The Sisters' Battle.

Natasha opened her eyes. The world was no longer blurred by tears or clouded by doubt. The black rain still fell, but now it seemed to clarify her vision instead of darkening it.

She looked down at the horde of undead surrounding her, moaning and shuffling across the wet asphalt. Bodies of former comrades, now reduced to puppets of rotten flesh. She no longer felt pity. She no longer felt horror. She only felt a cold, absolute clarity. They were obstacles. They were an insult to the memory of the living.

Without a single doubt in her heart, Natasha bent her knees and lowered her center of gravity. Her right hand gripped the katana's hilt with a newfound firmness, while her left hand held the scabbard. The air around her began to vibrate. It wasn't her usual purple aura; it was something denser, heavier. The rainwater that touched her skin evaporated instantly with a hiss.

"Rest in peace," she whispered.

In a swift motion, she drew her blade. SHING!

It wasn't a simple cut. It was a release of energy accumulated over years of pain and training. A shockwave of pure Kijin Essence shot out in a perfect 360-degree circle around her. Time seemed to stop. The rain froze in the air. And then, destruction.

The fifty undead surrounding her were cut in half simultaneously. There was no resistance. Their bodies separated at the torso and fell to the ground in synchronized silence as the purple energy incinerated the dark magic animating them. Natasha, in a fluid motion, shook the nonexistent blood from her blade and sheathed it with a metallic click that echoed in the empty street.

She looked at her hands. She felt different. Not just stronger or more energized. She felt something fundamental within her, in her Essence, was being rewritten. Power bubbled beneath her skin.

But there was no time to analyze it. A roar snapped her out of her introspection.

"Gah!" The cry was Kyosuke's.

Taking advantage of Kyosuke's distraction from watching Natasha's awakening, Natsuki had concentrated a blast of compressed air with both her fans and launched it point-blank. The impact sent Kyosuke flying like a ragdoll. His body crashed through the brick wall of a nearby building and disappeared into rubble and dust.

With Kyosuke out of the way, the street fell silent again. Natsuki landed softly on an overturned car, shaking her fans elegantly. Her inverted eyes looked at her younger sister with a mixture of genuine surprise and malicious amusement. She began to clap slowly.

"Clap... clap... clap..." "Bravo," Natsuki said, her voice dripping with sarcasm. "My fragile little sister is finally learning to walk on her own. Hahaha... That was an impressive slash. Almost worthy of a general."

Natasha, for her part, didn't say a single word. Her face had become an expressionless mask. All she did was exhale a deep sigh, expelling the hot air from her lungs to calm the whirlwind in her mind. Her mismatched eyes fixed on Natsuki with the intensity of a predator.

Natsuki's smile faltered slightly at that silence. "My... how boring you've become," she said, falling into a low combat stance, snapping her Tessen open with a metallic click. "Very well. Let's see if that newfound confidence helps you."

The second assault began.

This time, it was different. Natasha disappeared. Her speed had increased exponentially. She was no longer a blur; she was a ghost. Natsuki barely had time to raise her fans to block a descending slash that would have split her skull in two.

Purple and black sparks flew. Natsuki grunted from the force of the impact, her feet sinking into the car's roof. Before she could counterattack, Natasha had already moved. She appeared at her right flank. Horizontal slash. Blocked. She appeared behind her. Kidney thrust. Deflected.

They moved in multiple directions at an incredible speed. One moment they were at the street corner, exchanging ten blows per second, and the next they were fifty meters away, atop the awning of a destroyed store. The sound of clashing metal was a continuous roar.

Natasha was dominating. Her katana, imbued with that new, dense energy, was faster than her sister's wind defense. "Tsk!" Natsuki was forced to retreat, jumping backward.

She looked at her kimono. It had multiple thin cuts on the sleeves and side. Small threads of dark blood began to stain the white fabric. "Damn brat..." Natsuki hissed. Her elegant composure was beginning to crack. "You're becoming a real nuisance."

Both stopped for a second, panting in the rain. Natsuki ran her tongue over a cut on her cheek. "You're a very naughty little sister," she said, her eyes gleaming with contained fury. "Damaging our master's gift like this... I'll have to punish you properly."

With that, Natsuki grabbed the collar of her beautiful ceremonial kimono and pulled hard. The fabric tore and fell to the wet ground, revealing what she wore underneath. She no longer looked like a traditional dancer. Now she wore a form-fitting black suit, made of a flexible material that looked like shadow-skin, designed for pure speed and assassination.

Natsuki stretched her neck, making her vertebrae crack. Her dark aura expanded. "Now then. Let's dance for real, little sister... together once more."

They lunged at each other again. The impact of their energies was so strong it cracked the pavement beneath their feet. This time, thanks to Natsuki's brutal charge, the fight moved indoors. They crashed through the window of a giant building, bringing chaos into the marble lobby.

Inside, the space was a labyrinth of concrete pillars and broken escalators. Natsuki used the terrain to her advantage. She jumped from pillar to pillar, bouncing off walls, attacking from blind angles, above and below, trying to overwhelm Natasha with a bombardment of wind slashes from every possible direction.

But Natasha didn't yield. She was in the center of the lobby, pivoting with precision. Block. Parry. Counterattack. Her katana was an impenetrable shield.

However, something was changing. With each blow Natasha blocked, her katana began to shine more intensely. The purple aura surrounding her became solid, almost liquid, covering her body like a second skin. She felt the Regent's Essence that Natsuki was using was resonating with her own, forcing an evolution. Adapting.

"It's useless!" Natsuki shouted from the second-floor balcony, plunging down with both fans open for a final blow. "Die!"

Natasha looked up. Her eyes shone. "No."

She let out a shout that made the remaining glass in the building tremble. "HAAAAAAAAAH!"

All the energy accumulated in her body rushed into her weapon. The katana seemed to grow. The purple aura extended two meters beyond the tip of the blade, forming a gigantic sword of pure, crackling energy.

Natasha spun her body and launched a horizontal slash with the giant weapon. The attack was devastating. The energy wave cut through the lobby's concrete pillars as if they were twigs. It struck Natsuki mid-air. The older sister couldn't block that. The force of the impact hit her squarely in the chest.

Natsuki shot back like a projectile. She crashed through the back wall of the building. Then through the wall of the next building. And the next. The explosion of purple energy carved a tunnel of destruction through three concrete structures before dissipating.

Silence fell in the ruined lobby. Kyosuke, who had just emerged from the rubble where he'd been buried, limped to the building's entrance just in time to see the result. His jaw dropped, and he adjusted his broken glasses.

There, amidst the dust and rain pouring through the broken ceiling, stood Natasha. But she was no longer just Natasha. The energy enveloping her had solidified. Over her torn uniform, pieces of armor made of gleaming black metal with golden edges had materialized. A fitted breastplate protected her torso, segmented pauldrons covered her shoulders, and heavy gauntlets with red details sheathed her forearms. Her purple hair, now loose and wild, floated upward, defying gravity, propelled by the pressure of her power. She looked like a war goddess from a forgotten era. A Kijin General.

"Incredible..." Kyosuke murmured.

Three streets away, amidst a mountain of broken bricks, Natsuki tried to get up. She was wounded. Blood flowed from her head, and one of her arms hung at a strange angle. Her beloved Tessen were dented and twisted. "Damn... where did she get that power?" she spat blood.

She had no time to process it. The ground vibrated.

With a single explosive step, Natasha crossed the distance of three streets in an instant. She landed in front of Natsuki, sending up a wave of water and debris. Without pause, Natasha launched a downward strike. Natsuki barely managed to cross her damaged fans to block.

CRACK! The ground beneath Natsuki sank half a meter. Her knees buckled. Sparks of purple and black power bounced violently where their weapons crossed. Natasha didn't let her breathe. She withdrew the sword and unleashed a rain of thrusts. Natsuki was forced to retreat, desperately dodging, jumping backward, unable to find an opening to attack.

Each of Natasha's blows was faster, heavier, more savage. Kyosuke, who was running to catch up, realized something terrifying. Natasha's impeccable technique was disappearing, replaced by an instinctual brutality. Her growls were no longer human. "Natasha, wait!" Kyosuke shouted. "Be careful! Something's happening to your body, you're losing control!"

"SHUT UP!" Natasha roared without turning. Her voice had a guttural distortion. "I KNOW!"

Her eyes had changed. Her pupils had split vertically, like a cat's hunting its prey. She only saw the target. She cornered Natsuki against the wall of a dead-end alley.

Both sisters were exhausted. They panted, bled, water and sweat mixing on their faces. They stood face to face one last time. They knew the next move would be the final one.

Natsuki screamed, gathering the last shred of dark energy she had left for a suicidal attack with both fans aimed at Natasha's neck. Natasha didn't dodge. She lunged forward in a frontal attack, relying on her new armor and speed.

The world became a flash of light and sound. The weapons crossed. A second of silence.

And then, the sound of shattering metal. Natsuki's Tessen flew to pieces. Natasha's katana, gleaming with a lethal light.

Natsuki fell onto her back on the wet ground. There was no scream. Only the sound of her body hitting the pavement. The cut had been clean, deep, piercing the chest where a human heart once had been.

Natasha stood over her. The rain struck her black armor, which began to flicker, unstable. Natsuki looked at the gray sky with eyes quickly losing their unnatural gleam. "The rain..." Natsuki whispered, her voice weak and gurgling. "It's still cold."

Natasha said nothing. Her chest rose and fell violently. Natsuki slowly turned her head to look at her younger sister one last time. A genuine smile, perhaps the first in years, touched her blood-stained lips. "I'm... proud..." she said with difficulty. "You've become strong, little sister. Very strong."

Natasha felt a lump in her throat but didn't cry. "But..." Natsuki's smile turned mocking again. "That won't be enough. The creatures that come after the Regent... the true monsters... will eat you alive."

"Do you regret it?" Natasha asked, her voice hoarse.

Natsuki let out a laugh that ended in a coughing fit of bloody sputum. "Regret? Killing those insignificant humans?" Her eyes gleamed with malice one last time. "Never. It was fun."

And with that final confession of monstrosity, Natsuki's body began to disintegrate. The edges of her skin turned to gray ash, dissolving in the rain. In a matter of seconds, nothing remained of her. No body, no blood. Only a wet stain on the asphalt.

For Natasha, it was the final blow. She had killed her sister. She had recovered the memory of her family only to have to destroy it with her own hands. The silence of the alley was crushing.

She stared at the empty spot. And then, the price of power arrived.

"Gah!" Natasha's body broke. The excess Kijin power she had forced into her body collapsed. The black and gold armor faded away in wisps of purple smoke. Natasha fell to her knees and vomited a great amount of blood onto the spot where her sister had died.

She felt a cold that reached her very bones. Her breathing was shallow and rapid. Her vision blurred. She felt she was dying too, that her soul was tearing apart from the strain. She was about to fall face-first to the ground when strong arms caught her.

Kyosuke was there. He didn't say a single word. His face was serious, devoid of his usual jokes. With surprising gentleness, he lifted her in his arms as if she weighed nothing and carried her quickly out of the rain, toward the dry shelter of a nearby building, while the storm continued to roar over the city of the dead.