Chapter 13: Development of a New Jutsu
Before Nan and Kakashi could begin developing their new jutsu, there was something important to clarify:
Even though the techniques they aimed to create were similar, they were fundamentally different in nature—one was a ninjutsu, the other a taijutsu.
What Nan needed was a lightning-infused taijutsu style, similar to the Lightning Release Chakra Mode passed down through the Raikage lineage.
Nearly all shinobi knew how to enhance their speed and strength by coating their limbs with chakra. This was the foundation of taijutsu.
However, Lightning Release Chakra Mode took this further—it involved replacing the regular chakra coating with chakra infused with the lightning nature.
Lightning chakra had the unique property of stimulating the body, granting the user bursts of speed and explosive power.
It worked on the same principle as elemental ninjutsu being more powerful than neutral, non-elemental techniques.
But while the theory sounded simple, putting it into practice was another story entirely.
Standard taijutsu used non-elemental chakra, which was harmless to the user.
Lightning Release chakra, on the other hand, was volatile and difficult to control—especially when applied directly to the body. If mishandled, it could even prove fatal.
To use lightning-infused taijutsu effectively, one needed not only a deep understanding of the Lightning Release nature and near-perfect control but also an incredibly strong body capable of withstanding prolonged exposure to high-voltage chakra.
This is why so few shinobi ever developed or used such techniques—only those with monstrous physical endurance, like the Raikage, could wield them without hesitation.
Kakashi's Chidori, however, was a different matter.
Although it also relied on lightning chakra to enhance the user's speed, Chidori was fundamentally a high-speed assassination jutsu.
Its destructive power came from the massive amount of lightning chakra focused into the hand, turning it into a deadly piercing strike.
The burst of speed was merely a means to an end—to ensure the technique connected with its target.
Unlike Nan's envisioned taijutsu style, Chidori didn't require sustained speed or strength. It only needed to work once—just long enough to land the hit.
This short burst of stimulation was far less harmful to the body. That's why Kakashi, despite lacking the Raikage's freakish physique, was able to develop Chidori on his own. Of course, his natural talent played a big role too.
Which of the two techniques—Chidori or Lightning Chakra Mode—was stronger was difficult to say.
In the original story, the Raikage seemed more formidable than Kakashi, but that was largely due to his sheer physical prowess.
His destructive power came from raw strength, enhanced by lightning.
From a damage amplification perspective, Chidori was superior. But in terms of stability and sustainability, Lightning Chakra Mode had the edge.
One thing both techniques shared was their stimulation of the nervous system through lightning chakra. Even the Raikage couldn't afford to convert all his chakra into Lightning Release.
When using Lightning Chakra Mode, most of the chakra coating the body remained non-elemental, with only brief flashes of electricity dancing across the skin.
It wasn't like Sasuke's Chidori Stream, where the whole body crackled with lightning.
If one infused too much lightning chakra directly into the body—completely replacing neutral chakra—it would result in instant death, even for someone as durable as the Raikage.
Let alone for Nan and Kakashi.
And so, the core goal of their collaboration was this:
To determine the optimal ratio of lightning-infused to neutral chakra for body enhancement.
That is, how to maximize cellular activation and boost physical performance without damaging the body.
Nan's role was crucial in this phase. Using his knowledge of medical ninjutsu and human anatomy, he would calculate the most effective way to apply lightning chakra for physical enhancement while minimizing the risk of injury.
Kakashi, in turn, would draw on his extensive experience with Lightning Release to adjust and fine-tune the chakra transformation process based on Nan's data.
Once they completed this foundational step, their paths would diverge:
Kakashi's goal was to develop a high-output Lightning Release jutsu capable of gathering a massive amount of chakra into his palm to deliver a single, devastating strike.
Nan's focus was on reducing the physical risks of long-term Lightning Release usage and syncing the chakra flow more seamlessly with taijutsu movements.
At the same time, Nan would need to continue honing his chakra control to better handle the demands of prolonged Lightning Release activation.
Once they finalized the development plan, Nan and Kakashi immediately began the first stage:
Testing the effects of Lightning Release on physical stimulation.
Unlike their previous training sessions where Kakashi led the way, this time the experiment was driven by Nan's medical data.
Of course, Nan intentionally fudged a few non-critical variables...
As a result, Kakashi ended up suffering quite a bit more than necessary.
When the lightning chakra surged through the wrong pathways and struck sensitive spots, Kakashi ended up rolling on the ground, screaming in pain.
Watching Kakashi writhing in agony, Nan couldn't help but let out a few quiet, sinister chuckles.
Then he composed himself and put on a concerned expression.
"Oh dear, Kakashi, are you all right? It's all my fault—I must have mixed up some of the data by accident. I'm so sorry you had to go through that."
Because back when Kakashi had been teaching Nan Lightning Release, he'd deliberately made things unpleasant for Nan, and had been extremely strict.
Nan had never quite let that go. He hadn't wanted to lash out in the moment, but now that the opportunity presented itself, he was determined to get a little payback.
Still lying sprawled on the ground, Kakashi saw Nan apologizing so sincerely and couldn't bring himself to be angry. Instead, he forced a wry smile and reassured him:
"It's fine. Let's just keep at it."
He slowly sat back up, and Nan stepped forward to use medical ninjutsu, treating the damage and fatigue caused by repeated Lightning Release stimulation.
Seeing Nan so concerned, Kakashi never suspected that this was deliberate revenge for how harsh he'd been during Nan's Lightning Release training. He genuinely believed it was just an accidental miscalculation.
Nan, meanwhile, felt quite pleased with himself.
When he saw Kakashi not only fail to notice anything, but even show a trace of gratitude for the treatment, he thought smugly:
"None of you ninja who didn't even go through nine years of compulsory education can possibly imagine just how deep my tricks run."
Not only had he secretly taken his revenge, but he'd even made Kakashi thank him for it. Poor Kakashi had no idea he'd been played like a fiddle.
Of course, Nan wasn't truly malicious—he'd only tampered with a few non-critical parameters that wouldn't leave any lasting damage.
Besides, Kakashi had definitely studied the basics before he set out to develop Chidori himself. If Nan altered anything too obvious, Kakashi might start to suspect something.
And with Nan's excellent medical skills, there was no way Kakashi would suffer any serious harm.
Most importantly, Nan couldn't afford to let Kakashi get knocked out completely—without him, his own progress in developing new jutsu would be delayed.
The development of their new techniques was proceeding in an orderly fashion—until a small interruption set them back slightly.
That day, Nan and Kakashi were working as usual, experimenting and recalculating data, when suddenly a loud voice called out:
"Come and fight me, Kakashi!"
Even without looking up, Nan immediately knew who it was.
Who else but Might Guy, the man who had sworn to treat Kakashi as his lifelong rival?
Sure enough, as soon as Kakashi heard that voice, his expression darkened into weary resignation.
Guy had been clinging to him since childhood, always pestering him for a duel whenever he had the chance.
At first, Kakashi had thought that beating him a few times would discourage him enough to go away. But to his dismay, Guy was absolutely indomitable.
Kakashi had lost track of how many times he'd defeated him—but no matter what, Guy never stopped challenging him.
He'd finally managed to dodge him for two whole months by going on missions, and then staying cooped up developing new techniques so Guy wouldn't have an opportunity to show up.
Kakashi had hoped to enjoy a few more days of peace, but to his horror, Guy had tracked him down even here.
With a screech of brakes and a cloud of dust, a young man in a sleeveless green bodysuit, sporting an absurd bowl-cut hairstyle and the thickest eyebrows imaginable, made his dramatic entrance—Might Guy himself.
Guy thrust his thumb skyward at Kakashi.
"At last, I've found you! Let's have a hot-blooded duel of youth!"
Beaming, he flashed a dazzling smile so bright that his gleaming teeth nearly blinded Nan and Kakashi.