Section 1: Mangetsu's Search for Yui

The city of Musutafu pulsed with an eerie stillness as night swallowed the streets. Neon lights from closed shops flickered weakly, their glow casting distorted shadows against the rain-slick pavement. The air was thick, heavy with the dampness of the recent storm and the faint metallic tang of pollution. It clung to Mangetsu Kodai's skin as he moved through the labyrinthine alleys, his mind a whirlwind of worry and determination.

Yui's disappearance had left a gaping hole in his chest, an ache that only sharpened with every passing moment. She was his daughter, his light in a world darkened by corruption and danger. Mangetsu's breaths came in measured rhythms, each one a mantra of focus. Find her. Bring her home. No matter the cost.

The tip he'd received earlier that day had led him to the industrial district, a decaying maze of abandoned warehouses and rusting machinery. The place reeked of oil and mildew, the air stale from years of neglect. It was the kind of place where secrets festered, where whispers of stolen children and hidden deals lingered in the shadows.

Mangetsu's hero costume was concealed beneath a dark trench coat, his hood pulled low to obscure his face. He wasn't here to announce his presence. Tonight, he wasn't Bitsize, the pro-hero known for his cunning and adaptability. Tonight, he was a father hunting for his child.

The Art of Silence

The warehouse loomed ahead, its rusted steel doors hanging ajar. Mangetsu paused, his sharp eyes scanning the perimeter. A faint flicker of light shone from within, a sign of activity where none should be. His instincts screamed at him to be cautious.

He shrank down to the size of a mouse, his quirk activating with a faint hum of energy. The world around him expanded into a daunting landscape of towering obstacles and endless shadows. The ground beneath his feet was a mosaic of grime and cracked concrete, each crevice now a potential hiding spot for danger.

Moving with the precision of a predator, Mangetsu slipped through the gap in the doors, his tiny form nearly invisible in the dim light. The interior of the warehouse was a cavernous void, filled with the skeletal remains of old machinery and stacks of decaying wooden crates. The faint hum of a generator echoed through the space, mingling with the distant drip of water from a leaking pipe.

Mangetsu's senses were heightened in his shrunken state. He could hear the scuttling of rats in the corners, the faint rustle of fabric as someone shifted their weight nearby. He could smell the acrid tang of gasoline and the faint coppery scent of blood.

Clues and Frustration

He scaled a nearby crate, his tiny hands finding purchase on the rough wood. From his vantage point, he surveyed the room, his sharp eyes searching for any sign of Yui. A discarded scarf lay crumpled near the far wall, its bright color standing out against the muted tones of the warehouse.

Mangetsu's heart clenched as he leapt down, returning to his normal size in a fluid motion. He knelt to pick up the scarf, his fingers brushing against the soft fabric. It was hers—he'd recognize it anywhere. But it was stained, a dark smear of blood marring the vibrant pattern.

His grip tightened, anger flaring in his chest. They hurt her. Whoever took her, they'll pay for this.

He pocketed the scarf and rose to his feet, his movements sharp and deliberate. The faint sound of footsteps echoed from the upper level, drawing his attention. He moved toward the metal staircase, each step deliberate and silent.

As he climbed, the air grew colder, the faint metallic scent of blood growing stronger. His breath misted in the frigid air, and a chill ran down his spine. The sensation was more than just the cold—it was the unmistakable feeling of being watched.

A Predator's Warning

Mangetsu froze at the top of the staircase, his instincts screaming at him to stop. The shadows ahead seemed to ripple, the darkness taking on a life of its own. A low, almost imperceptible sound reached his ears—a sharp inhale, as if someone was savoring the scent of prey.

"Bitsize."

The voice was low, gravelly, and laced with menace. It seemed to come from everywhere and nowhere, reverberating through the empty warehouse like a sinister echo. Mangetsu's heart pounded in his chest as he scanned the shadows, his eyes searching for the source.

"Do you know what happens to heroes who forget their purpose?" the voice continued, closer now.

Mangetsu turned sharply, his hand instinctively moving to the hilt of the collapsible staff at his side. But the figure emerged from the shadows before he could react, his presence a sudden, oppressive force.

Stain.

The Hero Killer stood before him, his blood-red eyes gleaming with a predatory intensity. His armor was battered but functional, his tattered scarf trailing behind him like a specter of death. His katana rested in his hand, the blade gleaming faintly in the dim light.

Mangetsu's throat tightened as he faced the infamous vigilante. He'd heard the stories, seen the aftermath of Stain's crusade. But nothing could have prepared him for the sheer weight of the man's presence.

"You don't deserve to call yourself a hero," Stain growled, his voice dripping with disdain. "You've traded your integrity for wealth, your purpose for comfort. You married into corruption, Bitsize. You became one of them."

A Battle of Words

Mangetsu's grip on his staff tightened, his jaw clenching. "You don't know anything about me."

Stain's lips twisted into a grim smile. "I know enough. You were once a man I respected—a hero who stood for justice. But now, you're just another pawn of the Yaoyorozu family. You've taken their blood money, built your life on their corruption. And for that, you must atone."

Mangetsu's chest heaved with anger, his eyes blazing with determination. "I didn't come here to argue philosophy with a murderer. I'm here for my daughter. Where is she?"

Stain's expression darkened, his grip on his katana tightening. "Your daughter... a child born of greed and sin. She's a victim of your choices, Mangetsu. But she's not here."

The words hit Mangetsu like a blow, his heart sinking. But he refused to give in to despair. He straightened, his resolve hardening. "Then I'll find her. And if you try to stop me, I'll make you regret it."

Stain's laughter echoed through the warehouse, cold and hollow. "Regret? That's a sentiment for the weak. Show me the strength of the hero you once were, Bitsize. Show me if you're worthy of redemption."

As the tension between them reached its breaking point, the two men moved simultaneously, their bodies blurring into action. The fight had begun.

The Duel in the Shadows

The tension in the warehouse snapped like a taut wire, and in an instant, Stain became a phantom, vanishing from Mangetsu's line of sight. Mangetsu's instincts screamed at him, and he shrank down to the size of a cricket just as Stain's katana sliced through the air where his neck had been. The blade hissed past, the force of its arc cutting through the silence like a scream.

Mangetsu reappeared on the ground a few feet away, his body springing to full size in an instant. His staff snapped out from his side, extending with a metallic clang, its gleaming edge catching the dim light. He crouched low, his stance balanced and ready, eyes locked on his opponent.

Stain stepped out of the darkness, his crimson eyes burning like embers. His katana gleamed, the blade dripping with malice. His movements were slow, deliberate—a predator savoring the hunt.

"You're fast, Bitsize," Stain said, his voice a guttural rasp. "But speed can't save a man from his sins."

Mangetsu's voice was sharp and steady. "You talk a lot about sins for someone who's left more bodies behind than some villains. Spare me the sermon."

Stain tilted his head, the faintest flicker of amusement crossing his face. "Coming from the man who once told me that everyone deserves saving, even the little guy? What happened to that hero, Mangetsu? The one who saved a stupid kid from himself all those years ago?"

Mangetsu's grip on his staff tightened, his teeth grinding. "I'm still that man. I've just learned that not every battle can be fought."

"Convenient," Stain sneered, taking a slow step forward. "Is that what you told yourself every time you turned a blind eye to the Yaoyorozu family's corruption? Every time you saw them destroy lives and looked the other way? You've become everything you once despised. A hypocrite. A coward."

The words struck like daggers, but Mangetsu refused to let them find purchase. He lunged forward, his staff whistling through the air as he swung it in a precise arc. Stain deflected with his katana, the two weapons colliding with a resonant clang that echoed through the cavernous warehouse.

A Battle of Masters

The fight exploded into motion. Mangetsu's movements were a blur, his body shrinking and expanding with dizzying speed as he weaved around Stain's relentless strikes. His staff struck out like a serpent, jabbing and sweeping with surgical precision, forcing Stain to stay on the defensive. But Stain was no ordinary opponent. His reflexes were razor-sharp, his katana moving with the fluidity of water as he parried and counterattacked.

At one moment, Mangetsu shrank mid-leap, evading a horizontal slash by a hair's breadth before reappearing above Stain, his staff coming down like a hammer. Stain sidestepped with inhuman agility, spinning on his heel to deliver a kick aimed at Mangetsu's ribs. Mangetsu twisted in midair, shrinking just enough to let the blow graze past him before retaliating with a sweeping strike to Stain's legs.

Stain stumbled, but only for a fraction of a second. His body twisted unnaturally as he slashed upward, forcing Mangetsu to roll away, his coat fluttering as he reoriented himself.

"You still fight like the hero you were," Stain said, his tone almost admiring. "But you've lost your soul. That's the difference between us."

"I haven't lost anything," Mangetsu growled, his voice laced with anger. He rushed forward, feinting a jab before pivoting into a sweeping kick aimed at Stain's side. The Hero Killer caught the movement, blocking with his forearm before driving the hilt of his katana toward Mangetsu's chest.

Mangetsu shrank, dodging the blow, and landed a solid strike to Stain's shoulder as he expanded back to full size. The force sent Stain staggering, but his grin only widened.

Clashing Ideals

"You know why I'm doing this, don't you?" Stain said, circling Mangetsu like a wolf. "It's not because I hate you. It's because I respected you. You taught me what it meant to be a hero. You said that a true hero fights for everyone—not just the people they love. So tell me, Mangetsu: what about the families suffering under the Yaoyorozu's tyranny? What about the daughters they've stolen, the lives they've ruined? Don't they deserve justice too?"

Mangetsu's jaw tightened, his chest heaving. "You don't know anything about what I've done—what I've tried to do. You think I don't care? You think I don't see the damage they've caused?"

"Then why haven't you stopped them?" Stain's voice rose, his anger palpable. "Why haven't you fought for the people you swore to protect? You only care now because it's your daughter. You're no hero, Mangetsu. You're just another man protecting his own while the rest of the world burns."

Mangetsu's response was a roar of fury. He charged, his staff spinning like a cyclone, driving Stain back with a flurry of relentless strikes. Stain blocked and dodged, his katana moving like a shield, but even he struggled to keep up with Mangetsu's onslaught.

The Final Gambit

The fight reached its peak as Mangetsu delivered a powerful strike that sent Stain's katana clattering to the ground. He lunged, his staff poised to deliver the finishing blow—but Stain was faster. In one fluid motion, he drew a hidden dagger and slashed upward, the blade catching Mangetsu's side.

Mangetsu stumbled, blood staining his coat, but he didn't fall. He gritted his teeth, his vision blurring as he steadied himself. Stain stood before him, his dagger dripping crimson.

"You're still strong," Stain admitted, his voice quieter now. "But strength alone doesn't make a hero. Conviction does. And yours died the moment you chose comfort over justice."

Mangetsu's voice was barely a whisper. "I... never stopped... trying."

Stain's expression softened, just for a moment. "Then prove it."

With a final, devastating strike, Stain drove his dagger into Mangetsu's chest. Mangetsu fell to his knees, his vision darkening as his blood pooled beneath him. But even in his final moments, he met Stain's gaze with unwavering resolve.

"You... were right," he rasped. "A hero... fights for everyone."

Stain knelt before him, his voice low. "You were my hero once, Mangetsu. Rest knowing I'll honor what you taught me."

As Mangetsu's body went still, the warehouse fell silent. Stain rose, his katana in hand, and disappeared into the shadows, leaving behind the man who had once inspired him to become something greater—and the tragedy of what he had become.

The Aftermath

The Aftermath

The Kodai household was silent, save for the low hum of the refrigerator and the rhythmic ticking of the clock on the wall. Dawn had barely broken when the phone call came. The shrill ring shattered the fragile quiet like glass, and Sakura Kodai answered with trembling hands.

Seconds later, the phone slipped from her grasp, clattering to the floor. She crumpled like a marionette with its strings cut, her knees hitting the hardwood with a sickening thud. A guttural sob tore through her throat, a sound so raw it seemed to hang in the air, reverberating through the home like a haunting echo.

Momo froze in the doorway, her breath catching as she clutched the frame. "Auntie?" she whispered, her voice trembling with fear. "What... what happened?"

Sakura couldn't answer. She pressed her hands against her face, as if trying to physically hold in the grief threatening to consume her. Tears streamed through her fingers, and her shoulders shook violently.

The atmosphere in the room grew suffocating. Momo's heart pounded in her chest as dread wrapped around her like icy chains. The sight of her once composed and powerful aunt broken before her made the pit in her stomach deepen. She stepped forward hesitantly.

"Aunt Sakura," Momo's voice was firmer now, though her own terror was evident. "What happened? Where's Uncle Mangetsu? Did he—did he find Yui?"

At the mention of Yui's name, Sakura let out a wail so anguished that it made Momo flinch. The older woman's trembling hands dropped from her face, and she finally looked at Momo with bloodshot eyes.

"He's gone, Momo," Sakura choked out, her voice fractured and barely audible. "Mangetsu… he's dead."

The words hit Momo like a freight train, the breath leaving her lungs in an instant. For a moment, the world seemed to tilt on its axis. The air turned heavy, the walls seemed to close in, and the sound of her aunt's sobs became muffled, as though she were underwater.

"No…" Momo whispered, her legs buckling as she stumbled back against the doorway for support. Her vision blurred, but she forced herself to remain upright, to process the weight of what she'd just heard. "That's… not possible. He… he promised he'd come back. He promised he'd find Yui!"

Sakura looked away, her hands trembling as she clutched her arms. "The police called," she said through gritted teeth. "They found his body in an alley near Musutafu… mutilated. They said it was the work of the Hero Killer. Stain."

The name alone sent a shiver down Momo's spine. Stain. The infamous Hero Killer whose twisted ideals had claimed the lives of countless heroes. Her uncle, Mangetsu Kodai, a man who had been her pillar of strength and warmth, was now just another victim of that monster.

Momo's legs finally gave out, and she sank to the floor, staring at nothing. Tears streamed down her face, but she made no sound. The weight of despair was too much to bear, too heavy for her heart to process.

For a long while, neither of them spoke. The silence between their broken sobs was deafening.

But as Momo sat there, her grief began to twist into something darker—something sharper. Her uncle's warm laughter, his encouragement during her training, his constant belief in her potential—all of it had been ripped away in an instant. And why? Because he had dared to stand up for what was right.

It wasn't fair.

It wasn't just.

Her hands clenched into fists so tight that her nails dug into her palms, drawing blood. She didn't care. The pain grounded her, gave her something to focus on amid the maelstrom of emotions threatening to drown her.

"I'll find him," Momo said, her voice quiet but laced with a steely determination that caught Sakura off guard.

Sakura's head snapped up, her tear-streaked face etched with panic. "Momo, no. Don't even think about it. Stain is—he's a killer. He'll—"

"Kill me like he killed Uncle Mangetsu?" Momo's voice cracked as she rose to her feet, her tear-stained face now set in a mask of resolve. "He didn't just kill my uncle, Aunt Sakura. He killed Yui's father. He took away one of the few people in this family who actually cared about doing the right thing."

Sakura tried to reach for her, but Momo took a step back. "I have to do something," she said, her voice trembling but resolute. "I can't just sit here and let his sacrifice mean nothing. If Uncle Mangetsu was brave enough to confront the darkness, then I will be too."

"You're not a hero yet, Momo," Sakura pleaded, her voice breaking. "You're just a student! If you go after Stain, you'll—"

"I'll die?" Momo interrupted, her tone laced with a bitter edge. "Then so be it. But I won't sit idly by while our family continues to fall apart. If we don't fight back, who will?"

Sakura had no answer, her tears flowing freely once more.

Momo turned on her heel and walked out of the room, her footsteps heavy with the weight of her grief and determination. She didn't know how she would find Stain or what she would do when she faced him.

But one thing was certain.

Mangetsu Kodai's death would not be in vain.

When Sakura received the visit from the authorities the next morning, she collapsed, her body wracked with sobs. But Momo, standing silently in the corner, saw the truth in her aunt's eyes.

This wasn't just grief. This was guilt.

Mangetsu Kodai, the good man who had married into the wrong family, had paid the ultimate price for their sins. And now, it was up to those he left behind to uncover the truth.

Section 1: The Funeral of Mangetsu Kodai

The sky was overcast, gray clouds swirling like the emotions of those gathered beneath them. The air carried a damp chill, as if the world itself mourned the loss of Mangetsu Kodai, the pro hero Bitsize. His funeral was a somber affair, held at a sprawling cemetery in Musutafu. Rows of black-clad mourners lined the area, their faces reflecting a collective grief. Heroes, civilians, friends, and family—all had come to pay their respects to the man who had been a beacon of strength and humility in a chaotic world.

Naomi Hayashi, Mistress Micro, stood near the back, her heart heavy as her eyes fixated on the ornate casket draped in a pristine white cloth. Her mentor, her guide, her friend—gone. It didn't seem real. The image of Mangetsu's smile haunted her, a stark contrast to the lifeless stillness now encased in wood and adorned with lilies.

Naomi's mind flickered with memories, moments of shared laughter and hard-fought victories. Her chest tightened. She felt like she had failed him, as if there was something more she could have done to prevent this.

Momo's Grief

Near the front stood Momo Yaoyorozu, her shoulders trembling as silent sobs wracked her body. Her mother, Yuna, held her close, whispering words of comfort that barely reached her ears. For Momo, Mangetsu wasn't just an uncle—he was a second father. Memories of his gentle encouragement during family dinners, his proud smile at her accomplishments, and his warm, hearty laugh filled her mind, making the loss unbearable.

Her father, Hisashi, stood beside them, his stoic expression masking the storm of emotions within. Though he rarely displayed vulnerability, even he couldn't deny the weight of Mangetsu's absence. His sharp gaze scanned the gathered crowd, lingering briefly on Sakura Kodai.

Sakura sat in her wheelchair, her face pale and drawn. Her hands gripped the armrests tightly, her knuckles white. Guilt and grief twisted her features. She hadn't just lost a husband—she'd lost the man who had been her anchor, the one person she'd truly loved in this world.