Naval Six Powers

Water 7, the top-secret underground shipbuilding chamber beneath Dock One of the Galley-La Company.

This had originally been where Mayor Iceburg secretly stored important supplies. Now, with Robin's guarantee and the arrangements in his bag, it had become Rain's private place of rest and recuperation.

The floodgate of the underground canal slowly descended, completely shutting out the outside clamor and the Marines' manhunt.

Rain set the Seastone pack, weighing several hundred pounds, onto the dry stone floor, then removed his dark gray cloak, stained with dust and gunpowder smoke. For the next stretch of time, he would wait here for further improvements to the Bedrock while sorting through the gains from this operation.

The underground dock was far from quiet during the day.

"You want to add that much rock armor around the entire ship? Don't joke around! Even if it's hollow, the density of rock will ruin the hull's buoyancy balance. One wave, and it'll capsize!"

Several veteran shipwrights from the Galley-La Company crowded around Rain's preliminary modification plans for the Bedrock, arguing until their faces turned red.

"What if we use a honeycomb-like hollow internal structure?" Rain pointed at the waterline on the ship's underside in the blueprint. "With my Fruit ability, I can hollow out the Granite into countless separate diamond-shaped air chambers to provide buoyancy. At the same time, we can inject ultra-high-density Obsidian into the keel's stress points and the ram at the bow for counterweight."

The old shipwrights froze for a moment, rapidly working through the mechanical feasibility of the structure in their minds.

"Honeycomb air chambers... Wood could never achieve that level of sealing precision, but with your ability..." A bespectacled shipwright's eyes lit up. He slapped his thigh. "Genius! Not only would this guarantee buoyancy, it would multiply the hull's resistance to impact by orders of magnitude!"

Over the next few days, Rain's daytime life was almost entirely consumed by the complexities of shipbuilding.

He no longer viewed the [Rock-Rock Fruit] merely as a crude means of defense or attack. Instead, he began exploring material structures and fluid mechanics. He asked the shipwrights about the resistance ocean currents imposed on rudders, the optimal angle of a sail's load-bearing surface, and the critical resilience threshold of masts during extreme storms.

This knowledge, seemingly unrelated to combat, was priceless to Rain.

He knew well that the seas of the New World were treacherous and ever-changing, with abyssal waters wracked by lightning and hellish regions of extreme cold and heat. Only by thoroughly grasping the underlying principles of how a ship functioned could he use his Fruit ability at any time during future voyages to temporarily shape the Bedrock into a submarine, an icebreaker, or even a fortress capable of sailing through magma.

Knowledge was a hunter's sharpest claw and fang.

When night fell and the shipwrights left via the lift, the vast underground dock held only Rain and the Bedrock, which was gradually being reshaped.

A dim gas lamp swayed against the stone wall.

Bare-chested, Rain sat cross-legged on a smooth bluestone slab. He opened the waterproof document bag looted from Spandam's safe. Several yellowed parchment scrolls and densely handwritten notes lay before him.

These were the Naval Six Powers, the pinnacle of martial arts honed through eight hundred years of CP9 combat and passed down through generations. There was also an unexpected bonus: beyond the Six Powers, the documents included the even more profound Life Return.

Rain opened the first scroll, his gaze sharp as he studied the principles of force generation word by word.

He had originally thought that the Six Powers were simply methods for pushing the body to its limits. Yet as he read further, he discovered that the core of this martial art faintly corresponded to a method of circulating vital energy and blood, much like the profound internal martial arts of his previous life. That was why, even when Rain knew the principles behind certain techniques, he had been unable to reproduce them.

Rain opened the dossier and carefully studied the force-generation technique of Soru.

This was not a simple burst of brute force from the thigh muscles. During a brief deep breath, one had to compress the blood flow in the lower body to an extreme degree, causing high-frequency resonance within the muscle fibers of the soles. By stomping the ground dozens of times in an instant and using the recoil from the surging blood, the body could be launched like a cannonball.

Rain closed his eyes and mentally simulated this method of exertion. It was like a martial art that controlled the flow of blood within the body. The key was not how large a step one took, but the instantaneous unification of one's internal strength.

He rose to his feet, took a deep breath, and suddenly drove all his strength into his legs.

Bang!

The hard stone floor instantly exploded into a shallow crater. Rain's figure became a blurred afterimage, crossing dozens of meters of the dock in an instant before slamming heavily into the wall.

This had happened many times before. Before Rain obtained the cultivation method, he had also tried simulating it based on methods mentioned in his previous life. But either the speed increase had been minimal, or, like now, he could not control the distance or direction, making it useless in actual combat.

The dossier recorded the means to solve these problems, including how to control one's vital energy and blood, and which direction to exert force. With these techniques and his previous training, Rain would soon be able to grasp the basic workings of Soru and move through the underground chamber at high speed.

"This mobility is enough to make up for the clumsy movement I had when relying solely on rock defenses. But its practical combat applications still need further refinement, such as using my Fruit ability to alter the terrain..." A glint flashed through Rain's eyes.

Next came Iron Body.

According to the dossier, the principle of Iron Body was to control the heartbeat and breathing, forcing the blood flowing through the body into a momentary state of high-pressure "stagnation." Every muscle fiber in the body would lock tight, granting hardness comparable to steel.

This was practically an overbearing physical defense technique. A cold smile curled Rain's lips. For ordinary people, Iron Body's greatest weakness was that once their muscles locked, they could no longer move. But what if this extreme muscle-contraction technique were combined with his [Rock-Rock Fruit] assimilation?

Rain let out a low shout and forced his blood flow to plummet. The muscles all over his body instantly swelled and hardened, his veins bulging like coiled dragons. At the same time, gray-white stone skin rapidly covered his entire body. Under the high pressure created by Iron Body, it was continuously compressed inward, eventually emitting a deep, dark gleam like black diamonds.

"Still not enough. It doesn't even feel as strong as simply using Obsidian armor."

Yet he could sense the potential in this method. In the future, it might prove far more formidable than relying on his Fruit ability alone.

However, what truly made Rain feel as though he had found a priceless treasure was the thin booklet pressed at the very bottom of the dossier: "Life Return."