Armament Haki Breakthrough: Thunder

At the center of the training ground, the aftermath of lightning and iron fists continually detonated through the air with deafening blasts, and the entire field shook as if being torn apart by two colossal beasts.

The two figures were nearly impossible to follow with the naked eye. All that could be seen were streaks of slanting lightning and afterimages of jet-black Armament Haki colliding madly.

After dozens of consecutive clashes between fists and feet, Zephyr finally understood that Rock was not merely showing off.

It was a carefully considered fighting style that perfectly made use of his Devil Fruit's properties.

Electricity crackled continuously over Rock's body. Every movement of his muscles came with precise electrical stimulation, multiplying the activity of his muscle fibers.

Zephyr was shaken. "Using electricity to stimulate his muscles, enhancing his body's elasticity... even pushing his reaction speed to the limit..."

"So that's how it is... He came up with such a use at such a young age?!"

The corners of Zephyr's mouth lifted slightly. The next instant, his aura surged sharply!

—Armament Haki poured through his veins like an inky sea!

His shoulders, arms, fists, and fingers were all coated in black, like perfect weapons forged by a master weaponsmith.

"Brat Rock! I admit that you're very impressive!!!"

His foot shattered the ground beneath it, and his powerful body vanished in an instant!

"—Soru!"

A black shadow raced low across the ground like a tiger pouncing through the grass!

Lightning burst around Rock, and his reaction kept up at once as he raised an arm to block!

Bang!!!

Both of them were knocked back, but Rock's attack did not stop. Lightning exploded again!

"Kami-e: Flash!!"

Zephyr's body continuously twisted and dodged amid the exploding lightning, his limbs as nimble as paper as every one of Rock's lightning strikes brushed past him.

Rock's eyes lit up. "The Six Powers? Interesting..."

—Lightning suddenly erupted!

"Lightning Step: Flash!!"

His footsteps left trails of lightning behind them, his speed rising to its absolute limit!

The two figures chased and collided, sending rings of shockwaves bursting through the air above the training ground!

"Geppo!!"

Zephyr kicked off the air and leaped upward, transforming into a black cannonball that plummeted from above toward Rock's head!

"Bring it on!!!"

Rock gathered lightning in both hands, and a ring of electricity violently expanded outward!

"Lightning Burst—!!!"

Boom!!!

Zephyr charged out of the lightning, his right leg black as a blade!

"Rankyaku: Rending Wind!!!"

Several Armament Haki-infused cutting winds slashed down from above!

Rock crossed his arms, instantly erecting a wall of lightning!

The instant their techniques exploded in midair, the ground seemed to have been swept by a hurricane! Broken stones, smoke, dust, and sparks flew everywhere!

"Shigan: Piercing Iron!!!"

The smoke and dust exploded apart as Zephyr lunged in close, his five fingers thrusting straight at Rock's chest like steel spears!

Lightning patterns spread across Rock's body, and his Lightning Armor instantly thickened!

Bang—!!!

The Shigan, condensed with extreme Armament Haki, struck the Lightning Armor and burst into electric sparks. Both men were blasted backward at the same time!

Zephyr stared at his fingertips in surprise. "It actually couldn't pierce through? The Lightning Armor is hard enough to withstand Armament Haki?!"

Rock licked the corner of his mouth, excited like a wild beast. "Zephyr, you're strong—"

"But I won't lose either!!!"

The two charged at each other once more!

"Tekkai: Steel!"

Zephyr hardened his entire body, turning himself into a living weapon as he countered with an elbow strike!

Rock's lightning blazed fiercely. His muscles instantly tensed as lightning surged across his body, swelling his muscles in an instant and raising his strength another level!

The two clashed fist against fist again!

Boom—!!!

A huge section of the training ground was forcibly crushed into collapse!!

The sound of fists and kicks colliding was like war drums, rhythmic yet violent, making the soldiers feel as if their hearts were pounding along with it.

Bang!!!

Boom!!!

After dozens of consecutive clashes between top-tier Armament Haki, a faint layer of black gradually spread over Rock's fists.

At the sight, Sengoku's glasses nearly slipped to the tip of his nose, and his pupils shrank sharply. "His Armament Haki... broke through?!"

Even Tsuru could not hide her astonishment. "He comprehended Armament Haki enhancement by force in this kind of direct clash?!"

Garp was already laughing so hard he could barely breathe. "Hahahaha! I told you that brat was a monster! Do you believe me now!!"

But merely breaking through did not mean he could immediately catch up to Zephyr.

The difference in strength between their Armament Haki was still enormous.

"Ha!!!"

Zephyr suddenly exerted force, delivering a heavy kick to Rock's abdomen as though smashing iron!

Thud—!!!

Rock was kicked flying, his body smashing through the ground and creating a pit several meters deep. The entire field shook!

The soldiers cried out, "Vice Admiral Zephyr is getting serious!!"

"That kick... It hurts just watching it!!!"

Without giving him time to catch his breath, Zephyr used Soru and instantly arrived before him!

His figure vanished from the air, appearing above Rock's head the next moment!

"Haah!!!"

His steel-black Armament Haki-clad leg carried enough force to shatter a rock wall as it crashed straight toward Rock's face!

Rock raised his arm and blocked it head-on!

Bang—!!!

The force was so great that Rock's entire arm instantly went numb!

The moment Zephyr landed, he followed up with a storm of punches, forcing Rock back strike after strike!

"Your lightning truly is powerful!"

"But your Armament Haki is still far too lacking!!!"

Covered in battle wounds, Rock panted under the gale-like pressure, yet the corners of his mouth still curled into a smile. "Yeah... In close combat, you've really had me pinned down."

"But—"

He abruptly raised his eyes, azure lightning flickering deep within his black pupils.

Sengoku's heart tightened outside the field. "This brat... He's changing tactics!!"

Seeing this, Zephyr roared, "It's over!!!"

His fist flew toward Rock like a cannonball. Just as that iron fist was about to strike—

Rock stopped moving, a slow grin spreading across his face. "Zephyr."

"Don't forget—"

"I'm lightning itself."

The next instant.

Bzz—!!!

Rock's body suddenly shattered into countless threads of lightning!

Zephyr's killing blow of an iron fist passed through the lightning and struck nothing but air!!

Zephyr's pupils trembled. "He actually turned into an element at a time like this...!!?"

Behind him.

Crackle—!!!

The lightning reformed into Rock's complete figure!

He rose into the air, hovering above the training ground as lightning poured from beneath his feet like flowing water.

Rumble—!!!

High above, dark clouds began gathering at a speed visible to the naked eye!

They rapidly spread!

They swallowed the training ground!

They swallowed the headquarters building!

They swallowed all of Marineford!!

The soldiers on duty far off at the harbor looked up, their faces turning deathly pale. "W-What... The entire sky suddenly went dark?!!"

"Is this a natural phenomenon?!!"

Sengoku's breathing visibly stopped for half a second. "These aren't ordinary thunderclouds...!"

Tsuru looked at the lightning silhouette floating in the sky, shock rising in her eyes. "This is practically... a natural disaster..."

Zephyr slowly raised his head. Lightning illuminated his face, making the iron-blooded vice admiral reveal genuine shock for the first time.

"An influence on this scale...?!!"

Lightning gathered into thick thunder serpents that roared and darted through the dark clouds.

Standing high in the sky, Rock raised one hand, and the entire heavens answered with a thunderous roar.

He spoke slowly, his voice not loud, yet it rang through the entire field.

"Zephyr—"

"You'd better be careful from here on out."

Thunder roared, and heaven and earth changed color.