The Cell Games had ended in devastation. Goku had sacrificed himself to save Earth, and though the planet had been spared, the cost was felt deeply by those who loved him. Among them was his twin sister, Y/N. The bond between twins is a unique one, and Y/N's grief was profound. As the days turned into weeks and weeks into months, her sorrow festered into a dark determination.

Years later, as the World Martial Arts Tournament approached, a new, sinister power began to rise. Babidi, seeking to harness the strongest warriors, turned his gaze towards Earth looking to revive Majin Buu.

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Y/N staggered, clutching her head in anguish, desperately trying to resist the encroaching darkness. Gohan and Goku rushed to her side, their worry palpable. 

"Y/N, hang on!" Gohan pleaded, his voice tinged with fear. "Babidi's magic..." he muttered, his voice filled with worry as he watched Y/N struggle against the insidious influence.

Y/N's eyes flashed with a brief moment of clarity, a silent plea for help directed towards Goku. She knew what was happening - the ancient wizard was attempting to seize control of her mind, twisting her thoughts and desires to his will. 

Desperation etched her face as she fought against the dark force invading her being.Babidi's malicious laughter echoed through the chamber as he tightened his grip on Y/N's psyche. With a triumphant sneer, he spoke an incantation, and a sinister symbol materialized on Y/N's forehead, marking her as his puppet.

"No! Y/N!" Goku shouted, his fists clenched in frustration. 

Vegeta, was stunned as he felt the sudden spike in her power. Goku stepped forward, his heart heavy with concern. "Y/N?"

Her response was a scream of fury, her energy exploding around her.

Y/N's eyes flashed with sinister defiance as she turned to face Goku, her expression challenging. "I challenge you, Goku," she declared, her voice echoing with a mixture of determination and sorrow.

Goku's brow furrowed in concern and confusion. "Y/N, what are you doing? This isn't you!" he exclaimed, his voice tinged with desperation.

Supreme Kai attempted to intervene, his expression grave. "This is madness! Y/N, you must resist Babidi's influence!" he urged, his voice filled with authority.

But Y/N remained steadfast, her gaze locked onto Goku's. "I won't let you hold back, Goku." she stated, her voice trembling with unshed tears.

Goku hesitated, torn between his love for his sister and the need to protect everyone from the destructive power she now wielded.

Gohan and Supreme Kai watched with growing concern, their hearts heavy with the weight of what was at stake. "We have to do something," Gohan murmured, his voice filled with determination.

Supreme Kai nodded solemnly. "We cannot allow this battle to happen. The fate of the universe hangs in the balance," he stated firmly, his eyes blazing with resolve.

But Y/N, consumed by her anger and the overwhelming power coursing through her veins, refused to back down. "Stay out of this! This is between me and Goku," she snapped, her words sharp with anger and pain.

Goku's resolve hardened. "Move aside, Gohan, Supreme Kai. I have to do this," he declared, his voice brooking no argument.

With a nod to Gohan and the others, Goku followed y/n and Babidi, determination etched in every line of his face.

As they arrived in the arena, Goku, his heart heavy with the weight of their shared history and the current conflict, met Y/N's gaze with equal parts determination and sorrow. "Y/N, I don't want to fight you. Please, don't make me do this," he implored, his voice trembling with emotion.

But Y/N's mind was set. With a fierce battle cry, she launched herself at Goku, her attacks fueled by a potent mix of anger, fear, and the lingering remnants of Babidi's influence.

The arena shook with the force of their clash, each blow resonating with the weight of their shared history and familial bond. Goku fought defensively, his heart heavy with the knowledge that he was battling not just an opponent, but his own beloved sister.

"Why won't you listen, Y/N?" Goku shouted, frustration evident in his voice as he blocked her relentless assaults.

Y/N gritted her teeth, her eyes flashing with unbridled fury. "Because you left us!" she retorted bitterly, each word laced with pain. "You sacrificed yourself, and I needed you!"

Goku's heart clenched at her words, guilt washing over him like a tidal wave. "I... I didn't mean to leave you," he admitted, his voice choked with emotion. "I thought it was the only way..."

Y/N's attacks faltered for a moment, her expression wavering as his words struck a chord within her.

Goku's heart broke as he watched his sister struggle with the darkness consuming her. "I'm here now, Y/N. Please, let me help you," he implored, reaching out to her with trembling hands.

But Babidi's influence was too strong. With a sinister laugh, the wizard intensified his control over Y/N, pushing her beyond her limits.

"No..." Goku murmured, his voice filled with despair as he faced the reality of what had become of his sister.

Supreme Kai, sensing the impending catastrophe, moved to intervene once more. "Goku, we must stop her before it's too late!" he urged, his voice urgent.

With a heavy heart, Goku nodded, steeling himself for the battle ahead. "I won't let you down, Y/N," he whispered, his voice barely audible over the rising tumult.

Y/N's newfound power surged, shaking the very ground beneath them. With a primal scream, she unleashed a devastating blast that tore through the arena, leaving Goku momentarily stunned and vulnerable.

Goku's heart sank as he watched Y/N, his beloved sister, succumb to the darkness. "Y/N, please..." he whispered, his voice choked with emotion.

But she was too far gone, her grief twisted into something unrecognizable. In a final, desperate move, she unleashed a devastating attack, knocking Goku unconscious. The arena trembled under the force of her power, and in a moment of sheer destruction, she obliterated it.

As the dust settled, Y/N stood amidst the rubble, her breath ragged. 

She looked around, the weight of her actions crashing down on her. 

She saw nothing around her, and in the distance Gohan's lifeless form, and crumpled to her knees, the realization hitting her like a tidal wave. "What have I done?"

Y/N stood amidst the destruction, her heart heavy with guilt and regret. She had unleashed chaos upon her loved ones, driven by forces beyond her control. Tears streaked down her face as she realized the enormity of her actions.

And then, from the depths of the earth, a creature stirred—a being of pure malevolence and limitless power. Majin Buu had awakened, drawn by the chaotic energies unleashed by Y/N's transformation.

Y/N's eyes widened in horror as Majin Buu descended upon her, his monstrous form casting a shadow over her fragile figure. She knew she had to make amends, even if it cost her everything.

With a steely resolve born of desperation and sorrow, Y/N faced Majin Buu in battle. Her attacks were fierce, fueled by guilt over Gohan's supposed death and a desire to protect her brother, Goku. But Majin Buu proved relentless, his laughter echoing cruelly in the chaos.

In a moment of clarity, Y/N realized there was only one way to stop Majin Buu's rampage—to sacrifice herself.

And then, in a blinding flash of light, Y/N unleashed her final gambit. With a selfless roar, she poured every ounce of her remaining energy into a devastating attack, hoping against hope that it would be enough to vanquish Majin Buu.

For a fleeting moment, all was still.

And then, silence.

Goku woke with a start, his heart pounding in his chest. He looked around, his eyes searching desperately for any sign of his sister, but all he saw was a massive crater near where he last saw her.

"Y/N!" 

Tears streamed down his face as Goku knelt beside the crater, his grief and rage intertwining. 

He slammed his fists against the ground in anger over and over, "I should have done more! I could've prevented this!!"

His strength sent the ground flying, creating a small crater around himself. 

"I'm sorry, Y/N," he whispered hoarsely, his voice cracking with emotion. "I'm so sorry..."

Vegeta who had watched the scene unfold approached him, his expression solemn, normally aloof, he gripped Goku's shoulder with surprising gentleness.

 His voice was low but held respect. "Kakarot, this isn't over. Y/N's sacrifice can't be in vain. We have to stop Buu now."

Goku nodded slowly, his fists clenching as he struggled to contain the turmoil within him. "She deserved better," he murmured, his voice barely above a whisper. "I should've been there for her."

Vegeta's jaw tightened, his own emotions raw and unguarded. "We both failed her," he admitted gruffly, his pride momentarily set aside in the face of their shared loss. "But we can't let her sacrifice be in vain. We have to defeat Buu."

With a solemn nod, Goku rose to his feet, his resolve hardening once more. "You're right, Vegeta," he said firmly, his gaze turning towards the looming threat of Majin Buu. "We'll finish this. For Y/N. For everyone she tried to protect."

a/n- crimsonshadow487 I kind of struggled to try to find when to start writing from, but I hope you like it and it was what you were wanting :)