Crossover Shipgirls: Building a Dimensional Empire from Scratch

With the Siren threat neutralized, the full-scale development of the Azure Lane world officially commenced.

Swoosh—

Setsuna, accompanied by tens of thousands of Bulins, teleported to the port through the anchor point.

Without the Sirens’ interference, the entire world was serene and tranquil, with vast blue skies and seas. Not a single mass-produced ship could be seen. If not for the Bulins and small Manjuus still scattered around the port, this place could almost be described as an uninhabited planet.

Buzz—

The Eternal Snowfall, carrying several accompanying shipgirls, cruised high above in patrol mode, its sensors capturing every detail of the planet below. Occasionally, the ship would release Bulins from its lower hatches, scattering them across different seas to conduct exploratory missions.

”It’s really peaceful now...”

Gazing at the azure skies and endless seas through the observation windows, Richelieu, Taihou, and Yat Sen found the sight almost surreal.

They had expected prolonged battles against the Sirens, leveraging advanced starships to finally eradicate the monstrous threat.

Instead, the Commander had done something completely unexpected—he had subdued the Sirens.

Of course, the Sirens had yet to fully trust Setsuna. For now, they had merely agreed to a ceasefire. Judging from the attitudes of Purifier and Observer, their current interest lay more in Setsuna himself than in the shipgirls, treating him as a unique subject of study.

At least there was no need for war anymore.

”I recall when we signed the cooperation agreement, Enterprise said something like this,” Setsuna began with a smile. ”’May you bring peace and prosperity to both worlds’? I suppose I’ve managed that now, haven’t I?”

”Thank you. You are now the Commander of all the shipgirls in the port,” Enterprise replied earnestly, her admiration evident.

Originally, their agreement was limited to non-aggression, trade, and military alliances. But now, Setsuna had effectively become the leader of the entire port.

None of the shipgirls objected to this. He had taken them to the stars, resolved the Siren menace, and shown them the wonders of countless worlds.

He had fulfilled every expectation they had of a Commander—and then some.

”Speaking of which,” Setsuna teased Richelieu, ”do you remember what you said during the Alliance’s founding ceremony when I talked about merging with the port in the future?”

”You called me insatiable, like a snake trying to swallow an elephant. Tsk, you really weren’t holding back…”

Poking Richelieu’s cheek, he laughed.

”Um…” Richelieu’s cheeks flushed, and she awkwardly murmured, ”I’m your oath ship now... so why even bring this up anymore…”

Seeing her bashful demeanor, a stark contrast to her usual composed self, Setsuna couldn’t resist cupping her face and planting a gentle kiss on her forehead.

”You’re adorable,” he said with a grin.

Richelieu’s face turned even redder.

”Ughhh—”

”Can you two save the flirting for later? Aren’t we supposed to be surveying terrain right now?!” Formidable and Gudako exclaimed, shielding their eyes as if they had been blinded.

Clearing his throat, Setsuna returned the group’s focus to their mission.

With upgraded reconnaissance equipment, the starships no longer needed to rely on scout planes like the old aircraft carriers did. A single pass over the planet’s surface allowed the sensors to automatically map the terrain and provide detailed information.

Half a day later, the Eternal Snowfall returned to the port.

Setsuna handed the scan results over to the Bulins and briefly discussed them with the group.

This world, being an ocean planet, wasn’t suitable for large-scale land-based infrastructure. A portion of the Bulins and submarine shipgirls would need to be deployed to mine undersea resources.

As for the port… it could serve as a backyard retreat for the shipgirls, a place to relax and vacation when not busy.

...

Nighttime.

The main building of the port, in the upper-level office.

Richelieu exhaled deeply and stood up from her seat. After finalizing the development plan for the Azure Lane world, she had also taken care of some daily tasks, inadvertently working late into the night.

”Hm?”

When she stepped out of the office, she looked around and found the surroundings quiet and still. With Setsuna having brought only a small number of shipgirls on this trip, and the port now vast and sparsely populated, even the Bulins were few and far between in the building.

”What’s the Commander up to?… Could he also be staying up late?”

”I should go check on him,” she thought, adjusting her clothes and smoothing her hair. Almost unconsciously, she began walking toward Setsuna’s quarters.

Knock, knock, knock—

”Commander, are you there?” Richelieu softly knocked on the door, keeping her voice low. She recalled that Formidable and Gudako were also staying in nearby dorms. While she was proud of her status as an oath ship, showing up at this hour felt a bit inappropriate.

”No one’s here. Go away.”

A familiar voice came from inside the room.

”???”

Richelieu’s expression twisted in confusion. She opened the door to find Taihou lounging inside. Dressed in a short red yukata, Taihou lay lazily on the bed, exuding a seductive air, as though waiting for someone.

”What are you doing here?!”

Richelieu stared at Taihou in disbelief. Her attire seemed designed to fall apart with a single tug, and on the bedside table sat two glasses of poured red wine, accompanied by lit candles. The atmosphere was undeniably romantic.

Given the timing and location, there was no doubt in Richelieu’s mind that Taihou had ulterior motives.

”I should ask you the same—what are you doing here in the Commander’s room in the middle of the night?”

Taihou sat up, clearly displeased by Richelieu’s intrusion.

”How did you get a key?”

”I have a key to every one of the Commander’s rooms, whether it’s here, at the port, or even on the Eternal Snowfall~,” Taihou replied smugly, twirling the key in her hand.

”…”

”Get out and stop disturbing the Commander’s rest,” Richelieu attempted to persuade her.

”Do you take me for a fool? Why don’t you go back to your own quarters?!”

Taihou quickly caught on to Richelieu’s intentions, though admittedly, Richelieu was being a bit more subtle about them.

”You leave first.”

”No, you go.”

”At least put some proper clothes on first.”

The two of them bickered back and forth, exchanging one remark after another.

They almost summoned their rigging and started fighting.

Suddenly, a voice interrupted them from behind.

”You two, arguing in the middle of the night instead of sleeping?” Setsuna yawned as he walked into the room, his gaze shifting between Taihou and Richelieu. ”What are you even doing here?”

It didn’t take long for him to piece together the situation. He had gone out for a walk, only to return to find himself in the middle of an unfolding drama.

It was a choice, but as far as Setsuna was concerned, he wasn’t about to choose just one. He wanted both.

”Commander, I…” Richelieu began, but before she could explain, Setsuna gently pushed her into the room.

”You two are always bickering. Isn’t it time to resolve things and strengthen your bond?”

”W-wait, what?!”

...

The click of the door locking sent a wave of tension and anticipation through both Taihou and Richelieu. The hostility that had defined their interactions began to fade, replaced by a shared sense of unease and expectation as they turned their eyes toward Setsuna.

Despite their rivalry, both felt a sense of uncertainty. While they had often seen each other as competitors, this situation was something entirely different.

”Well? What are you standing there for? Sitting around stiffly like this can’t be comfortable,” Setsuna said, reclining slightly on the bed and motioning for the two to come closer.

”Commander, your imagination is truly something else…” Richelieu muttered, unable to resist a comment. ”If you had even suggested this a year ago—no, even half a year ago—I would have immediately fired my main cannons at you.”

”…”

”Well, you can always leave now if you want. Seems a bit crowded in here,” Taihou interjected, her tone laced with playful provocation as she turned to Richelieu.

”If anyone’s leaving, it’s you…” Richelieu replied, though her words lost their edge when another sensation made her let out a soft gasp.

Setsuna observed the two of them with amusement. They seemed compelled to compete over everything, always seeking to prove their own value within the fleet. Yet, as far as he was concerned, some things didn’t need a victor.

Each brought their own charm: Taihou’s twin-tails gave her an energetic allure, while Richelieu’s composed demeanor held a sense of conquest waiting to be won.

”Commander, you’re incorrigible…”

Both let out soft murmurs of protest, their hands instinctively pinching his arms in tandem.

”You two really need to get along and stop all this constant quarreling,” Setsuna chided with a chuckle.

At first, Taihou and Richelieu found themselves a bit overwhelmed by the unfamiliar situation.

However, with Setsuna’s gentle guidance, they soon began to adapt. Cooperation replaced rivalry as they found themselves working together.

What emerged was a seamless synergy, their efforts complementing each other perfectly to achieve an almost instinctive balance.

Taihou, as the first shipgirl, even took it upon herself to provide Richelieu with a live demonstration.

”You know,” Taihou said with a sly smile, her voice low and conspiratorial. ”The Commander really likes it when you do this…”

Taihou used her flight deck to demonstrate a few things that only carriers and battleships, as the elder sisters of the fleet, could manage. Richelieu, usually reserved and focused on her prayers and scripture, was utterly stunned.

”How can you even do that?! Where did you learn this?!” Richelieu exclaimed, her expression a mix of shock and disbelief.

”Commander taught Taihou, of course~~~,” Taihou replied with a blissful smile.

”Unbelievable…” Richelieu muttered, giving Setsuna another pinch.

”Well, did you figure it out?” Setsuna asked, amused.

”…I did,” Richelieu admitted, albeit with some hesitation.

”Then why don’t you try?” Taihou suggested with a knowing smile.

...

The next morning.

In the dining hall, Setsuna sat down for breakfast with Taihou and Richelieu. After last night, he found himself in need of some serious energy replenishment.

”Morning,” greeted Yukikaze and Formidable, noticing the trio as they entered.

”How odd. They’re not arguing today,” Yukikaze whispered to Formidable. ”They’re both just calmly following the Commander?”

Yukikaze blinked, finding the sight unusual. Normally, whenever Taihou and Richelieu appeared near Setsuna at the same time, some form of conflict or petty competition would inevitably arise. Their ongoing rivalry had become a well-known spectacle within the fleet.

Today, however, the two seemed completely different.

Even more shocking, Richelieu was actively serving Taihou, placing items on her plate.

”Last night must have been hard on you,” Richelieu said, offering Taihou a pack of yogurt and several pieces of chocolate.

”It’s fine. Honestly, I think it was a good experience, even if a little tiring. Maybe we can do it again together next time?” Taihou replied courteously.

”Hmm…” Richelieu considered. ”That would depend on the Commander’s decision…”

”???”

”The sun must be rising in the west!”

The sudden display of camaraderie left Victorious, Formidable, and Enterprise utterly stunned. They had to spit out their drinks in shock.

How could one night transform two of the fleet’s fiercest rivals into a pair that now behaved like sibling ships?

”Commander, do you have any idea what’s going on?” Formidable tugged on Setsuna’s sleeve, her curiosity getting the better of her.

”Oh, nothing major. We just worked on deepening their bond a little,” Setsuna replied with a nonchalant yawn.

”Deepening their bond?” Formidable tilted her head, puzzled. ”Can I join next time?”

Setsuna froze for a moment, staring at her.

”Two armored carriers and a battleship... Uh, I’ll do my best?” he replied, uncertain if he was ready to handle such a challenge.

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