Crossover Shipgirls: Building a Dimensional Empire from Scratch

On Europa, Tiamat displayed to everyone the power of the Womb of All Beasts and the Primordial Beast.

After creating a basic ecological environment,

the Sea of Life gradually receded from the land and returned to Tiamat’s side.

The planet, which had originally been half-frozen, suddenly grew warm.

The ancient ice sheets that had covered the land for eternity were replaced by lush forests. Birds and beasts moved through the woods, and from time to time, clear cries or the low growls of predators echoed through the trees.

A gentle breeze passed. A flock of unknown birds took flight in alarm, flapping their wings as they scattered in all directions.

The ocean also regained its deep blue color. Looking down, one could see schools of fish and shrimp in the shallows, and small animals crawling along the beach.

”My heavens...”

Several little girls from the Life Sciences Division who specialized in paleontology stared in stunned silence.

They realized that most of these were creatures that had gone extinct on Earth many geological eras ago.

Some species they recognized and could reconstruct from preserved DNA. Others they had never seen before and had only existed in theoretical speculation—yet now, they had all evolved one by one from the Sea of Life.

Of course, though they looked like ancient organisms, in essence they were created by Tiamat through her own authority and impressions.

Tiamat was simply familiar with these creatures, so she casually molded a batch of them.

”The planet’s climate has also been transformed,” Kayo Senju said as she observed the holographic interface.

”Air temperature, humidity, atmospheric composition—they’re all changing. This planet is alive now.”

In the past, planetary terraforming had always been a massive undertaking.

It required creating an artificial atmosphere, reshaping planetary landforms through various means, and if necessary, even acquiring weather-control scrolls from the Magic Department.

Tiamat’s remodeling of the planet was unbelievably thorough. Not only had she turned a frozen world into a habitable one, she had, even more astonishingly, created an entire ecosystem out of nothing.

In a short span of time, the planet’s life and environment had undergone tens or even hundreds of millions of years of evolution.

If left alone, perhaps in the distant future, intelligent life might even emerge on this world she had created.

”Hiss... We could just go ahead and colonize this planet, couldn’t we?” Gudako looked around. Europa now possessed the scenic beauty of an untouched primordial world.

If it were turned into a vacation planet, coming here to see ancient organisms and experience the beauty of nature would indeed be wonderful.

”I’ll give it to you... If you don’t like it, I can change it again... mm.”

Tiamat tugged at Setsuna’s clothes and opened her arms, asking for a hug.

”I... am I very capable? You can rely on me more... that’s okay too...”

”Mm.”

Setsuna hugged Tiamat.

”You’re very capable.”

”Good child~”

Tiamat’s maternal instincts surged. She stroked his head and patted him as if soothing a child.

”???”

Setsuna couldn’t shake the feeling that their positions were somehow reversed. In the past, he had always been the one giving head pats to others.

”Wow...”

The group of research little girls had no time for gossip. They began counting on their fingers, calculating future planetary transformation plans.

”If frozen planets can be transformed, then ordinary barren planets, lava worlds, or even toxic planets should be possible too...”

”Aside from gas giants, most rocky planets could probably have entire ecosystems created directly by Tiamat... Ah, doesn’t that mean the number of habitable planets just multiplied several times over?!”

”Also, studying the planetary biosphere itself is a huge project. We need to analyze how the Sea of Life allows organisms to evolve and iterate so rapidly within it...”

The little girls surrounded Tiamat, peppering her with questions.

”How large is the transformation range? Could you handle something as big as Earth? What about a rocky planet the size of Jupiter? Can you create ecosystems with completely different climates?...”

”...Eh?”

Surrounded by children, Tiamat was briefly surprised, then revealed a gentle, maternal smile.

”Mm, I can.”

”Being needed by children... makes me very happy.”

”Hiss...”

”Um, wait just a moment!!”

Mobius suddenly raised her hand.

”Regarding the life created and evolved within the Sea of Life, I have a few small questions.”

She casually picked up a strange little insect from the ground and observed it in her palm for a moment.

”This is a new species I’ve never seen before... Aside from ecological fusion and individual proliferation, the authority of the Sea of Life also includes self-modification, correct?”

”In other words, every organism’s evolutionary process and evolutionary outcome can be controlled and determined by you. You can decide what they grow into and what they evolve into.”

”Mm?... Yes.”

Tiamat nodded.

To her, there was no distinction between different forms of life. Within the Sea of Life, species could freely evolve, fusing traits with one another, or be altered entirely according to her will.

”Then, may I ask—what is the endpoint of evolution?” Mobius asked.

”Are you able to create a perfect organism?”

”Eh?”

Tiamat looked slightly puzzled.

”They... are all children I created. There is no superiority or inferiority.”

”A perfect organism... what does that mean?”

”Mm...”

Mobius pondered for two minutes.

”I mean a being whose strength, agility, intelligence, and so on completely surpass humanity. A being that gathers the advantages of all organisms, can evolve without limit, and is capable of rivaling extraordinary existences?”

After years of researching biological evolution, she hoped to seek answers—and direction—from Tiamat.

”Mm...”

Tiamat paused, then shook her head.

”...That is not possible.”

”I can allow humans to evolve wings and other organs, to become stronger and faster new humans. But to reach the level of perfection you described, there is only one possibility.”

As she spoke, she opened her arms.

”Return to me.”

”Children are born from the Sea of Life. They are parts of me—fragmentary and incomplete. When they return to me and merge as one, that is the endpoint of evolution.”

”Ah???”

”Are you talking about the Human Instrumentality Project with me??!”

Mobius felt an inexplicable sense of familiarity.

The difference between human and creator-god ways of thinking was simply too vast. She could not understand Tiamat’s philosophy or ideas at all.

”Forget it. We’ll just continue researching genetic technology and super transformation surgery...”

Thinking of the Lahmu’s appearance, Mobius felt that letting Tiamat freely control evolution might turn humans into who-knew-what.

She didn’t mind what her own children looked like—no matter how strange—but the Life Sciences Division, Setsuna, and the other girls certainly cared.

”Mm, but we’d still like to study the Sea of Life more. Could we observe the evolutionary process of organisms inside it?”

One little girl poked Tiamat.

”Maybe we can extract useful genetic ascension factors.”

”You can.”

Tiamat wore a gentle smile.

”But you must be careful.”

Her control over her authority was guided purely by instinct. These children seeking to study it through another approach—she found it wondrous and interesting.

...

”Come visit again when you have time!!—”

A few hours later, as everyone left the Life Sciences Division, a group of little girls waved reluctantly to Tiamat below.

”Aa... Aaa...”

Tiamat sat beside Setsuna, waving back while humming a strange tune again.

”They are... all good children, mm.”

”Um... you seem pretty happy?”

Ishtar felt that ever since Tiamat had arrived in the Starsea Empire, her behavior had been somewhat unusual.

”Being needed and respected by children... makes me very happy,” Tiamat answered seriously.

She could sense everyone’s goodwill toward her. Being needed was the greatest wish of the once-abandoned Womb of All Beasts.

”I... love Master, and them.”

”From now on, Master, I will take care of you... eating, sleeping, going out... we must always be together!”

”?”

”Wait, is Tiamat starting with max affection because of the children filter or something?” Gudako was baffled.

”Commander, I have a question. What exactly does she want to be to you?...”

...

A few days later.

Whoosh—

The shuttle landed once more in the capital, and Setsuna returned to the administrative center.

”Ahem. The tour ends here. Settle down and live well here. If you need anything, just say so. Within my ability, I’ll do my best to satisfy you.”

He sat back in his seat.

Normally, matters like this would be handled by Angeloids. This time was a bit of an exception—he was giving Tiamat and the other goddesses some face.

”...It really was amazing...”

Ishtar and Quetzalcoatl were still reluctant to leave, clearly feeling that their horizons had been broadened.

”Mm... You said there’s a god here with the same status as me, right? I’d like to go find her and exchange some pointers.”

”If we can spar a little, even better.”

Quetzalcoatl was the first to make a request.

”Lucoa is at the Imperial Grand Library. Go find her there.”

”Oh, and if you two are going to fight, do it in outer space or the training grounds. Don’t cause trouble in the capital.”

Setsuna pointed in a direction.

A few minutes later.

Inside the grand library on one side of the capital.

A dragon girl with wavy golden hair rested her cheek on one hand, dozing at a desk.

”Zzz... Zzz...”

”Still a little left... of the magi-theory materials... Zzz...”

Suddenly—

Bang—

The door was flung open.

”Please remain quiet inside the library. If you need materials, use the self-service search tool or magic...”

Lucoa opened her half-lidded eyes and spoke lazily.

”Hm?!”

She suddenly noticed someone standing in front of her—wearing feathers in her hair, carrying an oar-like greatsword, dressed like an Aztec native.

”Wow, so you’re the Feathered Serpent Master mentioned? Lucoa, right? You’re different from what I imagined.”

”Eh? And you are?...”

The great dragon girl jolted upright.

”I’m Quetzalcoatl. Our names are essentially the same, mm, and so are our identities.”

Quetzalcoatl crossed her arms, carefully sizing Lucoa up. From her, she sensed an identical aura.

”Come on, how about a wrestling match? We’ll stake the name of the Feathered Serpent God on it?”

”Huh?”

Lucoa had guarded the Starsea Empire for many years and was one of its high-end combat forces, rarely going out to fight.

She had thought she could keep slacking off as a librarian forever. Who would’ve guessed she’d end up challenging herself.

What kind of nonsense was this.

Boom— Crash!!—

Before long, earth-shaking sounds erupted from the training grounds.

[Blazing flames shall burn even gods to ash!!]

[Piedra Del So!!]

Rumble!!!

”Whoa!!—”

Ordinary girls training nearby looked up at the battle of gods in awe.

...

”...There’s no god here identical to me. I don’t really feel like fighting anyway...”

After sending Quetzalcoatl off, Ishtar brushed her hair back.

”Oh, I know what you want.”

Setsuna produced another pouch of gemstones and tossed it to her.

”Go help out at the Magic Academy. They’re collecting and recording magecraft from various worlds.”

”Then I won’t hold back!—”

Ishtar hugged the gemstones, her face clearly saying, You really get me.

After arranging the others, Setsuna looked at Tiamat.

”And you?”

”Mm...”

Tiamat gently shook her head.

”I... don’t want anything. Because I am Mother. Being with my children is most important.”

”Master, if there is anything you need from me, I will help you.”

”Hiss—”

Setsuna surrendered. As expected of Tiamat.

”Oh, then suit yourself. The Life Sciences Division may need your help in the future. As for me... there’s nothing for you to do for now.”

He thought for a moment.

With Tiamat around, future planetary transformations would save a lot of trouble. If he brought her along next time he went to the Type-Moon world, who knew what interesting reactions might occur.

”All right. I want to... watch you more.”

Tiamat sat not far away, propping her chin in her hand as she watched Setsuna with gentle eyes.

She regarded the Starsea Empire as her children, yet she knew nothing about Setsuna or this unfamiliar civilization.

She wanted to understand him more—see how he and the others lived here.

”Being stared at while working is a bit stressful...”

Setsuna had long realized that Tiamat’s way of thinking was always peculiar.

Still, having her stay by his side wasn’t bad. At least she looked adorable.

”Ahem. All right, let’s deal with the remaining matters.”

The trip to the Seventh Singularity hadn’t taken long. Most routine work had already been handled by the Sophons or the shipgirls.

Only a small number of important matters required his personal attention.

For example, the ongoing Galactic Wonder construction projects. As time passed, more and more megastructures were nearing completion or entering operation.

”Report. The main structure of the Synaptic Lathe has reached 72.7% completion. It is expected to be finished within six months. However, there is a small problem.”

The holographic interface opened. Grey’s report arrived first.

She stood in a distant star system thousands of light-years away from the solar system, waving at Setsuna.

Behind her loomed a hemispherical megastructure the size of a star.

Countless lateral wings extended from its edges. On each wing were innumerable cultivation pods. Millions of Bulins and Angeloids moved back and forth, carrying out construction work.

”Commander, the main body of the Synaptic Lathe has been completed. After calibration, it can begin operation. However, our wetware quantity is insufficient.”

The Synaptic Lathe functioned by linking biological brains together into a super neural computational network. It required ”fuel”—or rather, ”wetware”—to operate.

”Hm?”

Setsuna paused.

”Weren’t you planning to grab some aliens from other universes? We have plenty of vassal universes. Just catch some at random. I’ll grant you operational authorization.”

”Mm... that is possible. But considering the scale of the Synaptic Lathe and the Research Division’s needs, we require higher-quality wetware.”

The nanomachine replied.

”Given the computational scale the Research Division intends to perform, ordinary carbon-based organisms would probably burn out in two or three years. Their efficiency would also be insufficient...”

”So we hope to obtain a superior species to insert into it.”

”Ha?”

Gudako silently raised her evaluation of Grey’s moral standards. Compared to this, Goetia lacked imagination.

One incinerated human history. The other literally burned humans as fuel.

”So ordinary organisms can’t meet your computational requirements...”

Setsuna tapped the desk.

”Go on. What kind of wetware do you want? I’ll think about it and see if I can bring some back from another universe.”

”Now that’s the spirit!”

Grey perked up, leaning closer to the holographic interface and counting on her fingers.

”First, the fuel—uh, wetware—must exist in sufficient numbers. They must possess intelligence. Unawakened species have too little processing power.”

”Secondly... it would be even better if they were smarter. Ideally emotionally indifferent and not easily disturbed by external stimuli. That way their computations remain stable.”

”If possible, they should also possess some magical traits—like resurrection abilities? That way we can recycle them efficiently and infinitely.”

”Not just ordinary humans or aliens. Magical species are fine too! We’re collaborating with the Magic Department to adapt the Synaptic Lathe. We can burn anything!”

She enthusiastically listed a pile of requirements.

”Oh? The standards have increased.”

Setsuna summarized the nanomachine’s demands.

”So you want a species with sufficient population, high intelligence, emotional detachment, rarely experiencing fear, capable of using magic, and possessing near-infinite resurrection ability—to serve as fuel for the Synaptic Lathe??”

”Do you think the Commander is a wish-granting machine?! Where would such a bizarre species even exist?!”

The large-eyed girl who had been slacking off at the side couldn’t help but complain.

When laid out like that, the species sounded as if it had evolved solely to be stuffed into the Lathe. It was hard to imagine aliens naturally developing in such a way.

”I’m not in a hurry. I just wanted to give the Commander advance notice.”

”If all else fails, we can grab a downgraded version?”

Grey scratched her head.

”...”

Setsuna thought for a moment.

He jotted down the bizarre requirement in his notebook.

”What a coincidence. I actually do know of such a species. We should be meeting them soon.”

”Heh. The more I think about it, the more they sound like heaven-sent wetware. It would be a waste not to shove them into the Synaptic Lathe.”

—

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