Yasa left the residential area and returned to the forest covering the other half of Birka Island.
Having stolen Enel's fruit and returned it, he felt he'd done his part. No regrets.
Now he could shed all burdens and focus on training in the forest.
He couldn't neglect his daily exercises—his physical condition would be crucial in the future. Yasa swung his fists with all his strength, each punch whipping up dried leaves and twigs from the Island Cloud above.
Sweat flew everywhere, but he didn't care. He was completely absorbed in the thrill of his growing strength, letting his clothes soak through.
"My Rumble-Rumble Fruit is still at its basic stage. To become stronger, I need time to refine it. What methods can I use to enhance my power?"
Even as he trained, Yasa pondered other questions. The physical exertion wasn't enough to distract him.
"Electric currents can stimulate muscle and bone cells, making the body stronger. Should I try that?"
The thought suddenly struck him, and his eyes lit up. He decided to give it a go.
In his previous life, he had enjoyed watching various anime. One Piece was his favorite, but he'd also seen Naruto.
The Raikage from Naruto used a family-secret technique to enhance his physical strength through lightning!
Once this thought took root, it wouldn't be contained. Yasa's hands paused in their exercises.
"I must try this method. Failure won't matter, but if it works... I could even challenge Kaido and Whitebeard in the future!" His eyes burned with terrifying intensity.
However, this method was extremely dangerous, with constant risk to life. It would require careful experimentation over time.
The Raikage's secret technique was family-inherited. His ancestors must have spent generations refining it, passing down knowledge through each generation, until they developed this unique enhancement method.
But Yasa was different. Having eaten the Rumble-Rumble Fruit, he could control lightning. He could precisely regulate the flow of electricity, allowing him to rapidly develop this technique. Over time, surpassing the Raikage seemed inevitable.
The experiment was extremely dangerous. Yasa had to handle it personally. If anything went wrong, death would be inevitable.
For an ordinary person, electrocution usually occurs when the current passing through the body exceeds safe limits.
Once this threshold is crossed, the lungs stop breathing, and the heart's muscle loses its ability to contract. This leads to ventricular fibrillation, where the heart's "blood pump" fails, stopping circulation throughout the body.
With blood circulation halted, cells quickly become oxygen-deprived. Within 10-15 seconds, consciousness is lost. After a few more minutes, nerve cells begin to fail, ultimately leading to death.
These were basic principles Yasa understood well. In his previous life, he was an electric welder who frequently worked with electricity.
The severity of electric shock depends on several factors: the current's strength, voltage, resistance, duration, path through the body, and individual physiology.
When 1 milliampere (thousandth of an ampere) of current passes through the body, a person feels a needle-like sensation. At 10 milliamperes, the shock becomes unbearable, causing physical reactions.
At 20 milliamperes, human muscles begin to contract. If the current continues, it can lead to death. At 50 milliamperes or more, even a brief exposure can be life-threatening.
Yasa's physical condition has transcended human limits—he's essentially a superhuman. With such enhanced constitution, his body can withstand higher currents, so he can safely increase the initial test voltage.
But don't forget: while current is dangerous, voltage is equally lethal!
Higher voltage means greater risk. Most people can safely handle 36 volts or less. Beyond that, there's a real danger of electrocution.
The longer the exposure, the greater the danger. When someone can't break free from the power source, their muscles quickly weaken. This can lead to heart failure, suffocation, unconsciousness, and ultimately death.
Yasa had no such concerns. As a master of lightning, he could control the thunder at will. If anything went wrong, he could stop the current instantly.
The Rumble-Rumble Fruit had a technique called Electrotherapy, which could revive the dead by stimulating the heart with electric current. If Enel could develop such a monstrous ability, why couldn't Yasa use electricity to strengthen his muscles and enhance his physique?
He found a comfortable position and carefully began to manipulate the lightning, ensuring his body didn't enter Elemental Transformation. He started experimenting gradually.
Of course, Yasa didn't dare to test his initial experiments directly on his body. He focused the transmitted current on his pinky finger, sealing off all other areas to prevent the electricity from spreading.
Just a pinky finger. If it gets damaged beyond repair, I can simply chop it off. It won't affect my combat ability. There are plenty of ways to recover on the high seas. But if I use it on my body, any organ or tissue damage could put me on the brink of death. At that point, I'd have no chance to find a doctor.
He gradually increased the current, carefully monitoring the changes in his pinky finger...
Time flew by, and before they knew it, a month had passed.
"Success at last!" Yasa exclaimed, nearly leaping up in excitement from his perch on a thick tree branch.
After a month of trials, he could clearly feel that his left pinky finger was now stronger than his right one—not just in terms of power, but also in flexibility and dexterity.
"Hahahaha! Finally, I can safely enhance myself with electricity. Kaido's title as the strongest creature across sea, land, and sky should rightfully belong to me!" Yasa's face lit up with exhilaration.
Over the past month, he had continuously increased the voltage of the electric current. During one accident, his left pinky finger nearly burned to charcoal. Only through quick Elemental Transformation did he avoid losing the digit.
Now that the experiment had succeeded, his body would be constantly strengthened by the electric current. Soon, he would reach the terrifying level where a punch could shake mountains and a kick could stir the Four Seas.
Zzzt-zzzt-zzzt!
The faint hum of electric current flowed through every corner of Yasa's body under his control, reaching even his bones. Only his fragile internal organs remained isolated.
He didn't dare take risks with his organs now—a single mistake could be fatal. But Yasa believed there would come a day when even his internal organs could be enhanced. When that happened, a superhuman with no weaknesses would be born.
His skin, muscles, and bones gradually grew stronger. The tingling sensation made Yasa's body tremble involuntarily. He glanced around, slightly embarrassed. Good thing no one was nearby—if they had been, he'd have had to kill them to keep this secret.
This feeling was even more comfortable than soaking in a hot spring. His entire body felt pleasantly numb. Yasa relaxed and quietly enjoyed the sensation.
PS: The part about electricity and voltage was taken from wikipedia.