This was a world of despair—one where the Gastrea had triumphed, and humanity stood on the brink of extinction.
Even though humanity had managed to destroy the Stage V Gastrea of the Zodiac—Taurus and Virgo—it had come at a staggering cost.
Overall, mankind still clung to survival, driven into dwindling territories as the Gastrea tide consumed all before it.
The survivors, trapped within their Monolith-walled cities, had long believed this state of decline would continue indefinitely—that humanity would ultimately be wiped out.
Until the day they came.
The black-armored giants who descended upon the world from the Tokyo region of the Japanese Archipelago.
The terrifying Gastrea, which had driven humanity to the edge of annihilation, were defeated with ease.
Even the mighty Stage V Gastrea—monsters that had once required entire armies and immense sacrifice to bring down—were annihilated in mere hours.
Yet the people of the Black Bullet world found no salvation in this.
For by the will of Empress Selene, Alex's First Astartes Legion carried the flames of war across every land.
...
Boom!
"Enem—" Bang!
A thunderous explosion shook the outer perimeter near the Monolith fortification. A sentry standing on a raised platform shouted in panic—only for his voice to cut off abruptly as his head exploded like a melon, helmet and all.
Blood and bone splattered across the sandbags, stunning the soldier beside him into petrified silence.
A moment later—bang!
The sandbag-and-concrete wall of the defensive position burst open, a gaping hole the size of a man torn through it. The soldier crouching behind it barely had time to react before he was blown apart.
The assault did not stop there. A grenade the size of a man's fist rolled through the breach, bouncing once before landing at the feet of several dazed soldiers.
BOOM—!
A searing flash consumed the narrow trench. When the light faded, only shredded remains clung to the walls, painting the corridor in a grotesque mural of red and black.
Moments later—crash!
Stone fragments scattered as the compromised wall gave way completely. Through the dust burst a towering figure clad in pitch-black power armor, wielding a bolter—the unmistakable form of an Astartes.
Thud, thud, thud—
More followed. Several Astartes, their black armor gleaming faintly in the smoke, advanced through the breach with lethal precision.
Behind them poured ranks of Imperial soldiers—mortals clad in black composite combat suits, their design a fusion of ancient and modern military aesthetics.
Their helmets bore faceguards, and beneath the armor were the gray-black uniforms of the Imperial Army. Over this, they wore light armor painted in the same black livery as the First Legion.
The design resembled modern tactical vests, adapted for combat against superhuman foes. Each carried an oversized rifle and a soft-metal backpack.
(Note: Compared to Astartes power armor, these were indeed 'light' by Imperial standards.)
Their weapons were far heavier than the standard rifles used by human defense forces of the Black Bullet world.
In fact, they were intentionally so. The Imperial Science Bureau had designed them based on the physical capabilities of Imperial citizens—whose strength far exceeded that of baseline humans.
Each rifle weighed over twenty kilograms—heavier than many nations' squad automatic weapons.
In any other world, issuing such weapons would have been madness. But in Selene's Empire, where an average soldier could crush stone bare-handed or wrestle beasts to death, this level of armament was entirely practical.
Though far less massive than the monstrous bolters of the Astartes, these rifles still packed devastating power.
"Legion Commander's orders—advance and finish the battle!"
A tall Astartes officer, his armor adorned with intricate golden patterns, ducked through the ruined breach. Through his internal comms, his cold, mechanical voice echoed with precision and authority.
At his command, the Imperial soldiers who had breached the defense lines raised their weapons as one.
"Remember—leave none alive who stand in our path! Time is of the essence. Her Majesty will soon descend, and we must purge all resistance before she arrives!"
The Astartes officer's voice thundered through the internal comms.
"Yes, sir!" came the unified roar in response.
Both Astartes and Imperial Auxilia raised their weapons high, voices blending into a single, thunderous chant:
"For Selene—! For the Empire!"
They had no concern for being overheard by the defenders of the Monolith-guarded human settlements nearby. After all, the attack was not isolated—across the entire region, detonations shook the land as coordinated assaults erupted from all sides.
Boom! Boom! Boom! Boom!
A chorus of explosions engulfed the city from every direction. Black-armored Astartes and their Imperial Auxilia advanced methodically through the ruins. The scent of blood hung thick in the air, clinging to every street and shattered building.
With each roar of the bolters, organized resistance was obliterated. Every minute, another defensive strongpoint fell silent beneath the Empire's relentless onslaught.
...
"That must be the last human settlement remaining, then."
Standing upon a hill overlooking the city, Alex surveyed the desolation before him, surrounded by his Honor Guard.
"Tch... I don't get it. These outer zones—what did they call them, 'Outer Areas'?—they never think to rebuild or expand outward? Hiding in these cramped holes forever can't be a long-term plan."
He rested one gauntleted hand on his helmet, shaking his head. "And you can see children here too, can't you? Young ones everywhere."
"Yes, Lord Commander," replied one of his Honor Guard. "In every major city we've conquered, we've consistently found large groups of young females abandoned in the ruins of the outer zones."
"Then it's the same procedure as always," Alex ordered. "Astartes are to clear out every Gastrea near the perimeter. The Auxilia will secure and retrieve the 'Cursed Children.'"
He turned his gaze toward an Auxilia officer wearing a peaked cap, giving a curt nod.
To conquer a world, rather than annihilate it, required more than the superhuman might of the Astartes. The inclusion of vast Imperial Auxilia made the process efficient and sustainable.
The earlier full-scale Astartes assaults had merely been tests—meant to gauge the strength of local resistance. Tokyo's bad luck had been crossing paths with the only instance of a pure Astartes-led siege on this world.
In subsequent campaigns, Alex had already learned the general range of their military capability. Some settlements were better defended than others—but none strong enough to make a difference.
The Astartes served as the spearhead, smashing the toughest targets, while the Imperial Auxilia followed to occupy and secure. The rest of the Astartes focused on purging Gastrea infestations.
To Alex, the Gastrea were far greater threats than the humans of this world.
As for diplomacy or appeasement? He had no patience for it. Only a few human cities still held out—and this one had proven especially troublesome, demanding special treatment and even partial autonomy.
Utterly absurd.
They didn't understand reality at all.
"Enough talk. Attack."
"By your command, Lord Commander!"
"Prepare quickly. The battle is almost finished—and Her Majesty will arrive soon."
Turning away, Alex gazed upon the distant city once more.
The massive black Monoliths lay shattered, smoke and fire rising from uneven gaps where they had fallen. The city's once-modern skyline now burned, broken and scarred by war.
...
Elsewhere—
"Gastrea virus..." Selene murmured, examining a fragment of blue-black chitin from a slain Gastrea. Her expression was one of mild fascination.
Having arrived in the Black Bullet world alongside Dr. Stylish, Selene had chosen not to seize the World Core immediately. Instead, she directed her entourage to investigate the Gastrea-infested zones.
What had once been a vibrant urban metropolis was now a wasteland—a vast playground for the Gastrea.
Overgrown forests blanketed the ruins. Though the Japanese archipelago was a temperate maritime climate, the environment before her resembled the humid jungles of the equator.
Except here, there was no chorus of life—no birds, no insects. Only silence, heavy and absolute.
Standing amid the overgrown ruins, Selene gazed at the crumbling remains of what had once been a street-side shop.
The once-white walls were now stained black and streaked with dark-green mold. The cracked floors and fractured ceilings looked ready to collapse at any moment.
Even after so many years, the stench lingered—thick, sour, and foul.
In one corner, a heap of decayed human bones lay scattered, half-buried beneath the rubble. It seemed that long ago—perhaps even during the early days of the Gastrea War—this had been one of the monsters' feeding grounds.
Dr. Stylish, whom Selene had sternly forbidden from injecting himself with the Gastrea virus, glanced at the remains with curiosity. "Your Majesty, the properties of this virus make it quite suitable for use as a biological extinction weapon."
"Yes, it has potential," Selene replied calmly. "But it's imperfect. It will require modification."
The Gastrea virus was a parasitic pathogen—an anomaly among viruses.
It infected humans and animals alike, rewriting their DNA to forcibly assimilate them into new organisms: the Gastrea.
"In a way," Selene mused, studying the samples, "it's an excellent prototype for a bio-weapon. But the existence of the 'Cursed Children'... gives it the troublesome trait of strengthening both friend and foe."
The thought of moral implications did not even cross her mind. As ruler of the Empire, Selene's instinct was purely analytical—how the virus could be weaponized, its advantages and flaws assessed, or perhaps replicated through Honkai Energy to produce an enhanced synthetic strain.
Something superior. Something controllable.
"Your Majesty!"
The familiar voice of Alex called out from behind her.
Selene turned, pulling her mind back from its wandering calculations. "Alex. So—it's finished, then? The final cleanup?"
Bowing deeply, Alex replied with solemn respect. "Yes, Your Majesty. I must apologize—it was only two hours ago that the last organized resistance was purged."
Selene gave a slow nod. "A little slow, but considering your approach—balancing subjugation with assimilation—you've preserved much of this world's remaining vitality. I'll overlook it."
She paused, thoughtful for a moment, before continuing.
"Originally, this world was to serve solely as your Legion's exclusive recruitment ground. However, the 'Cursed Children' you captured possess... potential."
"Therefore, this world shall also serve as a recruitment source for the 'Sisters of Battle.' Do you have any objections?"
"None, Your Majesty! I obey without reservation!" Alex responded at once.
He didn't mind in the slightest. If the recruitment involved only the 'Cursed Children,' that hardly interfered with his operations. Despite the heavy population losses caused by the Gastrea virus, the planet still had ample potential for recovery—and its technological foundation was strong.
As they walked, Selene's steps slowed slightly.
"Consider how best to manage this world as a Legion recruitment domain," she instructed. "Since your Legion is the first, I want you to draft a formal framework for future implementation. It will become policy—ensuring each Legion can expand its strength efficiently. The initial recruitment for the 'Sisters of Battle' will also fall under your supervision."
"Understood. However... the 'Sisters of Battle,'" Alex repeated softly, then hesitated. "Your Majesty, has General Esdeath returned?"
The word 'battle' alone conjured Esdeath's image—her infamous reputation as a sadist and battle maniac preceded her. If any existed who embodied the essence of war, it was her.
Given that, Alex had assumed Esdeath would command such a militant order.
"No, not Esdeath," Selene replied, her expression unreadable. "She has another task. The supreme commander of the 'Sisters of Battle' is Arisa."
"Lady Arisa?!" Alex exclaimed, utterly stunned.
"Your Majesty... are you certain? Lady Arisa... she's... I mean, no disrespect, but..."
He trailed off, glancing nervously left and right, searching for words.
Selene merely waved her hand. "Enough. Consider it a trial—her training."
"Yes, Your Majesty!" Alex straightened, the uncertainty fading from his voice. If it was Selene's decree, there was no more to say.
With renewed resolve, he bowed deeply. "Your will be done."