The lowest deck of the Oro Jackson.
Normally this space was crammed with spare sails, ropes, and repair tools, but today a section had been cleared, leaving a bare patch of floor.
Rayleigh stood in the middle of that open area beside a metal device half as tall as a man.
It looked like an oversized navigation compass, its surface engraved with intricate geometric lines. Three differently colored gems were set into its center.
Bullet stood in front of it, bare chested in only black trousers. He could feel a faint ripple of energy coming off the thing.
"What is this?"
He asked.
"A piece of an ancient device."
Rayleigh ran his hand over the metal casing.
"We found it in some ruins. It was originally a weather regulator, used to adjust climate."
"But I discovered that if I only activate its core gravity module and keep the output on the low end..."
He pressed a switch on the side of the device.
Hum.
A low vibration filled the air.
The blue gem among the three lit up with a soft glow.
Bullet immediately felt his body grow heavier, as if invisible hands were pressing him down.
"We are at two times gravity now."
Rayleigh said.
"How does it feel?"
Bullet rolled his shoulders and moved his neck.
"I can feel it, but it is nothing special."
Rayleigh smiled and pressed the switch again.
The blue light brightened and the green gem lit up as well. The hum deepened.
Bullet's knees bent a fraction on their own.
Now it felt like someone his own weight had jumped onto his back.
"Four times gravity."
Rayleigh said.
"Training in this environment will put much greater strain on your muscles, bones, and organs."
"But if you adapt, when you go back to normal gravity, your speed, strength, and explosive power will all improve by a full tier."
He walked over to the wall where three water buckets had been set down. Each bucket was filled to the brim, a single leaf floating on each surface.
"Today's training has three stages."
Rayleigh pointed at the first bucket.
"First stage, physical adaptation."
"Under four times gravity, you will do basic drills. Squats, push ups, sit ups, two hundred sets each, one hundred reps per set."
"The movements must be clean, and your breathing cannot fall apart."
He pointed to the second bucket.
"Second stage, precision control."
"You will wrap your finger in Armament Haki and, without touching the water, cut that leaf in half from a distance."
"The leaf cannot sink and the water cannot spill."
Finally, he pointed at the third bucket.
"Third stage, pressure test."
"While gravity continues to increase, you will attempt partial dragonization and maintain it for three minutes. I want to see how stable your ability is under extreme conditions."
Bullet listened, then nodded.
"Got it. Let's begin."
Rayleigh stepped back to lean against the wall.
"The gravity field is already on. You can withdraw at any time."
"But remember, once you step out, you are done for today. Your body needs time to adjust to changes in pressure."
Bullet did not bother to answer.
He was already walking to the center of the cleared floor. He planted his feet shoulder width apart, drew in a deep breath, and began his first squat.
His movements were slow.
Under four times gravity, every motion demanded far more muscle power than usual.
As he lowered his body, he could clearly feel his thigh muscles twitching, his knees bearing a tremendous load.
As he rose, his spine straightened one segment at a time, his core tightened to the limit.
One, two, three...
Bullet counted in his head.
By the fortieth set of squats, his breathing had grown heavy.
Under the crushing gravity, his lungs had to work much harder just to expand and contract. Every breath felt like someone was pressing down on his chest.
But he did not stop.
The ache in his muscles, the swelling burn in his joints, the oppressive squeeze around his organs, all of it only sharpened his focus.
He could feel the black core within him speeding up its rhythm under the stimulus, releasing more energy to nourish the muscle fibers.
The devouring power had activated passively.
He was not actively devouring anything external, but his body was converting stored reserves into fuel more efficiently.
At the eightieth set, his thigh muscles began to cramp.
He clenched his teeth and forced his body through each standard repetition.
Sweat had completely soaked his trousers and was already pooling on the floor beneath him.
Rayleigh watched quietly, eyes sharp.
He tracked every small detail, Bullet's breathing rhythm, the sequence of muscle recruitment, the way he held his center of gravity.
By the one hundred twentieth set, Bullet's vision started to darken at the edges.
That was his brain complaining about lack of oxygen.
He slowed his pace and adjusted his breathing, guiding more Haki up toward his head.
It was an application of the internal lining technique he had learned just yesterday.
The effect was immediate.
The dizziness ebbed, his thoughts cleared again.
At last, the two hundredth set of squats was done.
Bullet stood where he was, drawing big, rough breaths, chest heaving violently.
He rested for only ten seconds before dropping down for push ups.
This was harder.
Under four times gravity, his body weight was equivalent to four of himself.
Every descent felt like his triceps and chest were about to be torn apart.
Every push back up meant fighting not just mass, but multiplied acceleration.
At around the fortieth set, his arms started trembling.
Tiny gritty sounds came from his elbows as the ligaments complained under the strain.
He shut his eyes and focused his awareness on his arms.
The black core kicked into a higher rhythm again, but this time the energy it sent out was targeted, flowing directly into the muscles of his arms.
"Oh?"
Rayleigh's eyes narrowed.
"Self adjustment that strong?"
He had estimated Bullet would hit his limit somewhere around the eightieth set.
Clearly, he had underestimated him again.
Seventieth, eightieth, ninetieth...
By now Bullet's arms felt numb, yet his form remained perfect.
His will was a taut steel wire that refused to snap.
Finally, the two hundredth set of push ups ended.
Bullet rolled on his back and immediately started sit ups.
Under this gravity, his abs felt like a tightly hammered iron plate. Each crunch demanded effort from his entire body.
This was the final part of the basic drills.
By the time he finished the two hundredth sit up, three hours had passed.
He lay flat in a shallow puddle of sweat, chest rising and falling like a bellows, every muscle in his body twitching.
"Rest for five minutes."
Rayleigh's voice reached him.
"Then we move to stage two."
Bullet did not get up.
He used those five minutes solely for recovery.
The devouring core went fully to work, pulling in even the faint traces of free energy in the air.
It was almost nothing, but better than nothing.
Five minutes later, he pushed himself upright and walked to the second bucket.
The leaf drifted quietly on the surface of the water, rising and falling with the ship's slight sway.
Bullet extended his right index finger, Armament Haki wrapping up along it.
Under four times gravity, even forming Haki cleanly had become much harder.
Energy that usually obeyed his will like an extension of his body now moved sluggishly, like thick syrup trying to flow.