Crossover Shipgirls: Building a Dimensional Empire from Scratch

”Ah, Mama Tiamat’s maternal instincts are overflowing.”

Setsuna lightly touched Tiamat’s hand.

The next moment.

BOOM!!—

A violent tsunami erupted across the sea. Magical energy formed a massive vortex before him, wrapping Setsuna within it.

”Don’t... leave me again...”

”Come back, my child...”

She did not open her mouth, yet Setsuna heard that ethereal, gentle voice.

”Wait, has Mother mistaken the Commander for one of her creations—her child?”

Ishtar cried out in shock.

She could understand Tiamat wanting Uruk and human civilization to return to her.

But Setsuna, this outsider, clearly had nothing to do with Mesopotamia’s Creator Goddess.

”Ah, I get it.”

Kukulkan thought for a moment, then clapped her hands.

”She absorbed Master’s magical energy earlier. From Tiamat’s perspective, Master now shares the same origin as her—so that makes him her child.”

”It’s probably the instinct of a mother goddess. Master is the only child she can see right now, so she wants him to return to her.”

Tiamat sensed a familiar power from Setsuna, subconsciously treating him as her own child.

”Huh? Isn’t that backwards? She absorbed the Commander’s magic—how did she end up wanting to be his mom?”

Gudako stared, dumbfounded.

”That’s just how Tiamat is. All things in this world are her children.”

”Aaa...”

Tiamat held Setsuna in her palm and lowered her head.

Her enormous violet-red eyes, cross-shaped pupils glowing softly, gazed at him with tenderness.

This truck is way too big.

Setsuna had only one thought.

His power far surpassed Tiamat’s, yet standing in Mama Tiamat’s hand felt like he was the one holding a tiny chick.

Even driving a big truck had its limits.

Shhh—

Suddenly, from Tiamat’s hand and the surrounding tides, a surge of black waves gathered, wrapping Setsuna within.

”Uh, I may call you Mama Tiamat, but I don’t plan on returning to you.”

Setsuna waved a hand, an energy shield isolating the erosion.

”Why... my... child...”

Tiamat carefully lifted Setsuna to her chest.

Before that overwhelmingly enormous justice, Setsuna nearly suffocated.

Looking down, he saw an unfathomable white ravine—truly a wonder of the world.

”I gave birth to countless lives and was once loved by all beings. But my children treated me as a stepping stone and left me.”

”I only wanted to love them forever, to keep them by my side. Is my love... truly wrong?”

Tiamat held Setsuna against her chest like a compassionate mother.

Yet the pulling force surrounding him was a constant reminder—Mama Tiamat wanted him to return to her.

”Ah... I think I understand Mama Tiamat a little better now.”

Gudako smacked her lips.

She had been used as the soil that nurtured life. But once Earth’s environment stabilized and its ecosystem was established, Tiamat became unnecessary—exiled into the Imaginary Space.

When she returned to Earth, she had been filled with boundless hatred and sorrow, intending to sweep away humanity and return the world to herself.

But after venting her emotions in the Theater of Domination, she regained her rationality and once more became the ”Mother of All Things.”

”Humanity must leave the cradle and head toward distant horizons. I am not part of you, and you are not part of me.”

Setsuna spoke softly.

With a casual flick, he dispersed the magical energy wrapping around him.

Seeing that she could not make him ”return,” Tiamat seemed ready to simply stuff Setsuna directly into her body.

”Aaa...”

Tiamat froze. Her movements abruptly stopped.

Then came an unbearably sorrowful voice:

”So... you too will leave me, my child...?!”

”Don’t go. Don’t abandon me...”

BOOM!!—

A violent magical tide erupted across several kilometers of sea.

Tiamat’s body began transforming once more within the storm.

Wings sprouted from her back. Azure-gold scales covered her body. Her size expanded further, transforming into a colossal beast crawling upon the sea.

Low roars echoed from her throat as black tides surged from beneath her feet once again. Yin winds howled. The heavens changed color.

”Dragonification!!!”

”Tiamat’s taken dragon form! Commander!! She looks out of control again?!”

Everyone aboard the starship was startled.

Tiamat possessed the authority to evolve and remodel life. Dragonification was her ultimate combat form.

With sheer power alone, she could destroy the world.

Hummm—

A black-and-white barrier manifested before her, expanding outward in an instant.

”Anti-Genesis?!—”

The starship hurriedly evaded.

”Don’t get so worked up.”

Setsuna placed a hand on one of Tiamat’s horns.

”I’ll always stay with you, Tiamat.”

”In another world, I need you.”

Boom—

Spatial authority compressed suddenly, restraining all the overflowing black mud into a single mass.

Dragonified Tiamat offered no resistance, merely raising her head blankly to look at Setsuna.

After countless centuries, for the first time, she heard from her child—or the one she believed to be her child—the words, ”I need you.”

She stood there in a daze for a long moment.

Her massive pupils fixed on Setsuna as all attacks ceased.

”Uh... you’re a bit too big like this. It’s hard to talk.”

Setsuna thought for a moment.

”How about you try something? I prefer your human form.”

”...”

The giant beast before him seemed to nod.

Her body shrank rapidly.

Splash!—

Before long, she transformed into an ordinary human-sized figure standing upon the sea.

Her frame was petite, her features adorable.

Her violet-red eyes retained their cross-shaped pupils.

Long teal hair flowed down her back, and two large goat-like horns still adorned her head.

Tiamat had changed from ”Mother of Creation” to ”Daughter of Creation.”

Looking up at Setsuna descending slowly from the sky, she opened her arms, rose on her toes, and hugged him tightly.

”My child...”

”I am... Mother. I will protect you, help you. Please do not leave me again...”

”Huh?!”

Setsuna was caught off guard.

Mama Tiamat truly regarded him as her child. When a child tells an abandoned mother, ”I’ll stay with you. I need you,” the emotional impact was unimaginable.

”Even if... human language fades... even if... I cannot return to my original form... I will continue to guard you... I want to... keep guarding you...”

Tiamat spoke haltingly.

”...”

Setsuna pondered briefly. Forget it. No need to correct her. As long as Mama Tiamat’s settled, that’s enough.

After all, she saw everyone as her children.

He gently patted her head.

”Mm.”

”We’re heading to another world soon. This isn’t your home. Come with me.”

”...Alright.”

Tiamat’s voice was ethereal as she nodded.

”...Please... take me with you.”

”...Rely on me. I will be... very happy.”

Click—

A small shuttle landed atop the ship.

Holding onto the hem of Setsuna’s clothes, Tiamat followed him into the bridge of the Eternal Snowfall.

”Ahem. Well, even though everyone knows each other, let’s still do introductions.”

”Chaldea has a new member from now on—Beast II, Tiamat.”

Setsuna cleared his throat.

Tiamat’s gaze swept across the crowd.

”So many... people.”

”I am Mother—no, that is a title. My name is Tiamat. I arrive as an Alterego.”

”I will lend you my strength. I am very strong, because I am the Primordial Sea and the Second Beast... I will take care of Master... and all of you.”

Her voice sounded like that of a little girl. There was none of the oppressive aura of a world-destroying god—she even seemed a bit innocent.

”Aaaaaahhh!!!—”

Ishtar shrieked in agitation.

She shrank into a corner, hugging herself and trembling, not daring to look directly at Mama Tiamat.

This Singularity had already been absurd enough—she could accept joining forces with Quetzalcoatl as righteous allies.

After meeting Ereshkigal and Gorgon, things had become ridiculous. And now, even Beast II stood before her.

”What is wrong? ...Are you unhappy?”

Mama Tiamat asked gently with concern.

”I’m very happy! So happy I’m about to be scared to death!!!”

Even knowing Tiamat bore no hostility, Heroic Spirits instinctively feared her.

Snap—

Setsuna snapped his fingers.

The Theater of Domination shattered before them.

Outside the viewport, the scenery reverted to Uruk’s original appearance.

Beep—

An urgent communication from Chaldea connected.

”Mr. Setsuna, what just happened? You and Tiamat disappeared from the Singularity together?!”

”Chaldea can’t detect any energy fluctuations. What’s going on?!”

Roman asked anxiously.

Under temporal distortion, Mama Tiamat had remained inside the Theater of Domination for nearly half a month, while only a few hours had passed outside.

”Oh, it’s fine. Check whether the Singularity’s resolved.”

Setsuna asked.

”Huh?”

Roman froze, glancing at the scanner readings.

”It’s true—the remaining Lahmu in the Persian Gulf have vanished. The Singularity has returned to normal.”

”This is...?”

”Good. I’m taking Mama Tiamat home. We’ll meet again at the Grand Time Temple.”

...

”Mr. Setsuna, please wait! I have something I need to discuss with you!!”

”Please come to Chaldea first—I’m begging you!!!”

A short while later.

At Roman’s insistence, Setsuna led the team back to Chaldea.

A grand procession of Heroic Spirits followed behind him, an impressive sight.

”This is... Chaldea?”

”Master’s—no, the children’s place...?”

Tiamat looked around. The surroundings were completely unfamiliar.

Strangers operated unfamiliar machines.

”Ahem. First of all, congratulations. The Seventh Singularity has been successfully cleared. Mr. Setsuna, thank you very much.”

”Um... although I don’t quite understand how you defeated Goddess Tiamat, judging from the result, it seems... good?”

Roman cleared his throat, unable to stop glancing at Tiamat.

She had changed into simple white casual clothing, her hair tied back neatly.

If not for her pure, adorable face and the two conspicuous goat horns on her head, no one would associate her with Beast II—Evil of Humanity.

”Not defeated. I came of my own will.”

”Mother... protects... child.”

Holding onto Setsuna’s sleeve, Tiamat spoke slowly, haltingly.

She was still unaccustomed to human speech. Normally, she communicated with her creations without needing words.

As she spoke, her violet-red gaze settled on Roman.

”You... are not... ordinary human...”

”Mama Tiamat’s so smart.”

Setsuna patted her head. She narrowed her eyes and gave a satisfied hum.

”???”

Roman nearly cracked on the spot.

He leaned closer to Setsuna and whispered:

”Mr. Setsuna, is she really okay? Tiamat is the Beast of Regression—a catastrophic disaster rejected by Human Order.”

”Um... the Goddess of Venus, the Feathered Serpent, the Goddess of the Underworld are manageable. Gorgon has her sister watching her, so that’s fine too. But a Beast is completely different from them.”

”Even unconscious actions and instincts could bring planetary-level devastation.”

As a member of Chaldea, he understood how terrifying a Beast was.

Every time Setsuna visited a Singularity, he brought a few Heroic Spirits home. Roman knew about it, but Chaldea’s purpose was to restore Human Order—minor details like that didn’t matter.

This time, though, he had brought back several goddesses and a Beast.

It truly frightened him.

”Relax. Mama Tiamat’s super cute. I’ll take care of her.”

Setsuna pinched her cheek again.

”Mm...”

”I am... Mother. Don’t do that...”

”But... if Master wants to act spoiled... that is also fine...”

Mama Tiamat puffed her cheeks as she spoke.

”...As long as you’re happy.”

Roman gave up.

Only someone like Setsuna could keep a Beast in check.

After brief greetings and an exchange about the Seventh Singularity, he led everyone into Chaldea’s main hall.

The spacious room was filled with staff operating equipment.

Holographic interfaces floated everywhere. At the center, a massive screen projected a complex map of Earth, marking the locations of the previous Singularities.

”Now, let’s talk about the main matter.”

He tapped his device, projecting another map.

”Thanks to you, the detonation points placed by the King of Mages, Goetia, throughout human history have all been repaired.”

”From Orleans in 1431 A.D. to Babylonia in 2655 B.C., a total of seven major Singularities have been completely cleared.”

”Human Order has now been fundamentally restored.”

Gudako nodded in satisfaction, gazing at the marked locations on the map with a deep sense of accomplishment.

”Our work isn’t finished. Beyond the seven Singularities, there is one final location—Goetia’s headquarters: the Grand Time Temple.”

”It exists outside the timeline. It is also the Final Singularity.”

Roman brought up a complex interface on the holographic display, marking a coordinate that did not belong to Earth.

”Only by defeating Goetia there can Human Order truly be restored.”

”Ha!”

Gudako crossed her arms and leaned closer to examine the projection.

”So it’s the final showdown, huh?”

”Don’t worry, Doctor. Against Goetia, we have at least nine guaranteed ways to kill him. There’s absolutely no need for you to go activating some weird Noble Phantasm.”

”???”

Roman felt vaguely attacked.

Gudako had completely integrated herself into the Starsea Empire. Chaldea had become ”you,” while the Starsea Empire was ”we.”

After spending so much time with Setsuna, who knew what strange knowledge she’d picked up.

”So when do we move?”

Kukulkan clenched her fists eagerly.

”The Grand Time Temple doesn’t require standard positioning. It exists independently of the original timeline. We can transfer the entirety of Chaldea there via Rayshift.”

Roman answered seriously.

”So we only need a little time to prepare. It won’t take long.”

”Mr. Setsuna, we will soon begin operations against the Grand Time Temple. This will be the final battle to restore Human Order. The difficulty will far exceed any previous Singularity. Please be fully prepared.”

After clearing the seven Singularities, he entrusted the final restoration of Human Order to Setsuna and Gudako.

”—No problem.”

...

Hummm—

After saying farewell to Roman,

The expeditionary force returned to the capital.

Click—

The ship’s hatch opened.

Natives from more than two thousand years before the Common Era stepped directly into a flourishing super-metropolis of the interstellar age.

”Ah—”

Ishtar squinted against the dazzling sunlight.

”Welcome to the Starsea Empire.”

”Please proceed in an orderly manner to the residential district to register your identities. Angeloids will guide you on a tour of the capital.”

”We’ll rest here for now. Once Chaldea completes its preparations, we’ll head to the Final Singularity together for the decisive battle.”

Setsuna jumped down from the hatch, holding Tiamat’s hand as she followed.

Before long, they would likely head to the Grand Time Temple. He very much intended to bring Mama Tiamat along to beat up Goetia.

”Oh, right. Tiamat, you can’t casually use your authority here. If you want to remodel a planet for fun, I’ll take you somewhere else in the future.”

He reminded her casually, just in case she caused trouble in the capital.

”Mm...”

Mama Tiamat nodded while looking around curiously.

”Child... is amazing.”

”Humans... and other lives... so many... I love them...”

”...Do not... abandon me again.”

After countless centuries in Imaginary Space, she had long forgotten what civilization originally looked like.

The Starsea Empire’s capital had nothing to do with her as Mesopotamia’s Creator Goddess. Yet through her connection to Setsuna, she naturally extended her maternal instincts to the entire world.

If Setsuna was her child, then the world he possessed was also her child.

”...Alright.”

”Don’t worry. You can live here as long as you like. We’ll always stay with you.”

Setsuna knew there was no correcting Mama Tiamat. She could think whatever she wanted.

”Mm...”

Tiamat placed a hand over her chest.

”Thank you... I feel warm...”

As newly arrived companions of the Starsea Empire, Setsuna brought them to Chaldea’s residential district.

He instructed the Angeloids to arrange accommodations one by one.

”Whoa...”

Ishtar and Mama Tiamat looked around in fascination, sliding their fingers across holographic interfaces and inspecting various furnishings.

They had never seen so many electronic devices before. Even as goddesses and a Beast, the Starsea Empire’s technology felt like the distant future.

”Mm... not as large as my temple. But more fun?”

Ishtar looked around.

The great Sumerian temple had been vast but empty. Despite its size, it couldn’t compare to this compact duplex villa.

”Well? Are you satisfied with the conditions here?”

Setsuna asked.

Ishtar, Kukulkan, and the others had no objections at all.

”Master, where do you live?”

Mama Tiamat didn’t care about such details. Her gaze remained fixed on Setsuna as she asked softly.

”There.”

Setsuna pointed out the window to a towering structure piercing the clouds.

”That’s the Administrative Center. I’m there most of the time.”

”Occasionally, I stay at the port district or aboard the Eternal Snowfall.”

”Mm...”

Mama Tiamat lowered her head in thought. After a pause, she tugged at Setsuna’s sleeve.

”Then I... will not live here.”

”Child... should sleep with Mother. Master... same. Do not... leave me.”

”Huh?!”

Setsuna froze.

”When you say sleep together... you mean that in a wholesome way, right?”

—

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