One Piece: With Sign-in System

Amidst the Thunderclouds, lightning crackled and thunder roared in a chaotic symphony. Within the core of the dense, tumultuous storm clouds, a figure engulfed in blackness hovered in mid-air. His body, shrouded in arcs of electricity, endured the relentless punishment of countless bolts of lightning striking him from all directions.

His right leg glowed with a dazzling golden hue as immense lightning energy poured into it. Golden arcs of lightning entwined his leg, weaving a radiant net of power before coursing through his entire body, tempering his hardened physique infused with Armament Haki.

Inside, Ron's vitality surged like a torrential river breaking through a dam. His vitality, stagnant at 3,400 for a long time, began climbing rapidly under the furious tempering of the storm's energy.

3,407… 3,408… 3,409… 3,410…

…

On The Traveler, Conis lay on the deck, peering nervously into the dark, swirling mass of thunderclouds below. Her face was a picture of worry.

"Will the captain be alright? That's pure lightning down there!"

Robin, standing nearby, nodded slightly, concern etched on her face. "Even with Armament Haki to defend, enduring such a dense barrage of lightning isn't something anyone can handle for long…"

"Master…" Enzo's young face mirrored their anxiety.

Bonney, leaning against the mast with crossed arms, clenched her fists tightly, her nails nearly digging into her palms.

"He'll be fine," a calm and steady voice interrupted.

They turned to see Kuina, clad in her white training attire, her arms bearing heavy steel bracers. She gripped an enormous steel barbell, practicing vertical strikes with unwavering focus.

"That's Ron we're talking about—our captain. No matter how insane his actions seem, he always strides toward his goals with unwavering determination. I trust him completely, and so should you."

Sweat dripped from her soaked bangs, plastered against her face, but her expression remained resolute.

"This is the New World—the most dangerous seas of them all. The foes we'll encounter from here on out will only grow stronger. Instead of worrying about him, focus on your own strength. We can't always rely on him to carry us."

Conis, Robin, and Bonney fell silent, Kuina's words echoing in their minds.

"I… I'm heading to train," Enzo declared, turning toward the gravity chamber.

Conis and Robin exchanged smiles before nodding.

"She's right. We didn't come aboard to be pretty ornaments!"

"It's time the world saw the true strength of the 'Calamity from the Skies' Crew as well!"

"No way we're letting the captain steal all the spotlight!"

The three women quickly began their respective training regimens, focusing on three key areas: Haki, breathing techniques, and Devil Fruit mastery.

…

Three Days Later.

A charred figure fell from the stormy heavens, plummeting into the dense thunderclouds below before slamming into the ground with a deafening crash. The impact obliterated a small mountain on the lightning-cloaked island.

[Ding! Detected location: Raijin Island. Eligible for sign-in rewards. Sign in?]

"Sign… Sign in."

[Ding! Sign-in successful. Rewards: +10 Vitality, +50% Lightning Resistance.

50% Lightning Resistance: Reduces damage from lightning-based attacks by 50%.]

A blinding bolt of lightning tore through the skies and struck the massive crater. The charred figure lying within—Ron—shuddered as arcs of electricity danced across his body.

3,539… 3,540… 3,541…

…

[Ding! Skill Upgrade: Essence of Strength (Lv4). Temporarily boosts strength by 40% when activated, consuming vitality.]

3,561… 3,562…

…

Two more days passed under the relentless onslaught of lightning.

[Ding! Skill Upgrade: Ultimate Kick (Lv3). Concentrates immense power into the right leg for a devastating strike, increasing destructive force by 300%.]

As the system notification echoed, Ron's lips curled into a faint, exhausted smile.

"It… finally leveled up."

His body, numb and ravaged, barely moved as he muttered the words. He cast a healing spell on himself, but the effect was minimal. A second attempt provided slight relief, but he still couldn't muster the strength to rise.

A charred, humanoid figure resembling a piece of burnt coal lay flat on the scorched ground. Above him, lightning rained down incessantly, shrouding the island in a cacophony of destruction.

His battered body teetered on the edge of collapse.

"Seems… I underestimated the forces of nature…" His voice was weak, his mind flickering in and out of focus.

From the system space, he retrieved a small, unassuming green bean—an item gained from an earlier sign-in reward. Summoning his remaining will, he popped it into his mouth and chewed.

The moment the bean entered his body, an overwhelming surge of energy flooded his every cell. His mangled body regenerated at an extraordinary rate, muscles knitting together, vitality soaring. In just seconds, his depleted stamina and mental strength were fully restored, as though he had never endured the grueling trials of the past five days.

Ron opened his eyes, their depths blazing with newfound determination.

"Let's see what this power can really do."

The peculiar energy's effects faded, but due to the devouring abilities of his eyes, Ron's stamina and mental energy were stabilized at two-thirds capacity.

"No wonder they call it a Senzu Bean... It's a pity I've only gotten two of these after all this time. Now there's only one left. I'll have to save it for a critical moment."

Emerging from the deep crater formed by relentless lightning strikes, the charred figure of Ron slowly stood upright. With a slight shake, the thick, blackened crust encasing his body shattered.

Like a caterpillar breaking free from its cocoon, Ron stood transformed.

Inside the pit, his towering frame now reached two meters. His physique was muscular yet proportionate, with defined lines radiating sheer power. His hair, regrown from the peculiar energy of the Senzu Bean, now cascaded down to his waist, billowing wildly in the fierce winds.

BOOM!

Another lightning serpent streaked down from the heavens, aiming to smite him once more.

Ron, eyes still closed, didn't even flinch. He raised a fist and struck forward.

The immense vitality coursing through him, enhanced by Level 6 Armament Haki, combined with the formidable Level 4 Essenceof Strength, unleashed a terrifying synergy.

The punch cracked the air like shattered glass, leaving visible ripples in its wake.

The devastating force collided with the thunderous serpent.

CRASH!

A deafening explosion reverberated as an overwhelming shockwave obliterated the nearby terrain, flattening the surrounding hills. The massive lightning bolt, fragmented under the impact. Its remnants scattered as smaller bolts, striking the scorched earth and leaving behind countless craters.

Ron, bathed in blood-colored steam, his eyes still shut, exhaled lightly.

With his strength restored, he muttered, "I'm stronger than I was back on Drum Island. No... perhaps I've surpassed even that."

It had been a risk, but the rewards were undeniable.

"System, display my current stats."

[Host: Ron]

Age: 18

Vitality: 3569

Transparent World: Level 4

Sun Breathing Technique: Mastery 100%

Swordsmanship: Breath of All Things; Grandmaster of Swordsmanship

Essence of Strength: Level 4

Signature Move: Ultimate Kick — Level 3

Sealed Power: Tenseigan Eye (Sealed) 

Devil Fruit Ability: Enhanced Float-Float Fruit (Second Stage, No Side Effects)

Permanent Buff: True Essence of a Thousand Tempers (Bound)

Lightning Resistance: 50%

Haki Proficiency:

Armament Haki: Level 6 (Second Stage)

Observation Haki: Level 5 (Second Stage)

Conqueror's Haki: Level 4 (Second Stage)

Combat Techniques:

Shave: Level 10

Moonwalk: Level 10

Tempest Kick: Level 10

Weapons:

Great Grade Blade: Raikiri

Great Grade Blade: Shusui

Blades: Oto, Kogarishi

Special Skills:

Mastery in Mechanics, Navigation, and Linguistics

Level 2 Healing Arts and Purification Techniques

Artifacts:

King's Treasury

Endless Wine Flask

Silver Revolver (Six Bullets per Day)

Unique Items:

Senzu Beans (x1)

…

As he reviewed his attributes through the system interface, Ron retrieved a fresh set of clothes from his storage space and dressed himself.

"My abilities and techniques are well-rounded. There aren't any obvious weaknesses... but when facing top-tier powerhouses like Kizaru, I still lack a definitive edge."

The power of his Ultimate Kick was undeniable, but landing such a strike was no easy feat. Moreover, this move represented Ron's ultimate technique. If he unleashed it without ensuring a decisive blow, the resulting exhaustion would leave him vulnerable and defenseless.

"That's why... back on Drum Island, I didn't unleash that kick on Kizaru."