Though he had half expected it, Koushirou's Shimotsuki: Nine Dragons Flash still failed to leave the slightest mark on Don.
Don, meanwhile, glanced at his halved HP and sighed inwardly. His master had clearly been holding back.
Those countless slashes, each wrapped in Armament Haki and cutting from all directions—that was no ordinary sword technique.
And yet, Don had already realized the truth.
Koushirou was no longer his match.
Because he had not even revealed the true might of the Flame-Flame Fruit.
Observation Haki paired with a Logia ability—against any opponent, that was an utterly terrifying combination.
Fwooh
Don exhaled deeply. The flames sheathing his sword slowly receded until none remained.
It might seem foolish not to use his greatest strength, but Don had come to Koushirou for precisely this reason: to prove he could become strong without relying on the Flame-Flame Fruit.
Though the fruit's weakness had been erased thanks to his system's digitization, its overwhelming destructive power was still an easy crutch.
"Haki is everything."
Extreme words, perhaps, but not wrong.
To stand among the world's strongest, powerful Haki was indispensable.
And so Don suppressed his Devil Fruit's power entirely.
Koushirou narrowed his eyes, immediately growing wary.
That last exchange had consumed a vast amount of stamina and Haki. If not for the repeated sparring over the past year—and the recovery of his body over that same time—he might not have endured it at all.
Now, seeing Don's expression and movements, Koushirou sensed what was coming.
Fwoosh!
Don's figure blurred, closing the distance in an instant. His body moved on instinct, sword cleaving toward Koushirou.
With just that single strike, Koushirou, a top-class swordsman, understood Don's intent. He met the blow head-on.
Their figures flickered across the beach. Slashes laced with Haki burst outward, carving scars in every direction.
Steel clashed, sparks flaring with each collision.
In pure swordsmanship, Don could not compare.
One could hardly expect a man who had trained barely a year—who had only recently found his own path—to defeat a swordsman who had honed his craft for decades.
But Don possessed far greater physical strength. His reserves of Haki were deeper.
His monstrous physique placed him on a tier Koushirou could not match.
With an offense that ignored defense entirely, Don pressed forward relentlessly, leaving Koushirou briefly flustered.
"This brat… abandoning defense altogether, relying on the fact that his body won't be injured?"
Koushirou was speechless.
Don truly hadn't absorbed his teachings. Koushirou had never once instructed such reckless swordsmanship.
And yet—this style suited Don perfectly.
Don himself, however, kept his eyes fixed on his HP.
This battle could have ended already.
After all, unlike him, Koushirou had no digitized body. A single serious wound to a vital point would mean grievous injury—or even death.
After nearly a year together as sparring partners, Don would not allow such an outcome.
What he wanted was something else entirely.
To deliberately reduce his HP—until it triggered the condition he sought.
Because soon, he would leave this place. He needed to know, with certainty, what power lay dormant in him once Unyielding activated.
So that, in the future, when he faced truly fearsome enemies, he would be prepared.
Unaware of Don's intentions, Koushirou continued pressing him, believing his disciple unaffected by the storm of strikes. In truth, he was unwittingly helping Don lower his HP.
10%!
5%!
1%!
[Your HP has dropped to minimum. Unyielding has been activated.]
Suddenly, a message flashed before Don's eyes.
Instinctively, he lifted his left hand. The incoming Wado Ichimonji—he caught it between just his thumb and forefinger.
An overwhelming surge of Haki erupted from within him, bursting uncontrollably into the air. It roared around him like a cloak of living flame, blazing and wild.
The sheer pressure bore down on everything nearby.
Koushirou froze, wide-eyed, as Don's aura transformed before him.
Within the keen senses of his Observation Haki, his disciple now resembled a monster—an abomination radiating crushing terror. Cold sweat streamed down his back.
Don, in turn, clearly perceived the change in his master's emotions.
He could feel it.
Fear.
"It's over!"
Don released the blade from between his fingers and spoke calmly.
"You…!"
Koushirou's voice shook. The suffocating pressure left him barely able to breathe, let alone speak.
"My trump card!"
Don declared. In the next instant, his surging Haki withdrew, and the oppressive aura dissipated as though it had never been.
Koushirou exhaled sharply, relief and confusion warring in his gaze.
He could not understand what had just happened to Don.
"Sunset Prison Garb."
Don whispered. The words startled Koushirou, but before he could react, a scorching gust hurled him backward.
Centered on Don, flames erupted skyward, engulfing half the island. Within the inferno, Don stood cloaked in a fiery mantle, as though wearing a coat woven from living fire.
The air itself warped beneath the heat.
"Torch!"
Boom!
A colossal firestorm rose, a tornado of flame that swallowed half the island in an instant.
"City-Burning Hand!"
Above the sea, a titanic hand of fire—larger than the island itself—clapped shut. The searing heat boiled the ocean, shrouding the world in thick fog.
Winds from the blazing vortex swept the fog away, only for it to gather and dissipate again in endless cycle.
"What… what is this?"
Koushirou stumbled back step after step, retreating to the safety of his boat. Staring at the sea of flames consuming both island and ocean, his eyes brimmed with shock.
"Ashes of Heaven and Earth!"
A voice thundered in his ears. Then he saw it.
A single, terrifying slash split the island in half. Though he could not even glimpse its full form, he saw the sea itself cleaved open.
The ocean could not mend the wound. Water boiled away faster than it could rush back in.
The sword scar widened endlessly.
Until at last, the flames receded. The sea surged back, filling the rift, sending waves crashing violently against Koushirou's ship.
But Koushirou barely noticed. His gaze was locked on the island's heart.
At its charred, hollowed center stood Don—calm, unmoving.
And in his hand, the blade.
Through Observation Haki, Koushirou felt a dread unlike any he had ever known emanating from that sword.
But Don had not unleashed the strike.
The monstrous aura faded as quickly as it had come.
Don leapt lightly back onto the boat.
Koushirou opened his mouth, but no words came.
"What a shame," Don murmured. "The Rising Sun Slash didn't come out. I could feel it—if I had released that strike, Flame wouldn't have endured. To unleash it, the sword must truly become a Black Blade."
Koushirou was silent for a long moment, then finally asked:
"And if you had unleashed it?"
"That?" Don turned his gaze toward the island, now ravaged beyond recognition by fire. "The island might well have been destroyed."