Imperium of Man Terra Aeterna Season 01: Rise of Humanity's War Machin

Tokyo Bay, Offshore – Year 1912

When two armored aircraft carriers, a battleship, and two colossal cruisers appeared on the horizon—rising from the sea like moving iron fortresses—the whole of Japan was thrown into a state of shock.

Their size was staggering—dozens, even hundreds of times larger than the ironclads and armored ships anchored in military ports.

At the top of the main masts, a bold black flag flew with a double-headed eagle emblem. Beneath it, a shining white version of the same symbol—derived from the Holy Roman Empire, the inspiration behind the Imperium of Man—was clearly displayed, catching the eyes of all who looked.

In that era, Earth hadn't even conceived of aircraft carriers, let alone aerocarrier-grade technology. This sight wasn't just shocking… it felt like a nightmare born of some alien civilization.

Reuel had deliberately refrained from bringing spacefaring ships. His orbital fleet was currently being used by Ursarkar E. Creed to consolidate Imperium control in other regions.

For now, he relied solely on his naval fleet—the shipgirls.

Along the docks, a massive crowd gathered. People poured in from all directions to witness the arrival of the foreign armada.

The coast guard struggled to maintain order, though they themselves couldn't hide the shock on their faces.

Everyone stood frozen, staring at the approaching foreign vessels.

Beautiful, majestic… yet at the same time, oppressive.

A stark contrast to the stiff, somber Japanese ships—roughly armored and wooden hulls still clinging to the remnants of the feudal era—the smooth blue hulls of these foreign ships were stunning.

Though they retained a classic battleship design reminiscent of World War II, every inch of their surface bore clear signs of modernization.

The Richelieu, with its clean white hull adorned with golden patterns, twin command towers, and immaculate decks, looked like a moving piece of art.

The two armored aircraft carriers, Taisho and Hornet, followed behind with a far more intimidating presence.

Rows of parked fighter aircraft lined their decks—clearly not of this era's make.

"Well… their navy is so retro."

Belfast tilted her head, eyeing the rows of Japanese torpedo boats and armored ships lined up at the harbor. Her voice was soft, her tone laced with sarcasm.

"Reminds me of a pirate from the Royal Navy… never took things seriously. Even her fellow crewmates barely acknowledged her as part of the fleet."

Reuel chuckled, eyes gleaming.

"You're talking about that sailing warship…?"

Sailing warships from the Magic Line were strong enough to compete with steamships. But still, this world's navy simply had no means to keep up with modern technology—let alone the Imperium's.

Buzz—a whistle blew faintly in the distance, signaling the docking process.

Reuel stood on the deck of the Richelieu, eyes fixed on the now-dense crowd gathered at the docks.

Most of the people appeared short, thin, and malnourished—a reflection of the island nation's underdeveloped economy during the Taisho era.

The women of that time were far from the beauty standards of modern Japan in 2025.

Even the Coast Guard Commander—often mocked for his overly flamboyant appearance—could only stand rigidly still.

He welcomed Reuel in silence. His gaze was blank, his body tense.

Fear. Confusion. Anxiety. Shock.

All those emotions were written plainly on the faces of the onlookers.

Some of the older people among them began digging up buried memories.

Around fifty years ago, Commodore Matthew Perry of the United States Navy had led four warships into Edo Bay.

With cannon fire backing his threats, he forced the Tokugawa Shogunate to open Japan's ports to foreign trade—promising to destroy the city if refused.

Those black ironclads—later known as the "black ships"—became a symbol of the first clash between Japan and the outside world.

The technological gap back then had been so immense, it created a generational trauma that lingered deeply.

Eventually, Japan signed its first unequal treaty with the United States. The era of national isolation (sakoku) came to an end, and the downfall of the Shogunate began.

That incident would later be remembered as the Black Ships Crisis.

And now—

This moment felt exactly like that.

However—

The naval fleet of shipgirls that Reuel now commanded sent the entire nation into a frenzy. In the Taisho era, the concept of aircraft carriers was already a scientific fantasy—and now, they were seeing it with their own eyes.

There was nothing they could do except pray silently… hoping this foreign force didn't bring too much malice.

"....."

"....."

"Commander, I feel like we've become a world superpower."

The comment came half in awe, half in disbelief.

"We are,"

Reuel nodded calmly.

"Why did I never realize that being a global superpower could feel… so damn satisfying?"

So this is what it feels like to be the United States, he thought for a moment.

For Reuel, this was his first experience as Emperor of Mankind dominating another world. Though in Warhammer 40K's history he would eventually rule millions of planets, right now he was still taking his first steps—and this world was just one of many waiting to be conquered.

"From now on, we'll become an interstellar power… and force other worlds to sign unequal treaties."

Once the ships docked, the delegation was escorted by local guards.

Reuel, the shipgirls, and several representatives walked toward a palace that stood proudly in traditional Japanese architecture: surrounded by moats, high stone walls, and massive wooden gates—clearly designed to display the power and status of its inhabitants.

This was the Imperial Palace, Kōkyo, the highest seat of governance in this island nation. The residence of the shogun, a symbol of authority, and the embodiment of Japan's sovereignty.

After walking through long corridors, they finally arrived at the main hall. There, a middle-aged man clad in yellow imperial robes sat on an elevated platform, a symbolic crown resting on his head. Beside him stood an elderly man in a black kimono—clearly not someone ordinary.

The other officials bowed deeply, prostrated themselves several times, then withdrew in solemn silence.

"Is that the Shogun and the Emperor?"

Reuel glanced over disinterestedly, showing no intention of bowing or offering any formal greeting.

Taihou, beside him, muttered under her breath.

"What kind of grandeur are they trying to show off...? This is just a farce put on by primitives."

At that moment, one of the officials cautiously stepped forward to speak.

"May I ask, are you...?"

Their eyes fixed on Reuel and the shipgirls behind him. The black military uniforms bearing the golden double-headed eagle made their identity unmistakable: clearly not of this world. The massive armada in the harbor stood as undeniable proof of their overwhelming military strength.

"We are an expedition team from the Imperium of Man," Reuel said calmly.

"As previously stated—we come from another world, to discuss a cooperation treaty."

With a snap of his fingers, Richelieu stepped forward and handed over a document.

Bang!

Reuel slammed the document onto the table, directly in front of the Shogun and Emperor.

"On behalf of the Imperium of Man, I demand that this country surrender and become a tributary state under our control starting today."

"All agricultural, industrial, commercial, and production activities will be placed under our authority. You are required to submit resources and population tax annually."

"Disband all military forces, save for civil security personnel."

"In return, we will establish a new local military force called the PDF—Planetary Defense Force."

"And here are several other additional provisions…"

The Emperor and Shogun stared at him, visibly shaken. Though Reuel appeared young, there was a powerful, cold aura about him—far too intense to ignore.

The Shogun flipped through the pages of the document. Inside, it detailed a yearly tribute list: iron ore, coal, timber, textiles, agricultural products, and more. The proportions ranged from one-fifth to half of total national output.

Agricultural quotas were relatively lenient, but metals and industrial resources were taxed heavily. It was clear—the Imperium had a deep understanding of this world's social and economic structure.

The treaty was designed to ensure survival… while crippling future growth.

"If you're seeking an alliance, a treaty like this is far too one-sided…"

The young Emperor Taishō tried to suppress the tremble in his voice.

"This is the final proposal,"

Reuel tapped the table hard, his tone icy.

"There will be no negotiation."

"You have three days to give your answer."

"After that, if we receive no positive confirmation…"

"…the fleet will attack."

Shua—

With that ultimatum delivered, Reuel turned on his heel and walked out, followed by the shipgirls.

The hall fell into immediate silence. The local officials remained frozen in place, while Japan's two highest leaders could only stare at the document left on the table—cold sweat dripping, tension hanging in the air like a storm cloud just before the war breaks.

---

The Shogunate and society at large were stunned.

The shock caused by the arrival of the Imperium of Man's fleet far surpassed the Black Ships incident from fifty years ago. In many ways, this encounter felt even more intimidating—and downright outrageous.

The leader of the Black Ships back then had merely been a military commander from the United States Navy. Everyone knew he came from across the Pacific. The treaty they proposed had been relatively mild: the opening of treaty ports, appointment of consuls, and the granting of most-favored-nation status.

But this fleet from another world... did not belong to any earthly nation. Their technology was alien, far beyond the realm of human comprehension. If Reuel hadn't possessed a head and two legs like a normal human, the Shogunate might have mistaken him for an extraterrestrial being.

Even more terrifying was the sheer brutality of the treaty they offered.

"To recognize the Imperium of Man as a sovereign civilization, and to relinquish all production, economic, and trade activities to the direct oversight of the Imperium..."

"To provide a yearly tribute in the form of resources and population tax."

"In exchange, the Imperium of Man will not overly interfere in the internal affairs of local nobility..."

Once the Shogun finished reading the contents of the treaty, tension gripped the council chamber. Cabinet ministers (Naikaku), members of the Teikoku Gikai (Imperial Diet), senior advisors (Genrō), and military officers exchanged glances—faces a chaotic blend of confusion and dread.

Cruel. Unbearably cruel.

This was not diplomacy. It was an ultimatum—a demand to kneel and become a lapdog of an alien empire. They hadn't even bothered to request ports or trade rights—no, they demanded the entire nation be reduced to a well of resources and manpower under their control.

And it was clear: there was room for trade—but the other side wasn't interested. They hadn't come to negotiate. They came to seize.

A bitter truth that made one want to weep.

To sign that treaty would be to forfeit national autonomy. The country would become nothing more than a resource depot and conscription zone for the Imperium of Man, with no hope of independent growth.

"If we surrender without a fight and accept this treaty, the entire nation will curse us," said one military official.

"For the honor of our soldiers, we must hold our ground and resist."

"Then who exactly will step onto the battlefield?" asked Emperor Taishō (Yoshihito) softly, his face pale as he pictured the colossal aircraft carrier—larger than an entire city.

There was a proposal to launch a preemptive strike at the harbor, to seize their carrier before the situation escalated. But the idea quickly devolved into a mess of finger-pointing.

"Deploy the Kaigun Tokubetsu Rikusentai! This is the Navy's responsibility!" barked a general from the Sanbō Honbu (General Staff Office) with indifference.

"Tokyo Bay is under the jurisdiction of the Kaigun Tokubetsu Rikusentai! We'll advance!" shouted a naval officer, fury flaring as he accused the Army of cowardice.

"Shidan! Army! Cowards!"

"Kaigun Tokubetsu Rikusentai! Navy!!"

"….."

"….."

Yelling. Accusations. The argument flared out of control.

Each side tried to shove the burden onto the other.

But the hard truth remained: the tonnage of even one of their carriers exceeded that of the entire national fleet combined. The weaponry and aircraft it carried were utterly beyond the realm of Earth's current technological imagination.

To send torpedo boats against such a carrier would be an act of suicide. Such tactics might be conceivable twenty years in the future—but in the Taishō era, such forward-thinking warfare was decades ahead of existing military doctrine.

The atmosphere in the council room grew increasingly heated—debate surged to a boil, yet no solution emerged.

"….."

"….."

At last, Emperor Taishō (Yoshihito) spoke again, softly—almost as if speaking to himself.

"If military strength is not an option… then perhaps we must try to win over the heart of that fleet commander."

He lowered his gaze, then added, in a more serious tone:

"Find a way to speak with him again. There may still be a chance… to renegotiate the terms of that treaty."

---

The Next Morning.

Reuel let out a long yawn as he stepped out of his bedroom aboard the Richelieu. The morning was still draped in a thin fog, but the clarity of the report he had received was undeniable.

The message had come directly from Ursarkar E. Creed: the Cadia Shock Troopers had successfully seized control over the entire Kimetsu no Yaiba universe—save for one final location: the very place where God Emperor Reuel himself currently stood.

Reuel nodded in satisfaction. He didn't care how Creed had done it—as long as the end result bent to the will of the Imperium of Man, that was enough.

Without ceremony, Reuel ordered one division of Cadia Shock Troopers to immediately encircle the capital, Tokyo. Creed responded promptly: the order would be carried out as soon as possible.

Once the communication line cut off, Reuel walked toward the ship's balcony and gazed into the distance.

Along the shoreline not far away, the echo of gongs and drums rang out loudly.

A fully uniformed military band was solemnly performing a march. At the harbor, a middle-aged man who looked like a government official stood politely with two groups of attendants by his side.

"Commander, a diplomat from the Shogunate is requesting an audience. He says there's something important he wishes to discuss."

The message was relayed through the communication line by Belfast, one of Reuel's loyal ship girls.

"Oh?"

Reuel gave a small smile, then permitted them to enter the ship's receiving room.

A few minutes later, the Shogunate delegation arrived. After offering a formal bow, the diplomat gave a signal.

Several of his attendants stepped forward, carrying heavy wooden boxes. The contents were obvious: gold bars, pure silver, and antique jewelry.

The Shogunate's savings over many years, now presented as a gesture of tribute.

Reuel glanced at it. He neither rejected nor accepted it. He simply gave a quiet nod.

"Additionally," said the diplomat cautiously, "as the General has come from such a distant place, we apologize for not yet having hosted you properly."

"If Your Excellency doesn't mind, tonight we would like to invite you to the city and host a banquet in your honor."

"Ichiban Street is quite popular, even among foreigners. And tonight, there's a festival underway. I wonder... would Your Excellency be interested?"

The diplomats were polite and humble, as was customary in this island nation. But the offer drew puzzled expressions from the ship girls.

"What's… a street?" Richelieu asked flatly.

Belfast and Hornet exchanged confused glances.

A few seconds of silence passed, then Taihou looked at the guests with a sneer.

"Kabukicho," she muttered under her breath.

She elbowed Reuel from the side, her tone teasing yet sarcastic.

"Commander, you're… not interested in a place like that, right? We already have a giant phoenix onboard, y'know~"

"I'm not interested."

Reuel answered curtly and firmly.

He was no Julius Caesar. He hadn't come with the spirit of erotic conquest, asking if there were beautiful women in every city he took. He wasn't the "I came, I saw, I conquered—and bedded every woman" type.

The diplomat tried once more, this time more plainly.

"Of course… there are many beautiful and skilled women in the city right now. We are celebrating a festival, after all."

But Reuel only stared back with a cold gaze.

"I don't care about diplomatic ceremonies, high-ranking officials, local customs, or regional specialties. The only thing I want is an answer—do you accept or refuse?"

"Don't overthink it. Don't do unnecessary things. None of that matters."

"Go back, and let the Shogunate consider it seriously."

Silence.

The diplomat froze, his lips half-parted. Every speech he had memorized the night before vanished from his mind. The man before him was cold, unyielding, and left no room for negotiation.

At last, with a hoarse voice, he asked:

"But… why choose us?"

"Our country isn't rich in resources. Even as a tribute state, the amount we could offer each year is extremely limited. If you're looking for markets, there are many other nations that would be more suitable…"

Reuel glanced at him, then replied in an even tone:

"Because you're the closest. So you're the first."

In his heart, Reuel added silently:

"And every other country you just mentioned… already belongs to me."

He stood and gave a subtle gesture. Belfast and Richelieu immediately began escorting the guests out of the room.

Not a single country on Earth would be spared.

Be it the empire that once boasted the sun never set on its territory, or the tribal peoples living deep in the African savanna—all would kneel before the Imperium of Man.

"Mine when it's time to mine. Farm when it's time to farm. Fish when it's time to fish…"

"You will all have a bright future."