Lightning-style chakra can stimulate cells, allowing them to relax rapidly, though this process naturally carries a certain amount of risk.
It requires extremely precise control to release chakra into the cells; otherwise, there is a very real chance of inadvertently electrocuting oneself to a crisp.
The reason he adopted this method was based on imagining the conditions in Kumogakure that had crossed his mind earlier, thereby crafting a training regimen better suited to himself.
As a member of the Uchiha clan, he didn't possess the protagonist's freakish regenerative abilities, so any methods he could devise had to be achieved through alternative means.
……
"Xiaokai, it looks like you've recovered really fast! Then let's keep fueling the flames of youth! Today's goal is still an 80-kilogram weight vest, running ten laps around the village before we move on to other training!"
The next day.
Uchiha Kai looked as though he had completely recovered and was feeling fine. Since he didn't have to go to the Ninja Academy today anyway, he simply ran over to Might Guy's place once again.
It was the same starting point, where the white starting line drawn a few days ago was still clearly visible on the ground.
"Oh! It is indeed time to fuel our youth, so I'll get started first!"
Uchiha Kai flashed a wide grin, took a deep breath, and immediately dashed forward in a single bound.
Seeing this, Might Guy was momentarily stunned before quickly matching his pace.
Compared to the previous run, his physical stamina had clearly broken through to a whole new level.
Running ten laps used to take a full day and would even leave him collapsed in exhaustion, but to his surprise, after just three days of rest, Uchiha Kai didn't even turn red or pant heavily during the first five laps.
His speed remained just as consistent as before.
This terrifying training capacity seemed as though he were simply born for Taijutsu.
Might Guy's eyes widened in disbelief; he hadn't imagined that a single period of progress could surpass his expectations by this much.
After all ten laps, although he was still exhausted to the point of collapse by the end, he completed it at least three hours faster than yesterday. Even though he was drenched in sweat and panting, he at least maintained his usual high spirits.
Inside the small woods.
After resting for a couple of days, Might Guy leaped straight up, somehow procuring several massive tree trunks. Carrying them in one hand, he soared into the air and forcefully drove the logs straight down into the ground.
Each of these logs was at least 50 centimeters in diameter and easily two to three meters long, yet once driven into the ground, only a little over a meter remained exposed.
"The next part of our training is two thousand punches against the tree trunks! If you can't manage that, it's one thousand push-ups instead! This is what youth is all about, so hurry up and get started!"
Might Guy grinned, flashing two rows of sparkling white teeth as he spoke.
"No problem!"
Sitting on the ground, Uchiha Kai popped up with a kíp-up, clenched his fists, and began striking the tree trunk at a blistering speed.
As night approached, Uchiha Kai was still hard at work doing push-ups—reaching the point where he couldn't even push himself back up from the ground, yet he still gritted his teeth and persisted.
……
"I really never expected that the Uchiha clan could produce an idiot who can't even use chakra, yet simultaneously turn out a Taijutsu genius. Who knows why their clan always produces people with such potential."
Since this grove was close to the outer perimeter of the village, the two of them constantly training like their lives depended on it naturally caught the attention of quite a few observers.
Not to mention Might Guy, whose strength was already known to most people in Konohagakure; even though he couldn't use Ninjutsu, there wasn't a single person in the entire village who would look down on him.
Although his formidable strength looked simple enough on the surface, just how many people could actually persevere through such intense conditioning?
"Who's to say otherwise? But things like this shouldn't be our concern. The Uchiha clan is holding their clan meeting tomorrow, and this time is crucial for us. Those bastards really seem to be starting a rebellion, so we'd better hurry up and do what we need to do!"
A man wearing a fox mask muttered these words to the person beside him before the group instantly vanished into the woods.
……
"Ah, this is so comfortable!"
Under the cover of night, Uchiha Kai lay atop a massive boulder, gazing up at the starry sky and listening to the sound of flowing water nearby. Everything felt quite serene to him.
Sprawled out in a star shape on the giant rock, he kept his wide eyes open, feeling the breeze sweep across his body and listening to the rush of the river flowing down below the cliffside.
The exhaustion from the daytime seemed to vanish in an instant.
"Nine years already! And only two years left until that incident... Two years?"
Suddenly thinking of something, Uchiha Kai sat straight up.
"Two years? The Uchiha clan is holding their clan meeting tomorrow—doesn't that mean that bastard might die today? And right here in this river area?"
Uchiha Kai suddenly recalled this detail, yet he wasn't certain at what time today this node in history would occur.
Nor was he sure at which exact spot along the Naka River it would take place.
Standing up, he peered forward along the river by the moonlight.
The area behind him belonged to the Uchiha clan, while the area ahead connected to Konohagakure's outer perimeter and ran straight through the Forest of Death.
This meant the possible range where it could happen wasn't all that large.
As for the Uchiha clan meeting, it had zero to do with him.
Those gatherings only summoned Chunin-rank members and above.
After all, Genin and ordinary people from the civilian districts weren't even given a second glance.
"Shadow Clone Technique!"
Having confirmed his goal and direction, Kai instantly summoned a clone. The moment the clone materialized, it transformed into a raven and other birds.
They began to station themselves at regular intervals along both banks of the river.
"The ultimate evolution of the Byakugan requires gathering all the eyes together, which means extracting the pupil power from every single eye. So what would happen if you gathered the pupil power of every single Sharingan together?"
Having completed those preparations, Uchiha Kai now just needed to quietly wait for the big fish to take the bait; there was no need to stare fixedly at the spot the entire time.
He lay back down, plotting how he could manage to acquire some Sharingans when the Uchiha clan massacre occurred two years later.
As for scattering his Shadow Clones, the reason he cared so much was that the original plot had begun to shift slightly, and reality held something that terrified him.
Uchiha Shisui's Mangekyou!
Kotoamatsukami!