The Gem's voice was a low hum of satisfaction in my head. "Your approach is crude, but effective."
A glowing red line appeared in my vision, a psychic GPS leading me out of the park and toward a seedy-looking building squeezed between a pawn shop and a ramen joint. The flickering neon sign read "KARAOKE HEAVEN."
Aoi scurried to keep up, a mix of hope and fear on her face. "Um, where are we going, Hakuto-san? Is this the studio?"
"This will do," the Gem stated. "Private, soundproof. No one here cares what happens behind closed doors."
I pushed open the door. A bored-looking kid at the counter barely looked up from his phone. The Gem materialized a wad of cash in my pocket. I tossed two crisp bills onto the counter. "Room for two. Two hours."
The kid's eyes widened at the cash. "Right this way. Room 7. End of the hall."
I led a trembling Aoi down the dark, sticky corridor and opened the door to Room 7. It was a small, windowless box with a cracked pleather sofa and a lingering smell of stale beer. Aoi stepped inside, her hopeful expression faltering. This wasn't the glamorous studio she'd imagined.
I stepped in behind her and slid the lock on the door. It clicked shut with a heavy, final sound.
"Alright, relax, Aoi-chan," I said, a cruel smile spreading across my face. "Let's begin the audition."
Aoi clutched her school bag, her knuckles white. "Start what? I don't see any equipment… This place is…" She turned to face me, her sentence dying in her throat as her eyes widened in absolute terror.
The wet, tearing sound of my shirt ripping filled the small room as four thick, shadowy tentacles erupted from my back.
"M-MONSTER!" she screamed, a sound completely swallowed by the soundproofed walls. She scrambled backward, tripping over the low table and crashing onto the sofa. She fumbled inside her bag, desperately searching for her transformation item. "Luminous Sapphire… Meta–!"
Before she could finish, the tentacles surged forward. Two wrapped like vipers around her wrists, pinning them to the sofa above her head. Another two coiled tightly around her ankles.
"Let me go!" she shrieked, tears of terror and rage streaming down her face. "It was a lie! Who are you?!"
"Her spirit is strong," the Gem noted coolly. "This is good. It will make her submission all the sweeter. Break her."
"I wasn't lying about making you shine," I said, my voice low as I approached her. "Become mine, and you'll shine brighter than anyone. Everyone will look at you, Aoi. Not your sister."
My words hit her harder than any physical blow.
"How… How could you know…?" That secret, spoken by this monster in this filthy room, shattered her last line of defense. She stopped thrashing, her body going limp with despair.
The promise of a solo spotlight, of finally eclipsing Akane, was a seed of darkness that had already taken root. From the tentacle holding her right wrist, a tiny, sharp needle extended and pricked her skin. The dark fluid flooded her system. A violent shudder racked her frame, and a low, confused moan escaped her lips.
"The flesh submits," the Gem declared. "The will follows. Corrupt her."
I knelt beside her, the Black Gem cold in my hand. With a single, brutal motion, I tore her school uniform open, exposing her chest. The faint blue glow of her magical core pulsed over her heart, a soft, frightened light.
"You wanted the spotlight, Aoi," I whispered, hovering the Gem just above her skin. "You wanted to outshine your sister. Your transformation is about to be complete."
I pressed the Gem against her core.
Aoi screamed, a sound of pure agony and overwhelming pleasure as the darkness poured into her. A shadowy aura erupted from her body, swirling like a storm in the tiny room. Her school uniform dissolved into black smoke, reforming into a new, twisted magical girl costume. It was a cruel mockery of her original outfit—the sleek sailor uniform was now black leather, cut dangerously low. The silver trim was a tarnished, gunmetal grey. The sapphire on her chest was now a black, star-like crystal that seemed to drink the light from the room.
The tentacles retracted, slithering back into my body as if they were never there. She lay on the sofa, panting, her transformation complete. Slowly, she pushed herself up, her movements no longer frantic, but deliberate, filled with a new, predatory grace.
She looked at her leather-gloved hands, then down at her new form. There was no horror on her face. Only a slow, dawning realization that morphed into a terrifying, cold smile.
"This power..." she said. Her voice was the same, but the strained professionalism was gone, replaced by a smooth, chilling confidence. "It feels… correct." She looked at me, and her eyes, now a deep, hypnotic indigo, held no fear. Only calculation and a chilling, newfound loyalty.
"There she is," I said with a smirk, leaning back in a chair. "So, the offer still stands. I'll make you a star." I grinned. "Now, come here. Tell me about your new powers."
A cold, knowing smile spread across Dark Sapphire's lips. She flowed off the grimy sofa with a liquid grace, her new leather boots making no sound on the sticky floor. She didn't just walk over to me; she glided. She sank to her knees before my chair, her movements practiced, as if she'd been doing this her entire life. She rested a gloved hand on my knee, her touch both a submission and a claim.
"To serve you is my pleasure, Master," she purred. "You've given me what I always craved but was too weak to take for myself. As for my power… 'Luminous Sapphire' was a shield. A shared, weak light meant to protect. So tedious."
She held up a hand, and a small, shimmering sphere of darkness materialized, draining the tacky light from the karaoke machine's screen.
"I can create zones of absolute darkness, blinding my enemies. But my true gift…" A cruel, beautiful smile spread across her face as the full implication hit her. "I can now drain the energy from others. Their confidence, their magical power… even their will to fight. I draw it into myself, and it makes me stronger."
She looked up at me, her eyes gleaming with a lifetime of repressed ambition.
"Imagine, Master. Standing next to Akane on a battlefield… and I can just… take her light. Leave her a dim, flickering candle while I become a supernova. I will finally be the star. The only star."
She was my perfect weapon, forged from envy and desire.
"That could be useful," I said, patting her head. "Bring your sister here. It's time for her audition, too."