That day,
The sky was clear, the sun was shining.
East Blue.
Goa Kingdom, Foosha Village.
Behind the mountain.
A three-year-old boy, drenched in sweat yet filled with determination, was pushing himself to the limit. Beads of sweat, the size of soybeans, rolled down endlessly from his forehead.
"Drip. Drip."
Sunlight poured from the horizon, illuminating the boy's small body.
Though he still looked like a child, faint outlines of muscle had already formed on him—living proof of his relentless training.
That lean, youthful frame, despite its size, carried a wild, explosive strength, like that of a tiger ready to pounce.
As he continued his push-ups, the boy muttered under his breath, counting without pause:
"Nine hundred and ninety-five!"
"Nine hundred and ninety-six!"
"Nine hundred and ninety-seven!"
...
"One thousand!"
Finishing his thousandth push-up, Kai collapsed onto the lush green grass beside him. His limbs ached with exhaustion, the soreness flooding through his body.
The breeze was gentle, the clouds drifting.
Kai closed his eyes slightly, staring at the boundless blue sky above.
The cool touch of the grass against his back soothed him, relaxing his entire body. Weariness surged through him, making him want nothing more than to drift into sleep.
"Three years… it's been three years since I came to this world."
"Even now, it still feels like a dream."
Every time he reached this level of exhaustion, Kai would recall that day three years ago, when he inexplicably crossed over into this world—
reborn as a newborn infant.
That's right!
Kai was a transmigrator, through and through.
In this day and age, the concept of transmigration wasn't unfamiliar to him.
But what he never expected was…
the world he'd crossed into—
was the perilous world of One Piece.
When the truth sank in, Kai's emotions were complicated.
Fortunately, he had a strong adaptability. He quickly accepted this new reality.
In the years that followed, he gradually uncovered his identity.
"I… actually became the son of Monkey D. Dragon, the founder of the Revolutionary Army? The son of the man labeled the most dangerous criminal in the world?"
"And my grandfather… is Monkey D. Garp, the so-called Hero of the Marines?"
"And soon, I'll have a younger brother about to be born—Luffy?"
With such a glorious bloodline, anyone else would have been ecstatic.
But for some reason…
Whenever he thought of his soon-to-be-born brother Luffy, with his reckless and carefree personality, Kai could only imagine the endless trouble that kid would stir up on this treacherous sea.
It gave him a massive headache.
Still, he had no choice but to accept it.
Over the past three years, apart from the time of his birth when he caught a glimpse of his mysterious father Dragon, Kai had never seen him again.
Which meant—
For these three years, Kai was raised entirely by Garp.
And under Garp's inhuman "training," he had survived countless brushes with death, sharpening both his body and his will. From the edge of life and death, he forged wild instincts, strength, and an iron will to survive.
Though only three years old, he was already a small yet genuine powerhouse!
In Foosha Village, one could say—he was virtually unmatched.
Garp's training method was brutally simple…
He would often toss Kai alone into desolate wilderness, calling it "training his survival skills," when in truth, it was just because Garp was too lazy to babysit.
That Kai was still alive today… was nothing short of a miracle.
"Soon… Luffy will be born," Kai thought, narrowing his eyes.
In these three years, he had fully adjusted to his new identity.
And without exaggeration, he now had one of the strongest backgrounds in the entire world!
But… this same background would also bring him endless trouble and disasters in the future.
So, very early on, Kai made a decision—
He had to become stronger!
Luckily…
as a qualified transmigrator, how could he possibly not have a system?
"I, Garp's grandson… have a system!"
A bright smile spread across Kai's face.
He silently commanded in his heart:
"System, display my status panel."
The thought no sooner formed than—
a translucent screen appeared before his eyes.
[Host: Kai]
[Strength: 4.1]
[Speed: 3.9]
[Stamina: 4.3]
[Ghost Back Completion: 9.99%]
[Cultivation Efficiency Multiplier: x10]
[This training session yielded: Strength +0.02, Speed +0.01, Stamina +0.03]
The system Kai awakened was called the Ghost Back System.
Its purpose? To make him stronger, and forge a perfect Ghost Back upon his body!
Through endless training,
his Ghost Back would gradually be perfected.
That was the system's primary goal.
At the same time, the Ghost Back System also provided him with support.
For example—
it boosted the efficiency of all his training!
In other words, every bit of cultivation he did was amplified tenfold.
That was the true power of the Ghost Back System.
And this tenfold boost was merely because his Ghost Back Completion Rate had reached 9.99%.
Once he broke past the 10% threshold…
his cultivation efficiency would skyrocket once again!
At that time…
Would it be fifty times?
A hundred times?
Or even hundreds, thousands of times stronger?!
Just imagine—
a boy like Kai, already born with monstrous talent, now wielding a system that multiplied his growth by hundreds or even thousands.
Given time…
How terrifying would his strength become?
What others gained from ten years of training—
Kai might achieve it in a single day!
At that moment, the system's mechanical voice rang out again:
[After amplification by x10, this training session yields…]
[Host gains: Strength +0.2, Speed +0.1, Stamina +0.3]
The moment the voice fell, a warm current surged through Kai's body.
It coursed through his organs, bones, and blood, enhancing every aspect of him.
A massive surge of strength filled him.
In an instant, his status panel had shifted again:
[Host: Kai]
[Strength: 4.3 (+0.2)]
[Speed: 4.0 (+0.1)]
[Stamina: 4.6 (+0.3)]
[Ghost Back Completion: 9.99%]
[Cultivation Efficiency Multiplier: x10]
This was the reward of his tenfold boost.
For comparison, an ordinary human's average stat was only "1."
Meaning…
At the age of three, Kai already possessed strength, speed, and stamina far beyond a grown adult man.
Without exaggeration—
a three-year-old Kai could flatten dozens of ordinary adults with one hand!
"Almost there!"
"The Ghost Back Completion is about to break 10%…"
"At that time…"
"My cultivation will soar again!"
Kai's eyes gleamed with anticipation.
Deep in his heart, he had a strong premonition—
Once the Ghost Back broke through 10%,
his current tenfold cultivation boost… would transform into a world-shaking leap in power!