Underground Training

Darkness, boundless darkness.

Icy river water poured wildly into Rain's nose and mouth, carrying his battered body through the twisting underground waterways.

Rain's left shoulder wound, deep enough to expose bone, had turned pale from soaking in the river. His right arm, drained dry by Crocodile and shriveled like dead wood, drifted helplessly with the current.

"Glug glug..."

The intense suffocation made Rain instinctively open his mouth and gulp down the freezing underground river water.

Then, at that very moment, a miracle happened.

Rain's shriveled, necrotic right arm, which had even lost all sensation, was fully submerged in the clear freshwater. As Rain drank deeply, its desiccated cells began madly absorbing water like Cracking Dryness earth finally receiving rain after a long drought!

"Creak... creak..."

Accompanied by the faint stretching of muscle fibers, the bark-like skin visibly began to fill out again. Shrunken blood vessels swelled, and atrophied muscles regained their vitality.

In just a few minutes, the right arm that Sand Crocodile had nearly crippled miraculously recovered its original slender, powerful form beneath the nourishment of the river water!

"Splash—!"

Rain abruptly thrust his head above the surface and greedily gulped down the thin, damp air of the underground cavern.

He raised his fully restored right hand. A flicker of shock passed through his dark eyes, followed by understanding.

"Who would've thought running for my life would bring me something this good... Sand Crocodile's 'drying' isn't irreversible necrosis. It's extreme dehydration. As long as there's enough water, the body can rebuild itself." Rain clenched his right fist, feeling the surging strength return.

With a thought, Rain's legs instantly transformed into gray-white Granite beneath the water. Rather than crumbling beneath the water's embrace, they became exceptionally sturdy.

This was an unexpected windfall! In this sunless underground world, without the sea's absolute suppression, he, a Rock-Rock Fruit user, was still a monster capable of controlling stone.

"Crocodile, you thought throwing me into hell would kill me." A bone-chilling smile curved Rain's lips. "What you didn't know was that this underground river happened to neutralize your killing move."

Rain stopped drifting with the current. Using his Devil Fruit power, he transformed his legs into streamlined rock propellers and swam deeper underground with the flow, moving through the rushing river like a nimble black fish.

He had no idea where this underground river led, but his keen senses told him that the temperature of the water around him was changing.

The originally bone-chilling river water gradually turned warm as he continued diving and drifting, eventually becoming almost scalding.

A strange, dark-red glow faintly emerged from the darkness ahead.

"Rumble—"

The sound of rushing water became incomparably violent. Rain was swept by a powerful suction force into an enormous underground waterfall, plunging straight down from midair.

"Bang!"

Rain instantly transformed into a mass of solid rock in midair, crashing heavily onto a scorching black reef before reforming his human shape.

When he got to his feet and saw the sight before him clearly, even someone accustomed to death and wonders couldn't help but suck in a cold breath.

This was a naturally formed, colossal cavern deep beneath Alabasta.

The underground river cascaded down from above, but the instant it reached the cavern floor, the terrifying heat vaporized it into billowing white high-pressure steam.

At the very center of the cavern, there was no water and no sand.

There was only a dark-red lake, churning and bubbling like a living hell.

It was magma from deep within the mantle.

The horrific heat had baked the cavern walls red. The air was severely distorted by the extreme temperature. Just standing here, Rain felt as though his hair and eyebrows were about to catch fire.

"The edge of an underground volcanic magma chamber..."

Rain stared at the magma lake radiating destructive heat, the leaping dark-red flames reflected in his black eyes.

After his brief shock, an uncontrollable fervor and ambition ignited within his chest like a wildfire.

He remembered the humiliation of being completely crushed by Crocodile amid the desert ruins.

"Stone will eventually become sand. Your power is merely a part of my desert."

Sand Crocodile's arrogant taunt still echoed in his ears.

"You're right. Sand is weathered rock. In terms of physical properties, you do counter me." Rain removed the black trench coat that had been ruined by the water and was now smoking beneath the heat, then slowly walked toward the deadly magma lake.

His upper body was bare. The blade wound on his left shoulder, deep enough to expose bone, no longer bled in the heat. Instead, it had formed a layer of dark-red scab.

"But it seems you've forgotten, Sand Crocodile. The ultimate form of rock isn't a pile of loose sand."

Rain reached the edge of the magma lake. Heat sufficient to instantly melt metal and stone scorched his skin.

He slowly extended the right arm that had just been reborn in the underground river.

"If ordinary stone can't break through your defenses, then what if... it's liquid stone over twelve hundred degrees, capable of melting everything into glass?"

An utterly savage, crazed glint flashed through Rain's eyes.

He was not only cruel to his enemies. He was even more ruthless toward himself.

"Logia Rock-Rock Fruit development—"

Without any protective measures, Rain directly drove his slender, pale right arm into the churning dark-red magma without the slightest hesitation!

"Sizzle—!"

An ear-piercing sound of flesh being instantly carbonized exploded through the empty cavern!

A beastlike growl tore from Rain's throat. Veins bulged across his forehead, and beads of sweat evaporated the moment they formed. The agony of plunging living flesh into magma was a hundred times crueler than being cut by a thousand blades!

Yet he did not pull his arm back.

Through the unbearable pain, he forced his eyes open and used his nascent Observation Haki to lock onto and sense the deadly fluid engulfing his right arm.

"Calm down... feel its structure... feel its pulse..."

Rain's mind raced madly beneath the extreme heat. Magma, at its core, was silicate rock in a molten state. Its essence was still stone; it only contained such horrifying thermal energy that its molecular structure had entered an exceptionally active, violent, free state.

If the Rock-Rock Fruit could compress molecular gaps to increase density and create indestructible High-Pressure Obsidian, then conversely, if he actively made the molecules within rock undergo extreme friction and violent vibration, could he create heat beyond all limits and turn solid stone back into a liquid sea of fire?

"If it's all stone... then move for me!"

Rain gritted his teeth so hard that blood seeped from his gums. Rather than using ordinary rock to defend against the magma, he forcibly abandoned all resistance and began squeezing every last bit of Devil Fruit power from his body to actively "match" and "imitate" the violent molecular vibration frequency of magma.

At first, the bones in his right arm were burned red, and the pain nearly tore his soul apart.

But as every second passed, the madness in Rain's eyes did not fade. Instead, it grew hotter and brighter. He gradually adapted to the world-destroying temperature and gradually felt the fluidity of liquid rock, as natural as moving his own arm.

"So that's how it is... Only by breaking the shackles of solidity can one reveal the earth's true power."

Rain suddenly began to laugh softly. His laughter echoed through the empty cavern, sending chills down the spine. He instantly spread his understanding of the magma state outward with wild abandon!

"Hum—!"

Starting from the shore where Rain stood, the hard walls of the underground cavern around him suddenly emitted a deep resonant hum.

Driven by the newly awakened power of the Rock-Rock Fruit, the cold Granite that had cooled for millions of years began heating up at a visible rate.

The rock surfaces changed from gray-white to dark red. Then, under the extreme heat and the frenzied vibration of their internal molecules, they forcibly melted into viscous dark-red magma that reeked of sulfur, dripping into the lake drop by drop!

He had completely mastered the key to transforming rock into magma.

"Assimilate!"

Rain unleashed a Sky-Shaking roar.

The newly generated magma around him, along with the originally violent earthfire within the lake, encountered the same-origin yet more dominant pull of the Rock-Rock Fruit. Like a hundred rivers flowing into the sea, they surged backward along Rain's right arm.

Taking the bones of Rain's arm as their core, they frantically coiled, fused, and reshaped themselves.

Gray-white Granite served as a buffer, while black High-Pressure Obsidian formed an indestructible framework, repeatedly tempered beneath extreme heat.

A Flame Demon Arm, radiating blinding dark-red light, with scorching lava flowing over its surface and ultra-dense Obsidian supporting its interior, was fully taking shape within this hell at the earth's core!

"Sand fears water? No, sand fears the furnace of high heat even more!"

Rain looked at the magma right arm now connected to his bloodline, one that seemed capable of incinerating everything with a casual swing. A wild smile curled his lips.

"Wash your neck and wait, Crocodile. When I crawl out of this hell, I'll use this furnace to burn your desert into a wasteland carpeted with shattered glass!"