Crossover Shipgirls: Building a Dimensional Empire from Scratch

”Uh... I think when the Sage designed this tower, he definitely didn’t anticipate this kind of strategy.”

Inside the Pleiades Watchtower, the Konosuba Squad made a raucous ascent upward.

The interior was a mess—some areas were even warped by spatial distortion.

According to the original storyline, those who entered the Pleiades Watchtower were supposed to face the Sage’s trials on each floor.

There were puzzles involving giant stone riddles, tests to draw a chosen sword, and even battles against the first-generation Sword Saint, Reid Astrea.

But after being bombarded by multiple nuclear-level Explosion spells, most of the magic mechanisms that powered the trials had been completely obliterated. The Pleiades Watchtower now revealed its true form.

It was an enormous spiral structure, with vast, minimalistic floors. Faint traces of leaking mana could be felt throughout.

All those rooms and trial spaces had originally been created through spatial and cognitive interference magic. Normally, when challengers entered the tower, these mechanisms would activate and teleport them into the appropriate trial space.

But now, with all systems destroyed, nothing functioned properly. The group encountered almost no resistance as they ascended.

”...”

”As expected, people from the Konosuba world really are insane...” Senti muttered to herself.

Before long, after passing through the ruins of the third floor, the group arrived in a large, unfamiliar library.

The room was structured in concentric circular steps. The group stood in the lowest center area, while the outer rings rose higher. All around them were tightly packed bookshelves filled with countless tomes—enough to rival one of the Imperial Capital’s largest libraries.

”Whoa, whoa, whoa! So this is the Great Sage’s Library?!” Megumin and Yunyun instantly perked up.

The Crimson Demon lolis scattered, hopping and running excitedly among the towering shelves.

”Hmm... what’s this...”

Senti and Iris each pulled a random book from a shelf. The title looked like a person’s name—one they didn’t recognize.

After searching further, they found names they did know.

Reid Astrea, Petelgeuse Romanée-Conti, Regulus Corneas...

The Sword Saint, and even several of the Archbishops of Sin, all had books here.

Iris opened the book with Reid Astrea’s name on it.

Instantly—

She was pulled into a vision.

Scenes of his life flashed before her eyes like a lantern show.

From his miraculous childhood, inheriting the Sword Saint’s blessing, joining the Royal Guard...

To being chosen by the Sage Council to face the undead legions led by the Great Tomb, being sealed into the Depiction of Nature and Society Scroll, dueling Shalltear, and finally perishing together with her under Longious.

The images were vivid—so real it felt like she had personally witnessed the battle with Shalltear.

Especially that final, world-shattering strike from Longious—it left a deep impression.

”Whoa—”

When it ended, Iris rubbed her temples, her head aching.

Meanwhile, Senti flipped through the book of Sloth.

It contained the entire life of Petelgeuse, from his days before madness—when his memories were altered by the Witch of Vanity—to his eventual defeat at the hands of the Great Tomb Squad.

”So these are... the Books of the Dead?” Iris recalled after thinking for a moment.

Every deceased person in the Re:Zero world had their life recorded here.

Not only ordinary people and the Archbishops of Sin—but even the Witches of Sin themselves had volumes here.

Pride: Typhon. Wrath: Minerva. Lust: Carmilla... and more.

Only one was missing—the Witch of Envy, Satella.

She hadn’t died, merely sealed away by the Three Heroes.

”Oh, so that means... this place contains the entire life stories of everyone in this world?”

Megumin scratched her head.

This ”knowledge of the Great Sage” wasn’t quite what she had expected.

”Sounds kind of amazing though. I’d like to have my life written in a book too—so everyone could see my glorious achievements! ...Though, I don’t actually want to die yet...”

”What’s the point of these books anyway? Just to gossip about the dead? And weren’t they supposed to only be readable by those connected to the person written inside?”

The lolis whispered among themselves.

”Maybe... we just don’t fall under the Sage’s rules?”

Iris clapped her hands, pulling the Crimson Demon lolis—who were completely absorbed in the illusion—back to reality.

”Alright, enough. Let’s just consider these our spoils of war. Pack them up and call the Commander.”

”How these books will be used later, we’ll let the Commander and the Magic Academy decide.”

The group swept through the rest of the tower.

Aside from the Books of the Dead, they also found several prophetic tomes and spellbooks left behind by the Great Sage—all written in the ancient Re:Zero language, encrypted with bizarre magical ciphers.

The Konosuba Squad couldn’t be bothered to translate them one by one, so they simply packed everything up to hand over to the Magic Academy and the Imperial Grand Library for preservation and decoding.

After all, the library had a certain dragon lady who was obsessed with foreign-world artifacts—she’d definitely be thrilled to see something like the Books of the Dead.

”Hmm...”

After ransacking the Great Sage’s library, the group—still noisy as ever—continued their advance.

”Let’s see... the second floor was supposed to be guarded by Reid Astrea, but that space already got blown up earlier, so we can just move on...”

”And the first floor should be where the Divine Dragon Volcanica is.”

As Iris gathered the team—

Suddenly—

At the top of the staircase appeared a small, filthy boy with long, tangled brown hair hanging to his knees.

He wore tattered clothes, and his exposed limbs were caked with grime. In one hand, he clutched a short sword. His posture was hunched, and his eyes gleamed with a greedy, deranged hunger as he scanned the Konosuba Squad.

”Tsk, tsk, tsk, tsk, tsk...”

”Delicacies! Delicious, delicious food! More delicious than anyone else!!!”

He scratched at his head, his tongue flicking as he spoke in a stuttering frenzy.

”This banquet within the Tower... we’ll devour it all!”

”So good, so good, so very good—of course it’s good, obviously good, isn’t it? Yes, yes! Feast! Feast!”

”Tsk, tsk, tsk...”

”?”

The Konosuba Squad froze for a second, staring at the raving lunatic.

”Wait... that’s one of the Archbishops of Sin—Gluttony, isn’t it?”

”Why is he here?!”

”Of course! It’s because of you—you’re all so delicious!! Ah... the exquisite flavor of other worlds...”

”So I’ll taste it... savor it... the finest flavor of all!!!”

Gluttony licked his palm, his crazed gaze locking onto Iris and the Crimson Demon lolis.

”Be careful.”

The princess drew her sword, shielding Megumin and Yunyun behind her.

The Authority of Gluttony was bizarre and dangerous—it allowed him to devour a person’s name and memories.

Losing one’s name would make them forgotten by the world. Losing one’s memories would reduce them to a hollow shell.

And worse—he could convert the stolen memories and knowledge into his own power, even mimicking the abilities of his victims.

”Oh, memory manipulation? Mind control-type?”

Senti didn’t seem impressed. She stepped forward, looking down at him.

A Herrscher and an Archbishop of Sin stood face to face.

Gluttony didn’t recognize the Herrscher of Sentience, but instinct screamed that this opponent was dangerous.

Which only made her... more appetizing.

He preferred to consume the minds of heroes and those with rich, vivid lives—they tasted far better.

”Come then, go ahead and try.”

Senti tilted her head.

”My mind’s overloaded with memories anyway. Maybe you can help clean it up a little?”

”?”

It was the first time anyone had ever challenged him outright. Overjoyed, Gluttony leaned forward eagerly.

”Tell me... your name, heehee...”

To use his Authority, he needed to know his victim’s true name.

”...”

Senti thought for a moment.

”My name is Fu Hua.”

”?”

Iris and the Crimson Demon lolis were dumbfounded.

Gluttony didn’t care. He licked his palm again, activating his Authority.

”Fu Hua... Fu Hua... what a strange name...”

”Well then, I’ll begin the feast...”

”Eat, chew, bite, gnaw, devour...”

He smacked his lips in the air, as though savoring invisible food.

A flood of alien memories—and power—poured into him.

The scale of it was staggering, thousands of times greater than any ordinary person’s lifetime of memories.

And within it flowed something completely foreign—Honkai energy.

”Guh—”

Gluttony’s mind was instantly overwhelmed by the torrent of chaotic memories. His consciousness spun, his head felt like it would burst, and the Honkai energy rampaged uncontrollably through his body.

”Oh damn, the Immortal’s memories fried his brain again!”

Onboard the flagship, Setsuna and the other shipgirls watching the broadcast couldn’t help applauding.

Technically, Fu Hua and the Herrscher of Sentience were one and the same—so Gluttony’s Authority had worked.

Unfortunately for him, devouring the Herrscher of Sentience’s mind also meant devouring endless centuries of tangled, self-replicating consciousness—and the full brunt of Honkai energy.

Sure enough, within moments, Gluttony was writhing on the floor, clutching his head in agony.

”Guh... what are you... why... so much...”

”Too delicious... too much... ugh, guh...”

”Tsk tsk tsk.”

”Five thousand years of memories, kid. Think you can handle that?”

Senti looked down at him with a mocking smirk, then raised her hand.

A chunk of Honkai energy condensed into a solid brick in her palm.

Smack—!

BOOM—!

”Lie down, you idiot!!!”

After dealing with the suddenly-appearing Gluttony, Senti rummaged through his memories and transmitted coordinates to the other squads, directing them to take care of the remaining two Archbishops of Sin.

Then, leading the Konosuba Squad, she continued upward.

They ascended the spiraling staircase all the way to the top of the tower.

The moment they stepped out, their field of view suddenly expanded.

Above them stretched an endless blue sky; beneath their feet was a vast circular platform, empty of walls or any additional structures.

From the platform’s edge, it was easy to look down upon the entire tower below.

They were now near the very summit of the Pleiades Watchtower, brushing against the clouds—a sea of mist and light swirling around them.

”Whoa...”

”So this is the top floor of the Pleiades Watchtower...”

The Crimson Demon lolis looked around excitedly, running about like children in a playground.

Boom—!

In the distance, the sound of wings thundered across the heavens.

The rumbling grew louder... and louder.

Then, with a deep, soul-shaking roar, a colossal dragon covered in azure scales broke through the clouds above.

It descended from the sky, landing before them with divine majesty.

Its sheer size was overwhelming—the tallest of them barely reached the height of a single joint on one of its claws.

Boom—!

The dragon exhaled, a gust of sacred breath rolling over the Konosuba Squad.

”Waaaah—!”

The shockwave nearly sent Komekko and Junjun—two of the smaller lolis—flying off their feet.

The dragon’s entire body shimmered with radiant scales, emanating holiness and authority—an image straight out of divine myth.

It was nothing like the greedy cave-dwelling dragons from fairy tales that hoarded treasure and awaited a hero’s challenge.

Hum—

The dragon lowered its gaze, its golden eyes locking onto the squad.

Its voice echoed directly into their souls:

[—Thou who hath reached the summit. Step forth, the one who hath ascended. Thou art the all-powerful petitioner.]

[—I am Volcanica. In accordance with the ancient covenant, I ask thee—what is thy desire?]

Its voice was booming and divine, resonating deep within their minds.

”Hiss—”

The group tilted their heads upward to look at Volcanica.

The Divine Dragon—the guardian deity of Lugnica, protector of the entire kingdom.

Only those who reached the tower’s summit, or the Dragon Priestess chosen through the Royal Selection, were permitted to meet it.

Any normal Lugnica citizen—or anyone in the Re:Zero world—would be trembling before such a being, bowing reverently and knocking their heads against the ground in worship.

Unfortunately, this was the Konosuba Squad—more specifically, a squad full of Crimson Demon lolis who had zero sense of reverence.

They began chattering among themselves noisily.

”It’s asking about our desire? What does that mean? Can we make a wish or something?”

”Isn’t that, like, a classic setup? You overcome a bunch of trials and then get to ask a god for one wish?”

”So what should we wish for?”

The most reasonable one, Yunyun, started thinking seriously.

”Treasure? We don’t really need that... Maybe more mana? Or some artifacts? Hmm... should we ask the Commander first...”

”Idiot.”

One of the other Crimson Demon lolis bonked her lightly on the head.

”If we figure out a way to bring it with us, we can make wishes every day!”

”—That makes sense!!!”

At that, Megumin stepped forward, clearing her throat as she stared up at the massive creature.

”I am Megumin! The Crimson Crest of Destruction, Monarch of Myriad Realms, the Archwizard who commands the strongest magic—Explosion!”

”Divine Dragon Volcanica! By the power of the ancient covenant, become my pet!!!”

”???!!”

Both Iris and Senti had several exclamation marks floating over their heads.

As expected of a Crimson Demon—to say something so utterly embarrassing with a straight face.

And to think she was trying to make the Divine Dragon her pet.

”...”

Volcanica didn’t react.

After a brief pause, it simply repeated its earlier words:

[—Thou who hath reached the summit. Step forth, the one who hath ascended. Thou art the all-powerful petitioner.]

[—I am Volcanica. In accordance with the ancient covenant, I ask thee—what is thy desire?]

”???”

”Is it deaf? Or does it just not understand what we’re saying?”

Megumin blinked, then repeated what she had just said.

”...”

[—Thou who hath reached the summit...]

Volcanica responded exactly the same way, its tone as flat and emotionless as a recording.

”Is this thing broken?”

Megumin raised her staff, chanting a spell to ”wake it up.”

”Darkness blacker than black and darker than dark, I beseech thee, combine with my deep crimson...!”

”Stop—!”

The Herrscher of Sentience stopped Megumin before she could set off a high-altitude nuclear-level explosion.

She looked Volcanica up and down carefully.

Then she extended her hand—a faint trace of Honkai energy seeped into the dragon’s body.

The Herrscher’s authority could easily read a person’s thoughts, memories, and emotions—and even modify them.

However, using her power on mythical beings like dragons was far more difficult. Their wills were unimaginably strong, far surpassing those of humans.

Even the dragon girls back at the base—Tohru, Elma, and Lucoa—were almost impossible for her to influence.

”Hmm? That’s strange...”

To her surprise, Senti found it remarkably easy to take control of Volcanica’s will.

And from within, she glimpsed a flood of fragmented memories—scenes of Lugnica’s founding, the covenant with the kingdom, and the fierce battle of the Three Heroes against the Witch of Envy...

Boom—

The great dragon slowly lowered its head, folding its wings and bowing before her.

”Wha...”

”All hail the great Herrscher of Sentience!!!”

The Crimson Demon lolis cheered in unison.

”I want to learn that trick, Great Herrscher of Sentience-sama!”

They thought being able to control a dragon instantly was the coolest thing ever.

”No.”

Senti shook her head.

”This thing’s just an empty shell. Volcanica’s soul isn’t here.”

”Huh?”

The others looked confused.

Information about the Divine Dragon Volcanica was scarce—it was mostly treated as background lore.

All anyone knew was that it was Lugnica’s guardian deity, that it had helped seal the Witch of Envy, and that those who won the Royal Selection could meet it.

As for everything else, there were no details.

”...”

Senti closed her eyes, sorting through the fragmented memories she had pulled from the dragon.

”Hmm... Four hundred years ago, when the Three Heroes sealed the Witch of Envy, to suppress Satella’s overwhelming power, the Divine Dragon sealed the soul of the Witch of Greed within the grave.”

”Volcanica and the other two heroes also left a huge portion of their own power there. That’s why this version of the dragon in the Pleiades Watchtower is just a hollow projection.”

”It only appears symbolically when a new king is chosen during the Royal Selection. Tch, no wonder it didn’t lift a claw when the Great Tomb’s undead army flattened Lugnica.”

When the kingdom had been overrun, countless people must have prayed to their guardian deity for salvation.

The Divine Dragon had once made a sacred pact to protect Lugnica’s peace, yet it never showed up in their darkest hour—for one simple reason: it couldn’t.

Over the centuries, Volcanica had spent most of its power suppressing the Witch of Envy and could no longer interfere with the outside world.

”Ah...”

The Crimson Demon lolis looked disappointed.

In their imaginations, this was supposed to be a glorious, earth-shaking battle against a divine dragon—an epic duel that ended with them taming it and reporting their triumph to the Commander.

Instead, it was over in seconds, effortlessly subdued by Senti.

”Then where’s its real body? And the Witch of Envy?”

”Should we go check it out?”

Megumin raised her hand eagerly.

”Hmm... I can find the sealing site in Volcanica’s memories...”

Senti tapped her chin.

”There’s even a record of how to undo the seal—it doesn’t seem that complicated...”

”Yay!!!”

The Crimson Demon lolis instantly swarmed around Senti.

”If we defeat the Witch of Envy, that’ll be an unprecedented achievement!!!”

”Wait—shouldn’t we ask the Commander first whether we’re supposed to recruit her or destroy her?”

”Komekko wants dragon meat...”

”...”

The Herrscher of Sentience rubbed her temples.

These little maniacs weren’t just reckless—they had terrifying amounts of energy and zero sense of self-preservation.

They only ever thought about one thing: chaos. And making it big.

Bzzt—

Suddenly, a holographic screen flickered to life before them.

The faces of Setsuna and Mio appeared on the projection, both looking a little helpless.

”Konosuba Squad, stand down. Return immediately. You’re about to trigger a boss.”

”We’ll handle what comes next.”

—

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