Crossover Shipgirls: Building a Dimensional Empire from Scratch

A few days later.

The expeditionary force began wrapping up operations in preparation for the return journey.

Eagle Union Federation, United Nations Headquarters.

A fleet large enough to blot out the sky descended upon the city.

Just like past conquests of other pre-space era civilizations, Setsuna dispatched a fleet accompanied by Angeloids. Without encountering much resistance, they took control of most of Earth.

Because humanity here understood the technological disparity between themselves and a spacefaring civilization—and the terms Setsuna offered weren’t exactly unreasonable.

Earth would be unified going forward, existing national leadership would be replaced, all countries would become vassal states of the Starsea Empire, and periodic tributes of certain resources would be required.

There would be no human experimentation, massacres, or blood sacrifices.

—After all, he looked just like a regular human.

As a result, aside from certain privileged elites, the vast majority of civilians had no objections. Their daily lives weren’t affected anyway.

As for a few hardheaded nations or small factions, they were quickly flattened by the Angeloid combat units.

The Americans were utterly stunned.

What the hell? I thought the aliens just came for a cube?

Turns out they came to conquer the world?!

Other countries that had previously dismissed the Americans as paranoid were also shocked.

So the aliens are real?! You guys secretly studied extraterrestrials in Area 22 for so long and pissed them off, and now the whole world had to acknowledge a new suzerain.

...

Meanwhile, Colorado, Eagle Union, Sector Seven.

Bzzzz

The Eternal Snowfall slowly descended onto an open field.

After the earlier chaos, the area had been reduced to near-ruins, with only a few broken research devices remaining.

As the hatch opened,

Autobots and Decepticons jumped out one after another.

The Siren shipgirls and Bulins reassembled several Decepticons who had previously been blown apart.

Upon first seeing the humans and Autobots, some of them panicked and prepared to fight to the death.

But were immediately stopped by Megatron.

The Decepticon leader had immense authority. After he explained the situation, the others accepted reality without much fuss.

Decepticons respected strength above all. Setsuna was, without question, the strongest among them—his combat capability far surpassed both Cybertronian leaders.

As for species?

Just look at the structure of Nu Gundam—he clearly was a Gundam! Not some weak human!

”You all stay here for now.”

Setsuna addressed the Transformers.

”Earth is under our jurisdiction. You may move about freely.”

”Once we finish building a lightspeed-capable ship, I’ll send you back to Cybertron and help rebuild your homeworld.”

Normally, the Autobots avoided exposing themselves in human society. But now that Earth was under his rule, they could walk the streets openly without issue.

”Wow We can enjoy peaceful lives now?”

”Honestly, Earth is more fun than Cybertron.”

Bumblebee let out a whistle, clearly enjoying life here.

With no Terrorcons or Decepticon threats, vacationing here wasn’t bad at all.

Optimus Prime, however, had a complicated expression. The Autobots advocated peace and coexisting with humans.

As for Setsuna’s actions...

Well, these were human internal affairs. Nothing to do with him.

He convinced himself of that.

The Decepticons, on the other hand, didn’t care at all.

To them, Setsuna was practically born to be a Decepticon leader.

Megatron had spent years plotting humanity’s conquest, only to find Setsuna doing it faster and more efficiently. His starships and Angeloids had easily crushed resistance across nations.

Too advanced. Too Decepticon.

The Decepticons were very much looking forward to the day Setsuna would recruit them for battle.

...

After taking care of the remaining matters, Setsuna set off on the journey home.

He had spent quite a bit of time in the Transformers world and was starting to feel homesick.

Whoosh—

Two days later.

The Eternal Snowfall slowly descended outside the capital.

Looking down at the little girls running and jumping in the streets, and the Angeloids soaring gracefully through the sky, Setsuna felt like he had returned to a paradise.

During the expedition, it wouldn’t be an exaggeration to say that he had spent more time dealing with those chunks of metal than with actual humans.

He was either running around with the Autobots or in constant conflict with Terrorcons and Decepticons.

Sure, steel and mechas are a man’s romance, but as an organic being, cuddling with soft, fragrant girls was also part of life.

Click—

After everyone disembarked from the bridge,

the crowd that came to greet them once again clogged the starship port completely.

”Onii-chan!”

Kayo Senju had returned to Earth early from the Starbase just to welcome Setsuna.

Standing at the front of the group, she was the first to rush over.

The little loli clung to his clothes, rubbing against his chest.

”You really came all this way just to greet me...”

”Don’t worry, I got both the Transwarp Key and the AllSpark.”

Setsuna rubbed her head, assuming Kayo Senju was anxious about the two items he had mentioned and came because she couldn’t rest easy.

”No, I just came to see Onii-chan!”

The blonde loli looked up, cheeks puffed with determination.

”Onii-chan is more important than the Transwarp Key! I... I haven’t seen Onii-chan in so long!”

”I just want to stay by your side...”

”...”

Too dangerous.

That was the only thought in Setsuna’s mind.

He pinched the little loli’s cheek.

”How about I make time to play some games with you? Maybe go to the park?”

”No, that’s too childish. I want to be like the shipgirl onee-sans and marry Onii-chan!”

Kayo Senju tugged on his sleeve as she spoke.

”...”

”You’re still too young. Let’s talk about it when you grow up.”

Setsuna’s face darkened.

This little scientist loli had an IQ over 200 even before her gene enhancement—afterward, she was practically on another level at 197.

One small issue that came with such high intelligence: her mental development was way ahead of her age.

While other little girls were still playing with dolls, Kayo Senju was already leading an entire research team conducting experiments at the Starbase.

”Oh? Commander, did you not bring back any girls from the Transformers world this time?”

Jeanne Alter scanned the people stepping off the starship.

It was just Gudako and the shipgirls—no strangers.

”I seem to recall every time you return from another world, we end up with a few more people in the base. And they’re not always human...”

”I thought you’d bring back some aliens this time.”

”...”

Setsuna coughed lightly.

”No, nothing like that. We were there on official business this time.”

”Got the AllSpark and Transwarp Key, resolved the Cybertronian issues, and came back right away.”

”Oh?...”

Jeanne Alter squinted at him, tilting her head in thought for a moment.

”Could it be because the 1994 timeline’s Transformers female lead was an eyesore and that world had no cute girls at all?”

”And since Transformers are all metal, not only do they pale in comparison to shipgirls, but the Commander also can’t use them at all?”

Gudako added with a soft, ghostly voice.

Bonk—

Ritsuka Fujimaru took a direct hit to the head.

”You talk too much! —”

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