Chapter 20:

Cantus Null: Residue (Part IV)

The Blessing of Diva: Resonance Zero

[November 27th, 12:30 JST]

Tochigi Prefecture – Abandoned Industrial Zone

Static crackled in Reina’s earpiece before a voice pierced the noise.

“Tempesta Unit, report. We lost your signal for nearly fifteen minutes,” Takeshi said, urgency barely contained. “What happened out there?”

Reina lowered her gaze, exhaling slowly.

“Producer... it’s done,” she replied in a quiet voice. “Request immediate medical evacuation to my position. Mika’s badly injured. Some of us are barely holding on. The rest will proceed with the initial objective.”

As she spoke, her eyes flicked to the side. Emiko was already kneeling beside Mika, her palm glowing with a faint Lux sigil as she worked to seal open wounds in a careful and controlled manner. It was enough to stop the bleeding. Not enough to fix what was broken beneath.

There was a brief pause on the other end.

“...Roger that,” Takeshi said. His tone softened. “I’ll have med teams en route. I expect a full report once you’re back.”

A long, weary exhale crackled through the line.

“Be careful.”

Reina turned as the line went quiet, scanning what remained of her team.

“Emiko, stay with Mika. Keep her stable until evac arrives,” she ordered. “Misaki, you’re staying too. You’re in no condition to continue. Nana—watch over them.”

She shifted her focus.

“Momoko. Emi. Yuzuriha. You’re with me.”

Mika let out a weak, crooked smile as Emiko worked.

“Sorry, Reina-senpai,” she muttered. “Guess I’m not much help now.”

Reina shook her head, a small smile returning.

“You saved us a lot of time just now,” she said. “That’s more than enough.”

She gestured forward, and without another word, jogged toward the collapsed compound. The three girls fell in behind her, their footsteps crunching softly over broken concrete as they moved deeper into the ruined building.

The interior of the building was wider than Reina expected, but far darker. Corridors branched into wings and unknown passages, their depth swallowed by shadow.

Emergency lights flickered weakly along the main hall, red glow cutting across collapsed concrete and hanging cables left by the failed Coda Cantus explosion. The air felt wrong, a lingering pressure of resonance burned into the walls where cult symbols had once been painted.

As they neared the inner section of the compound, the signs of combat appeared.

Reina slowed. Emi and Momoko followed close behind, footsteps light but uneven. Yuzuriha brought up the rear, quiet as ever.

They hadn’t gone far before Reina saw it.

A body lay slumped against the wall. The lower half was simply gone, not torn. It was erased as if the space where it should have been no longer existed. The rifle beside him ended the same way, its barrel cut short mid-length, edges unnaturally smooth.

Reina knew immediately whose work it was.

“...He didn’t even get a chance,” Momoko murmured.

Emi swallowed hard but said nothing.

Further down the corridor, more bodies came into view.

Several JSDF soldiers lay where they had fallen, uniforms scorched black. Some still clutched their rifles, fingers locked tight even in death. Spent casings littered the floor around them, useless against what had charged through.

And then there were the others.

Small piles of sand lay scattered across the concrete, gathered where people should have been. A rifle rested beside one. A dog tag glinted faintly in the emergency light, half-buried in the grains.

Reina knelt beside the first soldier and removed his tactical mask. His open eyes were glassy and unfocused, reflecting the dull red glow above. Dried blood stained the wall and pooled beneath him.

Yuzuriha’s voice came softly from behind.

“...Yuzu feels sorry for them.”

She didn’t look at the body. Her grip tightened around the D-Mic, knuckles whitening as her gaze stayed fixed on the floor.

Reina pressed her earpiece.

“Lieutenant Morita,” she said quietly. “We found your missing men. No survivors.”

She paused.

“They were engaged before CODA escalation. The attackers weren’t standard combatants.”

The channel stayed silent for a moment.

Reina lowered her gaze, listening to the faint hum of emergency power in the ruined corridor.

“Understood,” she said at last. “My condolences.”

She released the earpiece and exhaled slowly.

Reina then lifted her hand and signaled forward. The team moved again, following the faded cult markings etched along the wall — simple, jagged lines carved again and again, like a broken staff split down its length.

The symbols led them to a set of double doors at the end of the hallway.

They were heavier than the others, reinforced steel with warning placards half-scratched away. A low, oppressive tension could be felt radiating from inside even before the handle was touched, like resonance trapped with nowhere left to go.

Reina took a breath and pushed.

The room beyond was a laboratory. Stainless tables lined the center of space, cluttered with glass containers, IV stands, syringes, and racks of instruments Reina didn’t recognize. Refrigeration units purred along one wall, each marked with handwritten labels. Cables ran across the floor and up into the ceiling, threaded through crystal conduits etched with faint sigils that pulsed only when they stepped closer.

Reina recognized the crystals immediately.

Novium.

A chill ran through her. This wasn’t scavenged residue or black-market scrap. Someone had given the cult access to meteor-grade Novium.

At the far end of the lab was another door — smaller, plain. Reina and the others crossed the room and opened it slowly.

Inside were five beds.

They were arranged in a row, evenly spaced with white sheets pulled tight. Each bed had an IV stand beside it. Each headboard bore a small strip of tape with a handwritten name.

A school bag rested beneath one bed.

A folded uniform lay on another.

Emi, silent until now, let out a sharp, stifled breath. Momoko’s expression tightened, caught somewhere between anger and disbelief. Yuzuriha glanced inside once, then turned away, unwilling to linger. She paused near the doorway, slipped a few pills from a small bottle, and swallowed them without water.

Reina scanned the room quickly.

There was no grief — not exactly.

Just a dull weight. The kind that came from knowing you had fought someone you might have saved, and now standing in the place where they had lived instead.

Emi touched her arm, pulling her back.

Reina stepped out and closed the door.

Back in the lab, Momoko and Emi spread out instinctively, examining the equipment. Yuzuriha lingered near the doorway, gaze drifting across the room, her grip on the D-Mic steady but tense.

Reina wanted to say something — anything — to break the pressure hanging over them. But nothing came. Even Momoko stayed quiet.

The room didn’t allow for words.

Her attention was drawn to a terminal left powered on. Papers were scattered beside it. The placement felt deliberate, as if someone had wanted them found.

A single file sat open on the screen.

Reina hesitated, then tapped it. Her blood ran cold.

Five entries filled the display.

She recognized the faces immediately. The only new information was their names and ages. Beneath that ran lines of technical documentation she didn’t fully understand.

Every entry ended the same way.

Status: Stabilized.

Condition: Behavioral compliance achieved.

Disposition: Post-incident transfer approved.

Reina’s fingers tightened against the edge of the desk.

Reina closed the file.

“What is it?” Emi asked quietly.

Reina shook her head.

“Something you don’t need to see,” she said, and turned away.

The cult marking didn’t stop at the lab. They continued down a short corridor beyond it, carved deeper into the concrete, the lines rougher and more hurried. With every step forward, the air grew heavier, as if the space ahead had been tuned to a frequency the body wasn’t meant to endure for long.

The corridor opened into a wide chamber.

Almost the size of a basketball court. And nearly empty.

The four walls were completely covered in runic symbols, layered and overlapping, carved with obsessive precision. Loudspeakers were mounted high in each corner of the room, angled inward. There were no platforms, no ritual circles, no ornamentation. Just bare concrete and symbols meant to be heard rather than seen.

At the far end of the chamber stood a device.

It resembled an industrial generator. Thick cables were anchored into the floor, coils stacked in concentric rings, metal panels with hastily drawn runes. At its core, suspended between stabilizers, floated a fragment of Novium the size of a clenched fist.

It was resonating.

Reina felt it in her chest before she understood it. Not pressure pushing outward, but something tighter, invasive. The resonance scraped against her own, disrupting the frequency inside her. Her breath shortened without her noticing.

So this is it.

Momoko swallowed. “Is... that—” She stopped, a hand pressing briefly to her temple. The contamination in the air made it hard to focus, hard to speak.

Emi shifted uncomfortably, shoulders tense. Even Yuzuriha’s expression tightened, her fingers curling around her D-Mic.

“Yes,” Reina said quietly. Cold sweat slid down her back. “I think it is.”

The chamber responded as if acknowledging Reina’s words.

A soft click echoed, followed by a low mechanical hum that slid into the room. The runes carved along the walls answered, faint light crawling through their lines as the frequencies aligned.

The device stirred.

The air thickened with distortion. Reina felt it immediately. The same unease rippled through the others.

Then the speakers activated.

“Good,” a man’s voice said calmly. “You arrived on schedule.”

Reina raised her D-Mic at once, eyes sweeping the chamber. “Show yourself.”

A brief pause.

“There’s no need,” the voice replied. “You’re already standing where I require you.”

The Novium core pulsed.

Black mist bled from the corners of the chamber, drawn inward by the device’s rhythm. It gathered along the floor, coiling and shaping itself with unnatural patterns.

Forms emerged.

Things Divas had always fought. Never imagined controlled.

Level 1 and Level 2 CODA took shape across the chamber, one after another, surrounding Reina and her team. Yet they did not charge. They stood where they formed, red eyes fixed forward, waiting.

Emi’s grip tightened on her D-Mic.

“They’re not—”

“Attacking,” the voice finished. “Correct.”

The device continued its steady whir.

“This is not containment,” the man paused. “It is a controlled transmission environment.”

The CODA shifted. Movement stuttered. Some froze mid-motion, as if receiving conflicted instructions.

“These creatures are expendable,” the voice said evenly. “Their behavior is not.”

Reina stepped forward. “Turn it off.”

“That would invalidate the data,” he replied. “The system is functioning within expected parameters."

The Novium fragment brightened briefly, then settled.

“Proceed as you normally would.”

Reina’s gaze hardened. “You want us to clear the room.”

“Yes.”

“When the chamber is empty,” the voice continued, “I will submit to custody. You may arrest me. Interrogate me. Dismantle my work.”

The CODA shifted again, hesitation sharpened into tension.

“I am not measuring your strength,” the voice said quietly. “Only the outcome.”

A single pulse rippled through the device.

The CODA surged forward, any trace of hesitation vanishing.

Reina and the others wasted no time. Their voices rose together, strained but steady.

“Ars Aria: Fulminare Cantus.”

“Ars Aria: Silentia Cantus.”

“Ars Aria: Aqua Cantus.”

“Ars Aria: Ventus Cantus.”

Reina’s Cantus Veil still held, but it flickered weakly. Exhaustion gnawed at her focus. Around her, sigils and musical tattoos wavered, struggling to maintain form.

Except for Yuzuriha. Her glow was stable.

“Senpai... allow Yuzu,” she said softly.

Her voice rose, not louder, but truer. A gentle shift rippled outward as pink sigils bloomed around the team. The crushing weight in the air lifted at once.

The CODA froze mid-motion.

As if the command holding them together had been rewritten.

Reina didn’t hesitate.

Lightning crashed down. Water surged. Wind tore through the mist. The immobilized CODA fell one after another, the hordes collapsing without resistance.

When the last one dissolved, the device fell silent. The oppressive resonance vanished, leaving the chamber empty and still.

A door opened behind them.

A middle-aged man stepped into view, a long scar running from his right eye to his cheek. He raised both hands without a word, knelt, and placed them behind his head.

There was no resistance or hesitation.

Reina watched him for a long second, searching his face for something.

There was none.

“Secure him,” she said, anger threaded into her voice.

Momoko moved first, binding his wrist with a cable she pulled from nearby debris. Emi followed, scanning the chamber, her gaze lingering on the now-silent device. Without its resonance, it looked almost ordinary. Just metal and wiring.

Yuzuriha stood beside Emi, eyes fixed on it as well.

Bootsteps echoed from the corridor.

Foundation personnel entered in pairs, weapons lowered but ready. Medical staff followed close behind, attention immediately drawn to the runes carved into the wall and the Novium core suspended at the heart of the machine.

Takeshi came in last.

His gaze swept the chamber once before settling on Reina.

“...You lost contact,” he said quietly.

Reina nodded as a medic knelt beside her, bandaging the cuts along her arms and temple. “Interference,” she replied. “It’s over now.”

Takeshi exhaled, then turned to the kneeling man as he was pulled to his feet. “So this is him.”

The cult leader didn’t respond as he was led out.

Emi stepped closer to Takeshi, voice low.

“The device... it’s real. What will this world become if this spreads?”

Takeshi didn’t answer. He didn’t have one.

As more personnel filled the chamber, Reina glanced at Takeshi and allowed herself a small smile. For the first time since entering the compound, the tension in her shoulders loosened.

Not relief. Just... completion.

“Let’s just breathe for now,” she said gently. “The future can wait until we’re home.”

Her gaze drifted to Yuzuriha. She was still standing near the device.

***

The forest bordering the industrial zone lay in deep shadow, the canopy choking out most of the afternoon light.

Bootsteps stumbled through the dry leaves.

Three figures burst through the trees, lab coat torn, breath ragged. One slipped and nearly fell, catching himself against a trunk with shaking hands.

“We’re clear,” one of them gasped. “They’ll be busy with our leader—”

The sound cut off.

A song wafted through the trees.

“Ars Aria: Fortis Cantus.”

Something tore through the air.

A wooden branch struck the man’s forehead with explosive force, punching straight through and pinning him to the ground behind. The sound came a heartbeat later — a sharp and hollow whump.

The second man screamed and ran.

“Ars Aria: Glaciem Cantus.”

A sigil manifested beneath his feet. Ice surged upward, locking him mid-stride. A shadow approached, still singing, and drove a heavy kick into the frozen mass.

Ice shattered. And so did everything inside it.

The third collapsed to his knees, hands raised, words tumbling out—

He never finished.

A second shadow appeared behind him. A sigil flared along her leg. The kick landed clean.

The sound was wet.

The two Team 01 Divas stopped singing, and silence returned.

“Cinderella,” one said calmly, “your Fortis Cantus is effective. But you could be more elegant.”

Cinderella scoffed as she tapped her earpiece.

“Producer. Snow White and I are done.”

They moved deeper into the forest, collecting the scattered papers as instructed, and vanished into the trees.

***

“Yuzu-chan,” Reina said. “You alright?”

Yuzuriha blinked, as if pulled back from a distant thought. She smiled softly.

“Yuzu is fine, senpai.”

The answer came a fraction slower than usual.

Reina nodded and turned away, giving Yuzuriha’s shoulder a brief tap as her thoughts shifted ahead — reports, debrief, the meetings waiting back at the Facility.

She didn’t see Yuzuriha step back, retreating to the edge of the room where the Foundation’s voices blurred into background noise.

She took out her phone.

The call connected after a single tone.

“Yes,” she said softly. “The test concluded successfully.”

A pause.

“The device performed as expected.”

Another pause. Longer.

“Yuzu understands.”

Her grip tightened slightly around her device.

“...I will remain with Reina’s unit, as instructed.”

Silence on the line.

Her gaze lowered.