Ziyun bit off a quarter of the Rumble-Rumble Fruit in one big mouthful. He nearly threw up, but managed to hold it down.
It tasted so damn awful it was almost like eating shit.
No... Ziyun didn't actually know what eating shit tasted like, but he couldn't think of a better way to describe it.
Then, with tears in his eyes, Ziyun finished the Devil Fruit.
"Um... host... actually, according to the rules of Devil Fruits, you only need one bite to gain the power. The rest of the fruit turns into ordinary fruit."
The system couldn't watch anymore.
"Then why didn't you say so earlier..." Two clear streams of tears ran down Ziyun's face.
"Hehe, you have to make the mistake once before you can avoid making it again." The system sounded rather pleased with herself.
But the system's voice was so pleasant that Ziyun couldn't bring himself to scold her.
After eating the fruit, Ziyun felt a wondrous change in his body. A force surged ceaselessly within him, as though a devil really were roaming around inside.
Of course, Ziyun knew it wasn't a devil, just the fruit's power.
He willed it to appear, and faint bolts of lightning began crackling around him.
Then Ziyun went to the training ground in the laboratory.
The laboratory had an enclosed training ground so that Ziyun could test the results of his ninjutsu experiments whenever he wanted.
In fact, the laboratory could have passed for a luxury villa in the world of Naruto. It had a bedroom, a yoga room, a living room, a kitchen, and more, all so Ziyun could devote himself entirely to researching ninjutsu.
That showed just how much importance the Third Raikage placed on Ziyun.
After arriving at the laboratory, Ziyun took a deep breath and held out one finger, copying the way Kizaru fired lasers in One Piece.
He thought the way Enel unleashed his attacks was too sleazy, while Kizaru looked much cooler, so he copied him instead.
They were both Logia powers anyway, so there shouldn't be a problem.
Crackle!
Sure enough, a beam of blue lightning burst from Ziyun's finger the next moment and smashed a training dummy made of special materials to pieces.
"Not bad in terms of power, but I'm not very proficient with it."
Ziyun couldn't help muttering to himself. The lightning hadn't struck the dummy he had aimed at; it had veered slightly off course.
It seemed he wouldn't become invincible the moment he ate the fruit. If he wanted to do what Enel had done in the original, he needed to get more familiar with it.
But there was something that pleasantly surprised Ziyun: the Rumble-Rumble Fruit had displayed considerable power.
Even that clumsy attack just now had been no weaker than a C-rank ninjutsu.
If he developed it further and learned Enel's 200 Million Volts: Amaru from the original...
Then its power would presumably rival that of Super Shinra Tensei, the Tailed Beast Ball, and the Great Spiralling Ring of Fear in Naruto. A single attack would be enough to level a ninja village.
But developing it would take time. After all, Ziyun's reward hadn't been delivered directly into his body for him to master immediately; it had come in the form of a fruit.
It seemed this was a power he would have to develop step by step himself.
After that attack, Ziyun's system changed as well. A proficiency value had appeared after the words "Rumble-Rumble Fruit," currently at 3%.
"What's this progress about?" Ziyun noticed it too and asked the system.
"It works like this: Devil Fruit proficiency increases as the host develops the power. At 30%, you can use moves. At 70%, you can use the power proficiently. At 80%, you can unleash ultimate moves. At 100%, the fruit will awaken."
The system thoughtfully answered Ziyun's question.
"Can I increase my proficiency just by training?" Ziyun asked.
"In theory, yes. But without actual combat, your proficiency will stop increasing at 70% at most. To awaken the fruit and comprehend ultimate moves, you can only rely on fighting," the system replied.
"Anyway, I'll train it up to 30% first."
Ziyun nodded, then used the Lightning Release: Shadow Clone Technique to create several Shadow Clones to help him train.
Ziyun had learned this ninjutsu himself through hard work. With Shadow Clones, he could learn ninjutsu faster.
So four or five Ziyuns began familiarizing themselves with the power in the training ground.
They started with the basics, discharging electricity from their bodies, then moved on to lightning. After a few hours, Ziyun was fairly familiar with the fruit's power.
Finally, Ziyun tried moving in elemental form. He was extremely fast... comparable to the Third Raikage with his Lightning Release Chakra Mode activated.
Unfortunately, because his proficiency was insufficient, Ziyun couldn't move at the true speed of lightning like Enel.
And if he went too fast, his body couldn't take it either.
"Looks like I need to strengthen my body further," Ziyun said to himself. He opened the system panel and saw that his Rumble-Rumble Fruit proficiency had already climbed to nearly 12% in that short time.
"Next, I should learn to use a move."
Ziyun dispelled his Shadow Clones and watched his proficiency shoot up to 30%. He felt he could now learn to unleash more powerful moves.
With a thought, he felt the power of lightning coursing through his body. The next moment, a dazzling bolt of lightning erupted from him.
"2 Million Volts: Hino!"
Ziyun couldn't be bothered to name his moves, so he simply used the name Enel had already given it in the original.
The lightning bursting from his body transformed into a giant bird in midair and soared with its wings spread.
"Not good, my control isn't quite there!"
Ziyun realized he was in trouble. He hadn't developed the Rumble-Rumble Fruit's power nearly enough. Instead of firing from his fingertip as he'd intended, electricity was discharging from every part of his body, somewhat beyond his control.
A rumbling filled the entire laboratory, and lightning spread across it, as though some giant monster had invaded.
Some of the Anbu standing outside the laboratory could even see the escaping lightning with the naked eye.
"What's going on? Could someone be attacking the laboratory?"
The Anbu on guard duty noticed the strange commotion. After exchanging glances, an Anbu with some sensory ability immediately began forming hand seals to investigate.
"It looks like there's no one in the laboratory except Ziyun..."
The sensory ninja shook his head. There probably wasn't an intruder.
"But that's an enormous commotion! What if a ninja with some secret technique that can block sensory detection has invaded?"
Sensing something was wrong, several Anbu exchanged glances and decided to go inside and see what was happening.
The commotion was simply too great. Without the strength of an elite jonin, it would be hard to cause such a disturbance.
If anything happened to Ziyun and the Third Raikage blamed them, they couldn't bear the consequences.
"Oh no... intruders! We have intruders!!"
"Quick, report to Lord Raikage!"
After entering the laboratory, the Anbu were terrified.
Lightning was discharging wildly throughout the entire laboratory. The terrifying sight made them wonder if they were caught in a genjutsu.
A Lightning Release ninjutsu with such an enormous range... only an S-rank ninjutsu could produce an effect like this.
Anyone capable of using ninjutsu on that level could only be a jonin or even an elite jonin.
So they instinctively assumed there must be an intruder and began shouting.
"Quick... get out, it's dangerous! Don't come in... no one's attacking! Get out of here!"
Hearing the Anbu, Ziyun hurriedly called out. He still hadn't mastered control of the lightning, and it could easily injure someone by accident.
But as soon as he spoke, Ziyun realized it was already too late. A brilliant bolt of lightning flew from his body and careened wildly about. He couldn't call it back even if he wanted to.
The bolt struck the Anbu, injuring them and knocking them to the ground.
Immediately afterward, the lightning flared.
Above the entire Hidden Cloud Village, a mass of heavenly lightning came rumbling down and struck the laboratory where Ziyun was, causing a massive explosion.
"Hey, did you see that just now?"
"I... I saw it. That bolt of lightning... it was terrifying!"
"Anyone hit by that would probably die, wouldn't they?"
Meanwhile, several Konoha ninja who happened to be on a mission in the Land of Frost, a neighboring country of the Land of Lightning, saw a flash of white light. A massive bolt of lightning, like the wrath of a god, struck within the Land of Lightning. They reckoned it had landed where the Hidden Cloud Village was located.
"Could that genius from the Hidden Cloud Village be developing another new ninjutsu?"
Then one of the jonin spoke up, as though something had suddenly occurred to him.
Yeyue Ziyun's talent for creating his own ninjutsu had reached the ears of other ninja villages, and he had become quite well known. Otherwise, Konoha wouldn't have sent people to raid the Hidden Cloud Village's laboratory.
"No... that's not very likely, is it? A ninjutsu like that has to be close to S-rank. How could a ten-year-old brat create such a terrifying technique?"
Another chunin found the idea absurd and argued back.
"But... that huge lightning bolt just now didn't look like a natural disaster at all. Could the Hidden Cloud Village's tailed beast have gone on a rampage?"
"Either way, let's report this to Lord Hokage first."
The Konoha ninja looked at one another and saw the gravity in each other's eyes.
Konoha Village, inside the Hokage's office.
The Third Hokage, Hiruzen Sarutobi, sat upright in the Hokage's chair, smoking a large pipe. He held a scroll containing intelligence sent back from the Hidden Cloud Village.
Yes... it concerned the huge explosion Ziyun had caused.
Hiruzen Sarutobi was now in his prime, full of vigor, and his hair was still black. He had the bearing of a formidable leader and was worthy of the title of Professor.
Of course, that was only how he appeared to those who didn't know the truth.
After reading the intelligence and pondering for a moment, Hiruzen Sarutobi looked up at Danzo Shimura, who was also in his prime, and the two elders, Koharu Utatane and Homura Mitokado, beside him.