablet, ears twitching.

”Wait!! You’ve got the wrong person! My name’s Chris!” the girl stammered, frantically waving her hands.

”There’s no way someone like me could have anything to do with the great Goddess Eris! I’m just a humble thief-class adventurer!”

Stare—

Setsuna placed a hand on her shoulder and studied her quietly for a moment.

Then he pointed at Aqua.

”See this? That’s your superior, Aqua. She asked me to come save this world and defeat the Demon King—but I accidentally brought her along instead.”

”???”

”Lady Aqua?!” Chris blurted out before she could stop herself.

In Heaven, she had served as Aqua’s junior. The two got along well, and Chris—Eris—had always respected her deeply, often helping her handle her workload.

She had noticed earlier that the blue-haired girl looked awfully familiar but hadn’t dared to assume.

”???”

Aqua was completely dumbfounded.

”Wait, wait, Setsuna—what are you talking about?”

”This girl’s the one who stuffs her chest to trick believers? The one who lucked into becoming the Empire’s official goddess? The one who can’t even fight the Demon King without begging Heaven for backup?!”

”...”

”You’re just jealous of Eris, aren’t you?” Setsuna teased lightly.

...

A brief wave of chaos swept through the ship.

Under Setsuna’s probing and the shock of meeting Aqua in person, Chris finally confessed her identity.

”My apologies. I am Eris. In this world, I go by the name Chris.”

The girl lowered her head.

”It gets lonely in Heaven sometimes, so I occasionally descend to observe the world below.”

Eris was the goddess in charge of this world’s Heaven, presiding over fortune and luck. Her church had become the world’s dominant faith, and even the local currency was named after her.

To her followers, Eris was a gentle, kind, and deeply responsible goddess—highly beloved and respected.

”Huh? Then why’d you sneak aboard our ship?!” Aqua demanded, crossing her legs.

”This vessel’s sudden appearance caused quite a stir in Axel,” Eris explained softly. ”I wanted to investigate. Since I didn’t know who you were—and sensed a trace of malicious energy—I decided to observe first before revealing myself… but I ended up getting caught anyway.”

A little embarrassed, she touched the faint scar on her cheek.

Her eyes drifted toward Tohru.

”...”

”Tohru, looks like you can’t hide your villain aura anywhere,” Setsuna joked.

”???”

”How is that my fault?!” the dragon girl pouted.

It wasn’t her doing—the chaotic aura she carried was simply too strong for a heavenly goddess not to notice.

”Hmm…”

”So, Lady Aqua, what’s going on here exactly?” Eris asked, looking between Setsuna and Aqua.

”Well… it’s good you’re here,” Setsuna said, patting her shoulder. ”Saves me the trouble of finding you later.”

”Tohru will explain the details soon. For now, let’s just say—Aqua told me your world’s in trouble. We’re here to help you fix it.”

—

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