From a distance, atop the ruined remains of a collapsed structure, a lone Soul Reaper observed the battlefield with sharp, calculating eyes. His jaw-length blonde hair hung motionless in the air, untouched by the weak breeze that whispered through the wreckage. His brown eyes, normally half-lidded with an air of casual indifference, were hardened with frustration, his usual smirking demeanor replaced with a clenched jaw.
Draped over his shoulders was the long-sleeved white haori of the 5th Division Captain—a stark contrast to the soot-stained black of his shihakushō. His fingers twitched at his sides, fists clenching and unclenching as he took in the destruction laid out before him.
Shinji Hirako, one of the prominent members of the Gotei 13 , seethed with quiet fury. Everything had unraveled so fast.
One moment, they were maintaining order in Soul Society , and the next, the Wandenreich had torn through their ranks like wolves through helpless prey. Quincies . From the brink of extinction, they had returned—not just as stragglers or remnants, but as an overwhelming force.
And now—
Head-Captain Yamamoto was dead.
The thought alone sent a fresh wave of frustration surging through him.
"Ah… this is such a drag," Shinji grumbled, his voice laced with bitterness as he and his lieutenant walked solemnly through the broken remains of Seireitei , scanning the ruins for survivors.
His footsteps crunched against the dust-covered debris, but his mind was far from the task at hand.
"They really got us good with this farce," he muttered, his voice darkening. "Hell, they even killed the Head Captain, and where was I? Running around like an idiot while everyone else was fighting for their damn lives."
His anger boiled over.
Shinji's clenched fist slammed into a half-standing wall beside him, shattering it into a cloud of dust and rubble.
Momo Hinamori, his new lieutenant, flinched slightly at the sudden display of rage but quickly regained her composure.
"Captain Hirako, please—calm down," she urged, placing a tentative hand on his sleeve. "No one is at fault here. None of us could have foreseen that they were powerful enough to overwhelm us."
Her words were meant to console, but they did little to ease the fury that twisted in his gut.
The battlefield was silent save for the occasional groans of the wounded and the distant echoes of collapsing buildings.
Then—
A pulse of spiritual pressure sent a sharp jolt through Shinji's body.
His eyes narrowed.
That presence—
Isn't that… Tachikaze?
Shinji's muscles tensed.
Kensei .
If his zanpakutō had been released, then it could mean only one thing— He's in a fight.
And not just any fight.
If Tachikaze's power was flaring, then the enemy was strong. Too strong for Kensei to hold back.
Shinji didn't hesitate.
"Momo, take over," he ordered abruptly, his tone leaving no room for argument.
His lieutenant blinked. "Understood, but where are you—?"
"Kensei's in a pinch. I'm going to help."
Momo hesitated but nodded. "…Be careful."
In the next instant, Shinji vanished.
A burst of wind scattered dust where he once stood as he propelled himself forward with a Flash Step, covering vast distances in mere seconds.
As he moved, his mind worked rapidly to piece the situation together.
Kensei wouldn't use his Shikai unless the opponent was serious. If he went as far as to release his Bankai… then this isn't just some random leftover Quincy.
It's someone tough as hell.
If we can capture them, we might finally get some answers.
Then—
A blinding flash tore through the battlefield ahead.
Shinji's pupils shrank.
A shockwave of violent wind exploded outward from Kensei's position, tearing through buildings and scattering debris like paper in a hurricane.
That was… Bankai?!
Shinji's chest tightened.
Shit—hasn't he heard that they can steal our Bankai?! What the hell is he thinking?! He forced more speed into his next Flash Step, his body becoming a blur of motion. But before he could process another thought—
A massive blast of wind slammed into him.
The force hit like a wrecking ball.
Shinji barely had time to cross his arms in defense before the shockwave hurled him backward, tearing through his haori and ripping into his skin like invisible blades.
He twisted mid-air, gritting his teeth as he fought to stabilize himself, but the sheer pressure behind the gust sent him careening through the air like a ragdoll.
Then—impact .
His back slammed into a partially destroyed building, cracking the structure upon impact. The force of the collision sent fresh pain jolting through his spine, but he barely had time to register it.
The moment his feet hit the ground, he bent low and skidded backward, boots grinding against the shattered pavement as he finally came to a stop.
A heavy silence followed.
Dust and smoke billowed around him. His haori fluttered in the dying remnants of the windstorm.
Shinji let out a sharp breath, his body tensed, every nerve screaming at him to stay on guard. His eyes snapped toward the battlefield ahead.
The air was thick with spiritual pressure.
And at the very center of it—
Two monstrous forces clashed.
One was Kensei.
The other…
Shinji narrowed his eyes.
The battlefield was silent for a moment, the dust slowly settling in thick, lazy clouds, but the tension hung heavier than ever. Shinji, still shaking off the force of the shockwave, pushed himself forward in a burst of Shunpo , his senses on high alert.
His eyes darted over the wreckage—then stopped.
Kensei was kneeling, his right arm barely recognizable. Deep gashes carved into his flesh, skin nearly peeled away to expose raw muscle and bone. His knuckles were shredded, his fingers trembling as he barely managed to clutch his ruined arm.
Shinji's breath hitched.
Kensei Muguruma was a warrior through and through. He didn't flinch in battle, didn't hesitate, didn't break under pressure. Yet now—he was barely holding back a scream of agony.
And standing before him, as if the battle was already decided, was the man responsible. Alex Mercer.
His right arm was gone—ripped away from the impact of Kensei's Bankai. But what should've been a crippling injury didn't seem to faze him. He merely turned away, indifferent
to his own missing limb.
"I told you," Mercer muttered, his voice eerily calm, "I warned you."
Then it happened.
Dark, writhing biomass pulsed from the stump of his missing arm, bubbling and shifting like something alive. The flesh knitted itself back together, growing outward until, in mere seconds, his arm was whole again.
Kensei's breathing turned ragged, his face twisted in disbelief.
Shinji had seen regeneration before—Hollows, Arrancar, even certain Shinigami had ways to heal rapidly—but this? This wasn't just regeneration. It was a reconstruction.
He swallowed down his unease and stepped forward, katana drawn.
"What the hell happened here?" he muttered under his breath, taking in the sheer destruction around them.
Then he saw Kensei's expression—one he had never seen from him before. Not frustration. Not anger.
Fear.
The kind of fear that sent a chill crawling down Shinji's spine.
Ahead, Mercer began walking away, moving with an almost casual ease, like this was just another step in his day.
Shinji leveled his sword at him. "I wouldn't take another step if I were you."
Mercer barely spared him a glance. "Don't bother," he said, voice laced with disinterest. "Unless you want to end up like your turd-haired friend over there."
Shinji's grip on his katana tightened. This guy…
"Now tell me how I get out of here," Mercer added.
Shinji's jaw clenched. His attitude, his actions—it was like he had completely forgotten that he just tore Kensei apart.
"You sure have a sharp tongue, oji-san ," Shinji quipped, shifting into a stance. "Let's see if you've got a sharp sword hidden there too."
Before he could make a move, Kensei's bloody hand clamped onto his arm. "Don't provoke him, Shinji." His voice was tense, urgent. "We can't beat him."
Shinji shot him a sideways glance. "Then we'll just wait for backup and pin this Quincy down."
"He's not a Quincy!!"
Shinji froze.
The words hit him harder than he expected.
His mind reeled. If he wasn't a Quincy… then what the hell was he?
A face flashed in his mind—a man with a hole in his torso and a tattooed '6' on his back. "…Then he's an Espada?"
"He's not a Hollow either."
A heavy silence hung between them.
Shinji's brows furrowed. If he wasn't Quincy, and he wasn't Hollow, then— What is he?
His thoughts warred against each other. On one hand, Mercer had just mutilated a fellow Captain. He was a direct threat and needed to be taken down. But on the other hand, attacking someone they knew nothing about was suicide.
Kensei wasn't the type to back down from a fight. For him to tell Shinji to stand down… That was enough.
Shinji exhaled, loosening his grip.
"…Tch. If it can't be helped, then…"
He sheathed his blade with a sharp click .
Mercer smirked. "Good choice," he said mockingly. "I've had just about enough of beating your kind to a bloody pulp."
Shinji's patience was already running thin.
"Don't act like you're so damn remorseful after tearing Kensei apart," he shot back. "You're lucky I'm not the type to strike without thinking. Unlike that big lug over here."
"Oi—who the hell are you calling a big lug?!" Kensei barked.
Mercer scoffed. "And I wouldn't have had to if he didn't try to piss me off." He turned slightly. "Now, tell me how I get out of here."
A slow, knowing grin spread across Shinji's face.
"Oh, it's simple…" he mused, slowly twirling his katana. "Just gotta figure out which way is up, down, left, or right."
The air around them shifted.
Mercer's body lurched.
His vision blurred. His stomach twisted violently as an overwhelming sense of vertigo slammed into him.
His knees buckled. His head spun.
What—what the hell was—?
Shinji stood there, a smirk tugging at his lips.
"Welcome to the Upside Down World."
The scent from his sword's five holes had already taken effect. Mercer's senses were completely scrambled. Up was down. Left was right. Attacks came from where they shouldn't. His entire perception of the world had collapsed in on itself.
There was no adapting. No escape. No counter.
Even the strongest opponents fell prey to it.
Shinji took a slow step forward, blade gleaming.
"Troublesome bastard," he muttered. "Let's put you down—"
Then he stopped.
Something was wrong.
Mercer's body was changing.
Dark biomass fluctuated across his skin, pulses of black and red flickering faster and faster, like a heartbeat growing erratic.
Shinji's instincts screamed at him.
"SHINJI, GET AWAY FROM HIM!!"
Kensei's warning came just in time.
Shinji vanished in a blur of movement.
Then Mercer exploded.
Barbed tendrils erupted from his body, lashing out in every direction. The air cracked with the sound of flesh and bone being impaled. The surrounding ruins were torn apart, and the
unfortunate souls caught in the blast—Soul Reapers who had only just arrived—were snatched up, their bodies consumed in an instant.
Shinji barely landed a safe distance away, his breath coming in sharp, measured gasps. "What… the hell is this guy?" he muttered.
Kensei wiped blood from his lips, eyes burning with frustration.
"I told you," he growled, "not to provoke him."
Mercer straightened, his body fully restored from the tendrils' rampage. Then he moved.
In one powerful leap, he launched himself toward a massive, gatelike structure. Shinji's eyes widened.
The Senkaimon.
Kensei, despite his injuries, forced himself forward.
Shinji followed suit, but stopped cold.
His breath caught in his throat.
Before them, Mercer's body twisted again—dark tendrils coiling around him— And in the next instant, he wasn't Mercer anymore.
A Soul Reaper stood in his place. Indistinguishable from the others.
A devious smirk lingered on his lips as he disappeared into the crowd. Shinji's stomach dropped.
"…Damn it," he muttered, fists clenching.
Kensei let out a slow, exhausted breath. "One moment he's fighting us," he muttered, "the next he's walking among us."
Shinji's lips curled downward.
"What a damn day to be a Soul Reaper."
The Senkaimon stood tall, its white light piercing through the darkened skies of Soul Society. Amidst the growing unease, the Kido Corps practitioners remained on high alert, their disciplined ranks forming an unbreakable wall of defense.
Then came the lone Soul Reaper—panting, breathless, his uniform tattered, drenched in sweat as he stumbled toward them. His voice was frantic, strained from exhaustion.
"Reports of Quincies… appearing in the Human World… Please, open the gate… I need to confirm if the reports are true…"
One of the practitioners hesitated. "But we need the approval of—"
A fist clenched his collar in a desperate grip, yanking him forward. The supposed Soul Reaper's eyes burned with an unsettling urgency.
"God damn it, Commander Yamamoto is dead ! There's no time for approval!" The words hit like a hammer. The hesitation evaporated instantly.
"R-Right away!"
With hurried hands, the practitioners activated the Senkaimon, the ancient gateway groaning as it parted the very fabric of reality. A blinding white glow erupted outward, illuminating the area. The lone Soul Reaper took a step forward—
Then stopped.
A single voice cut through the tension.
"Wait… You don't have a Jigokuchō on you."
Silence.
The air grew heavy. Even the flickering flames of the Kido lanterns seemed to waver, as if disturbed by the stillness.
The Soul Reaper's face twitched. His lips barely parted as a single, vacant word slipped out. "A… what?"
The Kido Corps knew. They all knew. No Soul Reaper could traverse the Dangai without the Hell Butterfly. And yet, this one—
"Everyone, surround him!"
Bodies moved in unison, the air crackling with spiritual pressure as the Kido Corps formed a tight circle. Hands raised, energy coalesced between their palms as one of them muttered a binding spell:
"Bakudō #4: Hainawa!"
Golden energy surged forward, a crackling rope of reiryoku lashing out and ensnaring the impostor's arms and torso in a tightening bind. His body jerked from the force, feet nearly leaving the ground.
Yet, he did not struggle.
A smirk curled upon his lips, shadowed by something inhuman lurking beneath his expression.
"Damn it… to think that a mere butterfly gave me away." His voice was no longer frantic. No longer desperate. It carried a weight—cold, detached, predatory .
Then the horror began.
A sickening, wet squelch echoed through the air as an ooze of black and crimson began seeping from his eyes, his nostrils, his very pores. Thick, pulsating tendrils slithered from beneath his flesh, twisting and writhing like living veins breaking free from their prison. The Kido Corps practitioners froze in place, their eyes wide with pure terror.
"W-What the hell is that?!" one of them gasped.
As the ooze consumed him, the false Soul Reaper's body melted into a grotesque mass of biomass, shifting and reforming into something far more monstrous . The bones cracked, reshaping. Skin peeled away, replaced by writhing black tendrils. His form grew , muscles surging outward, a grotesque blend of human and something far beyond comprehension. And then—
He stood before them once more.
No longer a Soul Reaper. No longer hiding.
Alex Mercer.
A hulking, deathly figure wrapped in a hooded grey jacket, his piercing eyes glowing like molten coals beneath the shadow of his hood.
His gaze flickered downward—toward the glowing energy of the Hainawa rope still binding him.
"Such an interesting power…" he murmured, stretching his fingers outward. The tendrils along his arm twitched, pulsing with life as they latched onto the reiryoku rope.
The yellow energy began decaying . Or rather, it was being consumed .
The energy corrupted, turning from golden light into something sickly black and red. Before the Kido Corps practitioner could react, his own spell betrayed him . The rope surged backward—straight to its caster. The energy twisted, morphing into a grotesque tendril that latched onto his arms, restraining him instead.
His horrified eyes darted to Mercer, who merely tilted his head.
"You shouldn't be so careless."
The next instant, Mercer yanked the tendrils toward him.
The practitioner hurtled forward.
Mercer's right hand morphed—twisting, elongating into a monstrous, blade-like claw.
SHLKK.
The practitioner never even screamed.
His body convulsed as Mercer's claw buried deep into his gut, tearing through flesh, organs, and bone with sickening ease. Blood splattered across the white stone beneath them.
Then Mercer grabbed his face with his other claw.
Three sharpened fingers sank deep—through his eyes, through his skull, piercing straight through the back of his head. His body twitches violently, mouth gaping in silent horror, before it was swallowed—consumed—by the writhing biomass tendrils wrapping around Mercer's arm.
The rest of the Kido Corps practitioners could only watch in pure horror. "Y-You… MONSTER!" one of them shrieked.
More hands lifted. More incantations chanted in unison, voices trembling but desperate.
"Ye lord! Mask of blood and flesh, all creation, flutter of wings, ye who bear the name of—"
Mercer sighed.
"I've had enough of your little tricks . "
Then he slammed his claws into the ground.
The earth convulsed.
A grotesque, inhuman tremor rippled outward, followed by the sound of flesh tearing free from the world itself.
Then—
Spikes .
Massive, writhing, black-red SPIKES erupted from below.
SHLKT! SHLKT! SHLKT!
It was over in an instant .
The chanting stopped.
Nearly all of the Kido Corps practitioners were impaled . The deadly biomass tendrils had pierced straight through them, rising high into the sky, their bodies twitching like grotesque marionettes before slumping into stillness .
Mercer exhaled, standing amidst the sea of skewered bodies, his crimson eyes burning like embers.