One Piece: sign-in to Ryujin Jakka

A dark shadow surged from the sea beneath the moonlight, as if intending to swallow the entire battleship in one bite.

Countless torrents of seawater cascaded off the shadow's body, smashing into the ocean surface with thunderous splashes, kicking up massive waves.

Fortunately, Roman had used the power of his Rooster Talisman to lift the battleship into the sky, clutching Hancock tightly in his arms to protect her.

At the same time, the two girls on the ship rushed out in a panic.

"Big sister, what's happening!?"

Seeing Hancock safe in Roman's embrace, they immediately sighed in relief.

The moonlight illuminated the massive black figure, revealing its true form to Roman and the girls—it was a Sea King, so enormous that even with only its head emerging from the water, it easily exceeded a thousand meters in length.

Judging by that alone, its full body could easily be over five thousand meters long.

A creature like this would be a nightmare even for an Admiral.

Hancock, still held protectively in Roman's arms, narrowed her pupils in shock.

She grabbed Roman's sleeve urgently. "Roman, this is the legendary Deep Sea Serpent King from the myths of Amazon Lily! They say that once it reaches maturity, it can grow to over five thousand meters long!"

Hearing this, Roman grew even more intrigued by the fabled creature.

"I didn't expect something like this to still exist in the vast ocean."

The serpent's presence had captured Roman's full attention.

Once the ship had reached a safe altitude, he gently released Hancock and said, "Since it's a creature from legends, I'll go test its strength myself."

Without another word, Roman leapt from the battleship, leaving Hancock and her sisters behind.

The night was clear and quiet, the moonlight pure and bright.

As Roman fell through the air, strong winds whipped around him, causing his cloak to flap wildly.

There was no need for introductions when facing a Sea King.

Midair, Roman unsheathed Ryūjin Jakka, flames erupting from its blade and leaving a brilliant streak of fire across the sky.

The dazzling light immediately caught the attention of the massive serpent below.

The sea churned. Towering waves rose.

The Sea King's massive tail broke through the surface with tremendous force, whipping toward Roman from the depths like a carp reaching towards the heavens.

Though it looked slow, the sheer speed and power behind it were terrifying!

Hancock, watching from the ship's railing, gasped.

"Roman—be careful!"

Almost as if he heard her, Roman's eyes sharpened. He sensed the movement below.

"For anyone else, this would be troublesome—but unfortunately for you, you ran into me."

"All Things in the Universe, Turn to Ashes—Ryūjin Jakka!"

As his voice echoed across the sky, his blade ignited in radiant flames.

Torrents of fire surged skyward like a burning pillar.

Holding Ryūjin Jakka, Roman's eyes glowed with infernal light.

Upon releasing its full power(Bankai), the sword's flames could reach ten million degrees Celsius—the temperature of the sun's core.

Although Roman had yet to master that level, even its initial release(Shikai) was enough.

The temperature surged to six thousand degrees, matching the sun's surface. The restraints (Skikai)shattered.

For the first time since entering the One Piece world, Roman unleashed the blade's full potential.

Before he even reached the Sea King, the surrounding ocean began to boil.

"ROAR!!!"

Sensing the searing heat, the serpent grew even more ferocious. Its tail lashed out even faster.

In the blink of an eye, it was already upon him.

But Roman didn't flinch. He activated the Rooster Talisman's ability, accelerating his descent further.

Ryūjin Jakka erupted in a peerless blaze, transforming into a blade of molten light.

Simultaneously, six towering pillars of flame shot up from the sea, forming a storm of fire that pierced the skies. A gigantic crimson lotus of karmic fire bloomed ominously above the waves.

Millions of tons of seawater surged upward, forming towering tsunamis that roared like tens of thousands of dragons.

"Incinerate the heavens, boil the sea!"

With those words, Roman drove his blade straight into the serpent's eye.

A blazing slash burst forth—nearly a kilometer long—slicing straight from its head through its body.

The force of the strike blew open his cloak in the fierce wind.

The Sea King opened its massive mouth to roar—but it was too late.

Its entire body had been cleaved in two!

Blood, mixed with flame, dyed the sea crimson.

Onboard the battleship, Hancock stared wide-eyed at the inferno below. The ocean had become a literal sea of fire.

The sky itself had turned a glowing red from the blaze, and through it, she could see the ocean for thousands of meters boiling like a cauldron.

"So..so strong…"

Her eyes sparkled like stars.

In her heart, Roman was the strongest—no one could compare to him.

But when she turned her gaze to him again, she froze.

She had just seen him… remove his cloak.

—

The inferno in the sea could be seen from far, far away.

On Amazon Lily, the current Empress and captain of the Kuja Pirates stood within the palace, gazing toward the burning horizon in the Calm Belt.

Her heart sank.

"Just how powerful is the one who caused this…?"

And worse—it happened in the Calm Belt.

That could only mean one thing.

Their target might be Amazon Lily.

Her expression hardened.

"Prepare for battle!"

Amazon Lily's warriors, all skilled in both Armament and Observation Haki, immediately armed themselves.

Following the Empress's command, they spread into the jungle, lying in ambush along the fiery shoreline.

Elsewhere, not far from the burning sea…

A small boat slowly drifted on the water.

Onboard sat an elderly woman, shorter than average, her white wavy hair adorned with a flower. In her hand was a pet snake, coiled into a cane.

She stared ahead in shock.

"This flame… Could it really be him?"

She reached into the sea.

"Hiss—!"

The old woman gasped in pain, jerking her hand back.

"The water… It's scalding hot, even from this distance!"

She blinked in disbelief.

"This is terrifying…"

Sitting down, she barely lasted a moment before springing up again.

"Hot, hot, hot!!"

Anyone witnessing this scene would've surely found the sight hilarious.