7. The Body Transformation Project

Chakra is a unique energy formed by the fusion of spiritual and physical energies within the cells of the human body. Generally speaking, a ninja experiences rapid growth in chakra from childhood through adolescence into adulthood, coinciding with physical development and mental maturation. Once adulthood is reached, this growth gradually slows. As ninjas age, their bodies weaken or their spirits falter, causing their chakra to diminish significantly.

Typically, most ninjas graduate from the academy at age twelve, and the years before adulthood constitute the most critical period of growth in their lives. Naruto Uzumaki and Nagato both began to show their strength around twelve, rising to the pinnacle of the ninja world within just three or four short years.

However, Nagato, during his youth, not only expended vast amounts of chakra to sustain the Rinnegan, but also suffered early disability in his legs, preventing him from fully developing his potential. By comparison, Naruto’s situation was much better, though his childhood was marred by poor nutrition—subsisting on expired instant noodles and milk—which stunted his physical development and made him the underachiever of the academy in the early days.

Kisame, on the other hand, stood out from his peers from an early age, enjoying smooth and rapid growth. If not for his lowly status, he would have been promoted to Chunin long ago. At age twelve, Kisame’s starting point was higher than both Nagato and Naruto.

Therefore, he resolved to learn from their experience and mistakes, adopting a scientific training method to fully unlock his own potential. That method was physical fitness.

Fitness, in the world of Naruto, is a common form of training. The Land of Lightning boasts the most fervent fitness culture—streets are filled with muscular, dark-skinned men, and the Raikage is a fitness fanatic, with barbells and dumbbells in his office. Konoha also has its own fitness enthusiasts; Might Guy and his father often run hundreds of laps around the village, followed by thousands of push-ups and kicks, exhausting themselves.

Kirigakure has a fairly large gym as well, frequented by many ninjas for training.

In his previous life, Kisame practiced both street fighting and was a fitness devotee, persevering for over a decade and benefiting greatly. Despite being nearly thirty, he looked as youthful as a high school student.

His reason for choosing fitness, aside from building muscle, was this: after devouring the Thunder Blade "Fang," his body’s capacity was nearing its limit. He realized that to absorb more ninja swords, he needed a stronger physique.

Thus, fitness was imperative.

Kisame was decisive and wasted no time. Early in the morning, he went to the central gym, registered at the front desk, and became a long-term member.

Entering the equipment area, he was greeted by the unmistakable scent of hormones—or more bluntly, sweat. The gym was far from luxurious, even somewhat shabby: grimy, stained walls, flickering lights, and old, rusted equipment, all in a rather rough style.

Kirigakure’s humid climate meant the equipment was prone to corrosion, creaking loudly at the slightest touch, but at least the selection was comprehensive enough.

Having eaten ten eggs that morning, Kisame began his workout promptly. He started at the dumbbell rack, and after testing, picked up a pair of fifty-kilogram dumbbells, lay down on the bench, and skillfully completed several sets of presses and flyes.

Bang!

After finishing his last rep, Kisame tossed the dumbbells to the floor and sat up, frowning slightly. He felt his chest muscles engorged and torn, but not intensely so.

In his previous life, a fifty-kilogram dumbbell press was the mark of a gym legend, worthy of competition. But for twelve-year-old Kisame, it was too easy, with little effect.

Clearly, he was still too reliant on old experience, not pushing his limits.

In his past life, an adult human body contained between thirty to forty trillion cells. In the Naruto world, a typical body has one hundred thirty trillion cells—three to four times as many. For a monster like Kisame, the count is likely even greater.

Moreover, with his body’s recovery abilities, he needn’t worry about overtraining or muscle breakdown.

So, Kisame revised his fitness strategy: if you don’t train to death, train as if you might.

With this philosophy, he dramatically increased the weights and began his second round. In the vast gym, Kisame sweated alone, clashing fiercely with every piece of equipment.

The morning flew by.

“Hah!”

Kisame let out a long breath, drenched in sweat as he left the gym and returned home.

His lunch consisted of several pounds of beef, a basin of milk, and heaps of vegetables.

Although his home was shabby, his father had left a small inheritance, and Kisame had accumulated some savings from two years of missions, so he wasn’t worried about food for now.

After eating, he squinted and napped for half an hour.

In the afternoon, he didn’t return to the gym, but went instead to a riverside grove to practice taijutsu and ninjutsu.

In this world, ninja taijutsu comes in many styles—Iron Fist, Gentle Fist, Ninja Taijutsu, and others—but Kisame’s practice belonged to none of these.

He decided to incorporate the techniques of street fighting from his previous life into his taijutsu, gradually forming a complete system.

He called it "Unrestricted Taijutsu."

What is Unrestricted Taijutsu? For example: before a duel, you slip laxatives into your opponent’s food to weaken them, then disturb their sleep by banging drums outside their door at night, and the next day, drive a dump truck through the crowd to finish them off.

That’s Unrestricted Taijutsu.

Unrestricted Taijutsu is rooted entirely in real combat: when fighting an enemy, the first thoughts are ambush, trickery, and deceit—these despicable tactics are often the most effective.

Kisame’s previous methods—throwing lime, low blows, wild dog assaults—all fall under Unrestricted Taijutsu.

He realized that in this treacherous and perilous ninja world, Unrestricted Taijutsu had immense potential.

Thus, Kisame circled the grove, found a tree trunk as thick as a barrel and taller than a man, fixed it to the ground, and made a wooden dummy.

He stared at it, imagining it as the mortal enemy who slaughtered his entire family—a foe not to be tolerated. Soon, anger and hatred boiled within him.

His face flushed red, and rage, hatred, and murderous intent interwove in his heart like a volcano about to erupt.

“Damn!”

Finally, Kisame cursed and, like a mad dog, launched a violent assault on the dummy.

Eye gouging, nose digging, low kicks, knee strikes, takedowns—

All manner of brutal, vicious moves were used.

Such training enabled Kisame to instantly enter a "mad dog" state in battle, unleashing terrifying killing intent and seizing the initiative.

Crack!

Under the intense training, the dummy finally broke, splitting in two under Kisame’s onslaught.

Satisfied, Kisame clapped his hands. That was enough taijutsu for today; next was ninjutsu practice.

Suiton—Water Style—was his absolute forte.

Throughout the history of the Naruto world, Kisame’s talent in Water Style ninjutsu was among the very best, rivaled only by a handful such as Tobirama Senju, Hanzo, and Gengetsu Hozuki.

Swish, swish, swish.

By the riverbank, Kisame swiftly formed hand seals, summoning a translucent blue shark.

Water Style: Water Shark Bomb.

This was Kisame’s signature ninjutsu, shaping chakra into a shark-shaped water bullet to attack enemies. He could also envelop himself in the water bullet and glide through the air.

With a thought, Kisame slipped inside the shark water bullet and soared skyward. After circling in the air, he dove like a guided missile into the river, sending up a massive splash.

Immersed in water, Kisame felt utterly at ease, as if he’d returned home.

After swimming for a while and confirming he was alone, he dove to the riverbed. His lightning-imbued shark tail flicked out from behind him.

Zzzzz…

Underwater, lightning crackled. Kisame swam with his tail, fierce and swift as a human-shaped shark, moving at dazzling speed.

In water, his combat power multiplied; even surrounded by enemies, he could easily cope or escape.

This made Kisame realize the importance of fighting in environments favorable to himself. If there was none, he would use Water Style to create one.

Ninjutsu practice lasted until dusk.

Aside from taijutsu and ninjutsu, Kisame was also intrigued by genjutsu, sensing its value for sneak attacks. Unfortunately, he had no talent for it and had to give up.

Night fell, stars scattered across the sky.

Kisame wrung out his clothes after leaving the water and returned home.

He ate twenty egg whites in one go, with some carbohydrates, then dragged his exhausted body to bed for an early rest.

The next morning,

Kisame was shocked to find the soreness in his body had vanished without a trace.

Ordinarily, recovery times for human muscle groups are twenty-four to forty-eight hours for small muscles, seventy-two hours for large ones, but Kisame had returned to peak condition overnight.

Despite yesterday’s intense training, even his chest muscles were no longer sore.

Looking in the mirror, he saw both pectorals visibly larger.

Such talent was nothing short of a fitness prodigy.

From then on, Kisame trained every muscle group each time he visited the gym, not sparing even the smallest ones.

His training intensity increased daily, soon leaving all others in the gym far behind.

The gym resounded with low shouts and the clang of metal.

A group of Kirigakure ninjas gathered, casting furtive glances at Kisame, who trained alone in the corner, whispering among themselves.