The hammer rebounded high from the impact, the shock forcing Rayleigh back half a step.
Bullet's right arm, covered in scales, did not even have a scratch.
"Fifty percent strength."
The second swing came down.
The sound was louder, the shockwave strong enough to whip Bullet's hair back, but his arm still did not budge. Instead, a dent appeared on the hammer's head itself.
"Seventy percent."
This time, Rayleigh wrapped Armament Haki around the hammer.
A dark sheen coated the metal. The power behind this strike was enough to smash through a battleship.
Boom.
The collision shook the entire lower deck.
Support beams groaned under the strain, tools on the walls clattered down in a noisy cascade.
The wooden floorboards under Bullet's feet exploded, both his legs sinking three inches into the planks.
But his right arm was still intact.
Only the dark gold shimmer on the scales flickered violently for a few seconds, dispersing the impact evenly along the entire arm.
Rayleigh lowered the hammer and stared for a full ten seconds at the clearly deformed hammerhead.
"You..."
He finally spoke, disbelief in his tone.
"How did you even think of that?"
Bullet let the Black Scale Armament fade.
The dragon scales receded, his arm returning to human form. He flexed his fingers and answered,
"I did not think of it. I felt it."
"In the gravity field, I noticed I kept unconsciously guiding my Haki into the scales. It was like my body's instinct."
He lifted his arm.
The dark gold lines under his skin were especially clear in that moment.
"Nidhogg's inheritance must have fragments of memory about this kind of power."
"I just... pieced them together."
Rayleigh exhaled slowly, then suddenly burst into laughter.
"Ha ha ha ha! Good. This is great!"
He slapped Bullet's shoulder hard.
"Kid, do you know what this means?"
Bullet thought for a moment.
"It means my defensive system is finally taking shape?"
"No."
Rayleigh shook his head, eyes shining with excitement.
"It means you have already found the path that belongs only to you."
"Most ability users try to make their Devil Fruit work alongside Haki."
"But you did the opposite."
"You used Haki as the skeleton, your fruit as the flesh, and built an entirely new combat system."
"This Black Scale Armament of yours is not just stacking defenses. It is a complete qualitative change."
"Its defensive efficiency, its energy usage, all of it far surpasses standard Armament coating."
"And more importantly..."
He paused, looking Bullet straight in the eye.
"This is only the beginning."
"If one day you can put your entire body into this state... in the New World, there will not be more than five people who can break through your defense."
Bullet clenched his fist, feeling the energy still flowing beneath his skin.
Five people, huh?
Not enough.
He wanted a defense no one could break.
"What next?"
He asked.
"Two things."
Rayleigh raised two fingers.
"First, spread the Black Scale Armament across your whole body."
"Start with the torso, then your legs, and only at the end your head."
"This will take time, but you have already grasped the core principle. The rest is repetition and polish."
"And the second?"
"Testing offense."
A sharp glint crossed Rayleigh's eyes.
"A massive defense upgrade is just the start."
"If you can apply the properties of Black Scale Armament to your attacks... for example, your dragon claws..."
Bullet lowered his gaze to his hands.
In dragon form, his five fingers became killing claws.
If those claws could be empowered like the scales...
"I understand."
He said.
That afternoon, Bullet stepped onto the deck for the first offensive test.
His partner was Shanks.
"Mister Bullet, are you really going to use that new move?"
Shanks gripped his sword, both excited and nervous.
He had heard the noise from the lower deck. He knew Bullet had broken through something again.
"Be careful."
Bullet only gave him three words.
His right arm shifted into Black Scale Armament.
He did not stop there.
He drove the energy into his fingers.
The claws began to change.
They were not just sharp anymore. Along the edges, dark gold light flowed like a thin layer of enchanted steel, as if each claw was a named blade.
"Here I come."
Bullet stepped in and swung his right claw.
No flourish, just the most basic horizontal slash.
But the speed was so great it tore out afterimages in the air.
The claw ripped through the wind with a screaming whistle.
Shanks' pupils shrank. He instantly raised his sword to block.
Clang.
In that moment of impact, it felt to him like his blade had struck an entire mountain.
A colossal force surged down the sword, tearing open the skin of his palm. Blood splashed out from his tiger's mouth.
At the same time, a small chip appeared on the sword edge.
That was the blade Roger had given him. It might not be a Supreme Grade sword, but it was still forged by a famed smith.
Shanks staggered back three steps before he managed to steady himself.
He looked down at the damaged edge, then up at Bullet's dragon claw, where dark gold still flowed like liquid metal.
"...Monster."
He muttered, though there was no fear in his eyes, only a fiercer fighting spirit.
"But I will not lose to you."
They kept sparring.
As they exchanged blows, Bullet became more and more familiar with how to use Black Scale Armament offensively.
He discovered that in this state, his claws were not just sharper and tougher.
They carried a penetrating force.
Even if his attack was blocked, a portion of the impact would pierce through the defense and crash into the opponent's insides.
After half an hour, the spar finally ended.
Shanks was drenched in sweat, his sword hand trembling, but there was a satisfied grin on his face.
"So strong, Mister Bullet."
"You too."
Bullet replied.
He could feel clearly that Shanks' swordsmanship had improved noticeably over the last few days.
Pressure really did accelerate growth.
When the sun sank in the west, Bullet went back down to the lower hold.
This time he did not continue training.
He sat down cross legged and closed his eyes in meditation.
The birth of Black Scale Armament was not just a breakthrough in technique.
It was a revolution in how he fought.
He began to understand that devouring and evolving did more than give him raw power.
It pointed him toward a path that belonged to him alone.
A path where Nidhogg's body was the vessel, Haki was the bone, and Devour was the soul.
Outside, the New World's night had only a few scattered stars.
Bullet opened his eyes and raised his right hand.
With a thought, the dark gold lines surfaced beneath the skin, glowing faintly in the dark.
"Black Scale Armament..."
He whispered the name and allowed a small smile to appear at the corner of his mouth.
"Not a bad name."
Far away at the helm, Rayleigh stood by the wheel.
Through the porthole he looked toward the lower decks, his eyes full of quiet satisfaction.
"Roger, this little monster you dragged aboard..."
"He might really change this world."
He murmured, then lifted his gaze to the stars.
The prologue of a new era had already, quietly, begun to turn its first page.