Naruto: The Avenger of the Uzumaki clan

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"But—!"

Karin's protest was cut short as Menma raised a hand, his sharp gaze silencing her.

"Enough, Karin. Power up the instruments," he said, his tone calm but resolute. "If this fails, we'll still have data to refine the next attempt."

The quiet authority in his voice left no room for argument.

Taking a deep breath to steady herself, Karin turned to the console and began activating the equipment. The sterile lab filled with the low hum of machinery coming to life. Meanwhile, Menma removed his shirt, revealing a body hardened by years of grueling training. His bronze skin bore faint scars—reminders of battles fought and lessons learned.

Without hesitation, he laid himself on the cold, metallic surface of the experimental table. One by one, he attached the monitoring wires to his body, his movements steady despite the weight of the moment.

"Menma..." Karin's voice wavered, her hands trembling as she prepared the final steps.

"This has to work, Karin," Menma replied without looking at her. His hand reached for the syringe filled with a glowing blue-green liquid. For a moment, he hesitated, his expression unreadable. Then, meeting Karin's worried gaze, he offered a faint smirk.

"I'll endure it. I always do."

With those words, he plunged the needle into his arm, pushing the serum deep into his bloodstream.

"!?"

The reaction was immediate. Menma's body arched violently as a wave of ice shot through his veins, followed by an unbearable heat that seemed to ignite every cell in his body. His breathing turned ragged, and his muscles spasmed uncontrollably.

'This... is far worse than before!'

The searing pain tore through him, threatening to overwhelm his resolve. His mind flashed back to Tsunade's Creation Rebirth—a technique that forced cells to regenerate rapidly, sacrificing lifespan for power. This serum felt like that, but magnified a hundredfold.

His fingers dug into the table, and his jaw clenched tightly to stifle another scream.

"I won't... break," he hissed through gritted teeth.

Karin's eyes darted between Menma and the monitors. The data was staggering. His cell division rate had skyrocketed, far surpassing any previous trials. They were approaching the critical threshold—the point of no return.

"Stay with me, Menma," she whispered, her voice almost a prayer. "Please don't—"

"AHHHH!"

Menma's scream echoed through the lab, his body convulsing violently. Karin flinched but stayed glued to the console, her hands flying over the controls to record every spike and anomaly.

The numbers climbed dangerously close to the critical limit, and Karin's heart pounded in her chest.

'If it goes any higher, his body won't hold together.'

Minutes dragged by, each second an eternity. Then, just as the numbers seemed poised to break past the threshold, they began to stabilize. The rapid ascent slowed, then plateaued, settling just below the critical point.

Karin let out a shaky breath, sagging against the console in relief.

"Menma?" she called softly, rushing to his side once the alarms silenced. His body lay still, drenched in sweat, his chest rising and falling in uneven breaths.

He opened his eyes, a weak but determined smile playing on his lips. "Hurts like hell... but I'm still here. Did we get the data?"

"Yes." Karin's voice was steadier now, though her hands still trembled as she wiped his forehead with a cloth. "The cell division rate exceeded our predictions, but... everything else stayed within acceptable limits. How do you feel? Any changes?"

Menma closed his eyes for a moment, focusing inward.

"Strength is... building," he said slowly, his voice rough. "Like every cell in my body is adapting, becoming stronger. My chakra—" He paused, his hand glowing faintly with a controlled surge of energy. "It's more responsive. Denser."

Karin's eyes widened, her scientific curiosity momentarily overtaking her concern. "You mean your chakra network has already expanded? That's incredible, Menma! This could—"

"It's not enough," Menma interrupted, his tone sharper now. He slowly sat up, wincing but resolute. "I'll need more trials. This power… it has to be perfect before I face them."

Karin frowned, but she nodded, understanding his unyielding resolve.

"Just promise me," she said quietly, "you won't push past your limit next time. If you die, all of this will mean nothing."

Menma chuckled weakly, the sound tinged with grim determination. "I'm not dying yet, Karin. I've got too much left to do."

As Karin moved to record the last of the data, Menma clenched his fists, feeling the faint flicker of power coursing through him.

'This is only the beginning. I'll surpass them all. No matter the cost.'

She watched him intently, her gaze filled with anticipation. The goal of the experiment was ambitious: push Menma's physical and chakra limits to the brink, perhaps even awaken new abilities. But body modification experiments were always a gamble—there were no guarantees, only risks.

Menma flexed his fingers, his body still pulsing with the lingering tension from the serum. The changes within him were subtle but undeniable, like an unfamiliar hum coursing through his very cells.

"Honestly... I don't feel much of a difference yet," he said finally, his tone measured.

Karin frowned, but her scientific curiosity kept her hope alive. "These things take time to manifest. We'll need to monitor you over the next few days, run more tests. The effects might not be instantaneous."

Menma chuckled softly, wincing slightly as the pain still lingered. "Time, huh? At least we didn't blow past the critical threshold this time."

Karin allowed herself a small smile. "Yeah, but let's not tempt fate. The margin was way too close. We need to monitor you carefully, Menma. No cutting corners."

Sitting up on the cold steel table, Menma grimaced as the serum's aftereffects weighed on him like lead. "We'll keep tracking progress," he agreed. His gaze turned sharp, almost predatory. "If this works, we'll be one step closer to reaching the Otsutsuki clan's level. If I can achieve that, a shortened lifespan will mean nothing. They've already surpassed the limits of mortality. So will I."

Karin's eyes widened at his words, but she didn't argue. Menma's goals had always been far beyond the grasp of the ordinary shinobi.

Flexing his hands again, Menma frowned thoughtfully. "The cellular activation—it's subtle. Adaptability like this isn't something you notice outright. It's an invisible improvement. But..."

He closed his eyes, focusing inward, tracing the new patterns of energy coursing through him. A faint hum of vitality reverberated, stronger than before, yet still incomplete.

'If it weren't for my Uzumaki bloodline, I probably wouldn't even sense this.'

Boom!

Suddenly, Menma's chakra exploded outward, a blazing aura that rippled like fire. His body instinctively called upon Kurama's power, and within moments, he reached the Four-Tails state. The air thickened with raw energy as the chakra tails flicked upward, crackling with power.

Normally, such a transformation brought chaos. When Naruto accessed this level during his battle with Orochimaru, it was barely controlled—a storm of destruction fueled by rage. But Menma was no stranger to the Nine-Tails' chakra. Unlike Naruto's early struggles, Menma had forged a pact with Kurama, ensuring the beast's consciousness wouldn't interfere.

Karin shielded her face from the pressure, her heart pounding as she studied the output on the monitors. "Menma! Are you stable?"

"I'm fine," he replied tersely, his voice calm but strained. Unlike other Jinchuriki, Menma had honed his control over Kurama's power. He didn't need a chaotic half-transformation like Killer B or Yagura. His strength came from balance—mastery over his chakra network, combined with techniques like the Adamantine Sealing Chains.

But even with this mastery, Kurama's chakra remained a volatile force. The Eight Trigrams Seal still restricted the full flow of power, a barrier that had yet to be undone.

Menma opened his eyes, the crimson glow of the Tailed Beast's chakra receding slightly. His voice carried a hint of frustration. "There's a slight improvement... but nowhere near enough. All this pain, and I'm still far from where I need to be."

Karin's heart sank at his words. She clenched her fists, guilt and worry swirling inside her. "Does this mean... all the effort was for nothing?"

Menma's expression softened as he noticed her distress. He shook his head, offering a faint smile. "It's not wasted, Karin. Progress is progress, no matter how small. We'll need more trials, more data. This is only the beginning."

"But what if—" Karin's voice caught, trembling with emotion. "What if we push too far? If Kurama's chakra spirals out of control, you—"

Menma reached out, resting a hand on her shoulder. "That's why we're doing this. To make sure that never happens." His voice was firm, resolute. "Kurama won't go berserk. He trusts me, and I trust him. But the seal—" His gaze darkened. "The seal's restrictions are holding me back. If we want real results, we'll need to weaken the Seal gradually."

Karin hesitated, biting her lip. "You mean dismantling part of the Eight Trigrams Seal? Menma, that's dangerous. If it fails—"

"It won't fail," Menma interrupted. His voice carried a weight that left no room for argument. "Every step we've taken has been calculated. Once the seal is fully dismantled, I'll finally be able to use Kurama's power without limits. Only then will I be ready."

Karin's stomach churned at the thought, but she knew Menma wouldn't be swayed. His determination was unyielding.

"You're thinking about them again, aren't you?" she asked quietly.

Menma's expression hardened. "Akatsuki. Nagato. Madara. They're coming for us, Karin. And I won't let them take anything from me."

Karin swallowed hard, the weight of his words settling over her. She could see the fire in his eyes—the drive that had carried him through countless battles, and the burden of a destiny only he could bear.

"I understand," she said softly. "But promise me one thing, Menma. Don't push yourself to the point of no return. You can't protect anyone if you destroy yourself first."

Menma's gaze softened slightly. He patted her head, a rare gesture of reassurance. "I'll be fine. Trust me, Karin. We'll finish this together."

As Karin nodded reluctantly and returned to her console, Menma closed his eyes, feeling the faint hum of Kurama's chakra settle within him.

'This is only the beginning. No matter how long it takes... I'll surpass them all.'

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