One Piece: I will become stronger by checking in

Kai watched as the CP0 captain withdrew a pitch-black pistol from his coat and aimed it directly at him. The moment the weapon was leveled, Kai felt an oppressive, primal fear grip him, his body halting instinctively.

His gaze locked onto the pistol, a cold seriousness washing over him. This isn't just some ordinary gun, Kai thought. The sheer aura radiating from it made his heart pound. Before he could react further, an overwhelming surge of energy erupted from the weapon, a concentrated wave of raw, destructive power.

Kai's eyes widened as the attack hurtled toward him. In a desperate counter, a shadow clone appeared at his side, while his signature move, Hakai, was unleashed. But unlike before, when Hakai had overwhelmed even Garp and his allies, it crumbled almost instantly under the force of the blast.

The energy storm surged forward, striking Kai with relentless fury. He swung his weapon in a last-ditch effort to block, but the sheer power sent him flying like a meteor. A guttural cry escaped him as he coughed up a mouthful of blood mid-air, his body wracked with pain.

Crashing into the icy battlefield below, Kai skidded to a halt amidst shards of shattered ice. His chest heaved as he struggled to rise, his ribs fractured and his vision blurred. Damn you, Im, he cursed under his breath, realizing the terrifying truth: the weapon had fired an attack imbued with pure, concentrated Conqueror's Haki.

There was only one person in history rumored to have wielded such mastery of Haki—Joy Boy. Yet now, Kai understood another held this power: Im. The knowledge burned at him, not out of fear, but frustration. Eight hundred years of power concentrated in a single attack... no wonder I'm in this state.

Even as pain coursed through his body, Kai's defiance burned bright. The Great Sage never backs down. He vowed silently to come back stronger, to face even Im when the time was right. But now was not that time.

Before he could gather himself, the CP0 captain approached with a dark, murderous intent. His face betrayed seething hatred, though some of it wasn't just directed at Kai—it was frustration at the situation, at the recklessness of the Celestial Dragon behind him.

The captain moved with calculated aggression, launching toward Kai. But despite his injuries, Kai grinned. This fool has no idea who he's dealing with.

In an instant, Kai's weapon appeared in his hand, and with a powerful swing, he intercepted the captain's attack. The collision echoed through the battlefield, but Kai winced—his earlier injuries had taken their toll. For the first time, he felt himself pushed to the edge.

Before he could regroup, reinforcements arrived. Aokiji, Garp, and Kuma charged forward. The odds, already unfavorable, turned grim. With the trio's combined strength bearing down on him, even Kai, the unrelenting force of nature, found himself outmatched. Blow after blow rained down, his movements slowing, his stamina dwindling.

Finally, Garp found an opening. His fist, carrying the weight of decades of battle-hardened strength, slammed into Kai's side. The impact sent him flying, smashing into the ground with such force that the ice cracked and buckled beneath him.

The trio stood above the crater, catching their breath as they looked down at their opponent. Though victorious, there was a glimmer of respect in their eyes. If it weren't for that weapon, they wouldn't have been able to subdue him, they silently admitted.

Kai, bloodied but unbroken, pushed himself up once more. A sharp cough escaped him, a fresh stain of crimson marking the ice beneath. Retreat now, fight later, he told himself. He had bought Robin and the others enough time to escape—his mission was complete. But before retreating, there was one last thing he had to take care of.

His gaze snapped to a certain direction, and his figure blurred as he vanished.

Charlos stood arrogantly, mucus dribbling down his face as he laughed in grotesque delight. "Hahaha! That filthy commoner finally learned his place. This is the fate of anyone who dares to challenge the noble Celestial Dragons!"

He sneered, basking in his perceived victory. "When they bring him to me, I'll make him kneel and serve as my slave! Hahaha—"

"Really? I'm curious," a cold voice interrupted from behind. "How exactly do you plan to make me your slave?"

Charlos froze. His blood turned to ice as a shadow loomed over him, and sweat drenched his back. Slowly, trembling, he turned to face Kai, who stood there, bloodied but radiating raw, unrelenting fury.

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I have no clue where that came from. I don't think a weapon can hold on to that much haki. Plots strikes boys.