A full month passed since Dragon had begun teaching them the foundations of Haki. During that time, Jack's progress was nothing short of monstrous. What had started as clumsy attempts at hardening his fists eventually became precise control. By now, he could freely coat his arms in a dark sheen of Armament Haki, his strikes carrying a weight that made even Dragon acknowledge him.
But Jack wasn't satisfied. He had set his sights on something higher.
On this day, he stood opposite Dragon, sword in hand, sweat glistening on his young but hardened frame. He tightened his grip and focused, trying to extend the flow of Haki beyond his body and into the steel. His blade flickered with a faint shadowy hue—unstable, incomplete. Still, he swung.
Dragon blocked with a single punch coated in Haki, the clash sending sparks flying. The unstable coating cracked, and Jack's heart skipped a beat. His sword, after all, wasn't just any sword—it was a Supreme Grade blade, a treasure forged to withstand the harshest of battles. But even such weapons could be worn down without proper mastery of Haki.
Gritting his teeth, Jack tried again. This time he poured everything into the flow, feeling the energy crawl from his arm into the blade. With a sharp swing, the weapon's steel turned jet-black, glimmering under the sunlight like an obsidian fang. Dragon's eyes widened slightly, impressed. Their next clash rang like thunder, Jack's newly coated blade holding firm against Dragon's punch.
A grin spread across Jack's face. So this is it. The path to a Black Blade… just like Ryuma, just like Mihawk. He pressed forward, strike after strike, growing sharper, smoother, more confident with each swing. Dragon parried calmly, yet inwardly acknowledged the boy's astonishing growth rate.
Meanwhile, a short distance away, Aramaki was locked in his own trial. Dragon had ordered him to abandon his Devil Fruit for training—no roots, no branches, no tricks. Just fists, flesh, and willpower. His task was brutally simple: to strike stone with his bare hands until the wall before him yielded.
The ground around him was already speckled with flecks of blood. His knuckles were raw and swollen, wrapped in bandages that had long since turned crimson. Every punch sent fresh jolts of pain racing up his arms, yet he forced himself to continue, gritting his teeth so hard his jaw trembled.
He risked a glance toward Jack, who was trading blows with Dragon like an equal. His chest tightened.
'How can he make it look so easy?' Aramaki thought when he remember the scene where Jack is just punching the huge boulder that he was training on, and with Jack's hand also covered in blood.
Jack's swings were fluid, his blade already drinking deeply of Haki's power. In contrast, every one of Aramaki's strikes felt clumsy and hollow, his spirit not yet aligning with his body. He clenched his fists tighter, ignoring the sting, and raised them again.
"Again," he whispered to himself, voice hoarse. His arm trembled, then slammed into the stone. Blood sprayed, the impact echoing like a drumbeat. He staggered, nearly collapsing, but caught himself on shaking knees.
"Again!"
Though agony consumed him, the fire in his eyes burned brighter.
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Back on the training field, the clash between Dragon and Jack had reached a fever pitch. The boy's growth over the past weeks was staggering, and Dragon could feel the intensity behind each swing mounting higher and higher. What began as a test of Haki was now a storm of raw strength and sharpened willpower.
Jack's eyes gleamed with focus as he tightened his grip on his sword. He stepped in with a fluid motion and unleashed a strike unlike the others—his blade arced down with such explosive force that it didn't feel like steel cutting through the air, but like a cannon erupting at point-blank range.
The impact was devastating. The ground beneath them quaked violently, cracks spiderwebbing outward in every direction. Within moments, the earth collapsed, forming a massive sinkhole that swallowed both combatants in a cloud of dust and shattered stone.
Dragon landed lightly, bracing himself as the tremors subsided, but his expression was far from calm. His usually steady gaze widened in shock, his breath caught in his chest. That strike—its pressure, its rhythm, its sheer destructive presence—it was all too familiar.
"How did you know this swordsmanship?" Dragon's voice carried a rare edge of alarm.
Memories surged unbidden to the surface. God Valley. The chaos, the screams, the monstrous figures who had gathered there. Among them stood Rocks D. Xebec, a man whose ambition and violence had left scars on history itself. Dragon had seen it with his own eyes back then—Xebec's sword tearing through the battlefield with a style so brutal and overwhelming it felt like the world itself bent under the weight of his strikes.
And now, before him, an eight-year-old boy had just mirrored that same nightmare.
Jack blinked in confusion, lowering his blade slightly. "I created it myself," he said simply, his tone honest, almost innocent. There was no hint of deception, no sign he even understood the weight of what Dragon was asking.
For a moment, Dragon studied him in silence, his mind torn between disbelief and calculation. 'Impossible. That technique should have died with Rocks. Could it be coincidence? Or… fate?'
The wind blew across the ruined earth, carrying silence between the two. Dragon finally straightened, masking his turmoil behind a controlled expression, though his fists remained clenched.
Jack tilted his head, confused by Dragon's sudden intensity. "Why? Did it remind you of something?" he asked, his grin returning as if the world hadn't just cracked beneath his feet.
Dragon didn't answer immediately. Instead, he narrowed his eyes. "You truly created it yourself?"
"Yes," Jack replied without hesitation. "It's mine. strikes that explode like cannons. I thought it fit me."
Dragon's lips tightened into a thin line. His instincts screamed that there was more to it than mere chance. Whether Jack realized it or not, he was treading a path carved by one of the most dangerous men to ever live.
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Later that evening, after the dust of their sparring had settled, the three of them sat down to share another hearty meal. The fire crackled, casting long shadows across their improvised camp, while the aroma of roasted sea king meat drifted through the night air. As they ate, Dragon's mind returned again and again to the devastating strike he had witnessed earlier. Finally, he broke the silence.
"Jack," Dragon began, his tone calm but edged with curiosity, "that sword technique you used today… can you explain the concept behind it? What drives its power?"
Jack paused mid-bite, then set his food aside with a grin. "Sure. You've taught us plenty about Haki. Consider this my way of paying you back."
Aramaki, half-distracted by his food, perked up at that. "So you're finally going to explain that cannon-like slash of yours, huh? I was wondering how you made the ground collapse like that."
Jack nodded, then stood and drew his sword. He began demonstrating the technique slowly, his movements deliberate. He explained how it wasn't just about raw strength, but about compressing force into the edge and then releasing it explosively—like a spring snapping or a cannon firing at the moment of contact.
Dragon leaned forward, his sharp eyes following every detail. Unlike Aramaki, who gawked with open admiration, Dragon's expression was unreadable, analyzing each swing with the same intensity he applied to Haki.
Jack repeated the motion again and again, adjusting his rhythm each time as he answered Dragon's precise questions. Where did the power concentrate? How did the stance channel the weight? How much of it relied on instinct versus deliberate control? Jack, eager to share, explained everything he had discovered through trial and error.
Finally, Dragon rose to his feet. "Interesting… very interesting."
He mimicked the strike, but without a sword—his hands slicing through the air with controlled precision. At first, the motion lacked the raw weight of Jack's impact, but slowly, Dragon began weaving the principle into his own martial arts. Each punch, each palm strike, now carried a hint of that same explosive release.
Jack's eyes widened in excitement. "You're already getting it! If you mix that with your Haki, it'll be even scarier."
Aramaki chuckled. "Great. As if he wasn't terrifying enough already."
From that day onward, the new style became a part of their routine. Every training session, Jack would spend at least an hour teaching Dragon the intricacies of his so-called "impact swordsmanship." In return, Dragon offered insights Jack hadn't considered—ways to refine the stance, conserve energy, and integrate Haki into each strike.
The result was something none of them expected: their lessons began flowing both ways. Jack was no longer just Dragon's student; in his own way, he had become Dragon's teacher too.