One Piece: Start with Zanpakutō

"First of all — Finger Gun."

Zephyr's figure shot out like an arrow, relying purely on physical strength. With just one finger, he pierced straight through a boulder on the beach as if it were paper.

"This is the Tempest Kick."

Lifting his right foot, he slashed it down toward the sea.

Whoooosh!

A sharp, ear-piercing sound tore through the air. A visible vacuum slash shot out like a flying sword, slicing both the beach and the ocean's surface in one clean line, leaving behind a deep, terrifying trench.

"This is Shave."

Zephyr appeared to take a single step, but in truth, he stomped dozens of times in a fraction of a second. His figure blurred, vanished, and reappeared fifty meters away, leaving only a cloud of swirling sand where he'd once stood.

"And this is Moonwalk."

He stepped into the air itself, as though invisible steps were laid out before him. Step by step, he climbed into the sky, then descended as if strolling down an invisible staircase.

"This is Paper Art."

Zephyr's body relaxed, shifting fluidly with the breeze. He seemed to become a thin sheet of silk, drifting and floating lightly on the sea wind.

"Finally… Iron Body."

With a single breath, all the muscles throughout his body locked tight and solidified like steel. From his skin down to every fiber of muscle, an unstoppable, fortress-like defense took form — tough enough to shrug off even a cannon shell.

However…

Rosen had watched the first five moves carefully, his eyes bright.

But when Zephyr demonstrated Iron Body, Rosen looked away in visible disdain, turning his head as though he'd seen something distasteful.

The so-called "Iron Body"?

Aside from giving its user a mysterious sense of false security, it had no actual function.

In the world of top-tier powerhouses who could split seas and shatter islands with a swing, did you really think some "iron-hard skin" would save you?

Those who actually relied on Iron Body as their main defense… Lost. Without exception.

"Have you learned them?"

After performing the Rokushiki in sequence, Zephyr turned to Rosen, his expression calm but his eyes watching closely.

If this were any other student — even an elite genius — Zephyr would have broken each technique down step by step and taught them one at a time.

But for Rosen?

Zephyr had chosen a full-speed, no-explanation demonstration.

Because with Rosen, words were redundant.

"I've learned them."

Rosen nodded without hesitation.

He had mastered the Three Forms of Haki and every advanced technique after hearing it explained once. The Rokushiki? Zephyr even performed them in front of him.

There was nothing to not understand.

"Don't underestimate the Rokushiki."

"Each move was designed by carefully studying the traits of Devil Fruits, swordsmanship, and weaponry."

"Tempest Kick was inspired by the swordsman's flying slash. Finger Gun mimics the piercing power of guns and cannons. Iron Body draws from the raw resilience of Zoan-type abilities. Paper Art imitates the fluid evasion of Logia users. Moonwalk and Shave are modeled after superhuman mobility abilities."

Zephyr glanced at Rosen's expression, clearly picking up his lack of respect — especially toward Iron Body.

"Alone, each technique seems mediocre. But what about when combined with your Three Forms of Haki?"

"Physical skills and Haki complement and reinforce each other."

"I taught you the Rokushiki because they are not only versatile combat techniques, but also excellent tools for training the body. Even after mastering them, repeating their practice will keep strengthening your physique — especially when combined with your Rokugan Rebirth (Six-Organ Rebirth)."

"Eating well, practicing vigorously — the two-pronged approach will let you forge a monster's body in the shortest possible time."

Rosen listened intently.

Especially that last sentence.

Finally, he stopped looking down on Iron Body.

He understood now:

Iron Body was not for defense — it was for pushing your body beyond its limits in training.

After all, against real top-tier attacks capable of shaking islands, no "Iron Body" could truly save you.

Those idiots at CP9, and certain naive navy recruits, always misunderstood it.

"This… is your last class at the Naval Academy."

"Starting tomorrow…"

"You no longer need to come here."

When Zephyr said this, Rosen paused, stunned.

"Teacher Zephyr… You mean… I'm graduating?"

Rosen's expression shifted as he realized what that meant.

Two days.

Four classes total.

Already… graduating?

But thinking about it carefully…

He had already learned all the Three Forms of Haki and every technique. He had grasped advanced physical skills and even created his own monstrous improvements.

What else could the academy possibly teach him?

Even Zephyr, a former Admiral and one of the greatest instructors alive, might not have much left to offer him.

"What are you thinking?"

"I only said there is nothing more you can learn at the academy."

"I didn't say you could graduate."

Zephyr shot Rosen a sharp look.

"If I don't come to class, but I'm not graduating… Then, where do I go?"

Rosen asked, confused.

"Tomorrow at 8 a.m."

"Wait for me at the entrance to the academy."

"Then you'll know."

Zephyr didn't answer directly, but turned around calmly, as though leaving Rosen hanging on purpose.

If it had been any other student — even someone like Sakazuki or Kuzan — they would have continued following scheduled group training every day.

But for Rosen?

There was no need.

It wasn't favoritism.

It was because Zephyr knew that at this stage, the most valuable gift for Rosen… was time to strengthen himself freely.

…

After class, Zephyr didn't return to the Zephyr class. Nor did he go check on Gion and Tokikake's Observation Haki training.

Instead, he went straight to the Marshal's office.

After knocking, he stepped inside and spoke a single sentence — and instantly, the entire room of high-ranking officers looked as though they'd been struck by lightning.

"What did you say?!"

"You want me to write you a free access pass… to Impel Down?!"

"Zephyr, what on earth do you plan to do there?!"

Sengoku stared, completely bewildered.

"In addition to the access pass…"

"I also want an indemnity warrant, signed personally by you."

Zephyr ignored Sengoku's reaction and calmly made a second request.

"Zephyr…"

"Are you planning to take revenge for your family…?"

Sengoku's expression darkened.

He remembered the tragedy that had shattered Zephyr's life.

The "Admiral with No Killings," who never once took a life during operations, had his entire family slaughtered by pirates.

From that day forward, the gentle "Teacher Zephyr" had died.

All that remained was an Admiral who despised pirates to the bone.

"If I truly wanted revenge, I would have stormed Impel Down long before I retired."

"There'd be no need to ask you for passes or indemnity signatures."

When Sengoku mentioned his family, Zephyr's face briefly twitched.

But it immediately returned to its usual steely calm.

"Then what… exactly… are you planning to do?"

Sengoku felt slightly relieved after hearing that, but he still refused to sign without understanding the full reason.

After all —

Impel Down was the fortress that held the most terrifying criminals and darkest secrets of the world.

No matter how much Sengoku trusted Zephyr, he could never simply sign off blindly.

...

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