Shirakumaru was the second test subject for Satsuki's Infinite Control: Eight Gates Human Puppet technique.
Originally the vice-captain of the Iga castle lord's personal guard, he was a male around twenty years old. Judging by his chakra levels, he was roughly on the level of a jonin, though not particularly outstanding among that class.
But for Satsuki, he was already a rare and valuable specimen. The other materials in her possession had various other uses and couldn't be converted into puppets as freely.
After a simple evaluation, she discovered Shirakumaru only possessed a single lightning chakra nature—nothing remarkable.
Through genjutsu interrogation, she extracted all knowledge of his ninjutsu repertoire before erasing his consciousness.
As her second test subject, Satsuki naturally learned from the cruder control methods she had shown to the system before. Under the enhanced clarity of her Byakugan, she began semi-experimental, semi-practical training with this body in the use of the Eight Gates.
Extreme and overloaded training was ideal for a human puppet with no consciousness remaining.
Moreover, her puppet technique relied entirely on chakra manipulation, so there was no need to hollow out organs or apply preservation measures. This preserved the body's potential for further strengthening.
Though only five days had passed, there was no way Shirakumaru could open all Eight Gates, even with training. However, his body already had a solid taijutsu foundation and lightning release stimulation methods, allowing for faster progress than most.
At present, he was the only puppet Satsuki could deploy as a fully combat-capable jonin-level force.
Her other samurai puppets were no match for a true jonin.
As for Satsuki herself, her schedule was packed with ongoing research and her upcoming meeting with the Senju clan, so she didn't have time to personally visit Valley of Clouds and Lightning.
...
In the forest—
Shirakumaru, clad in a white cloak, darted between the trees. An image of a hawk was printed on his mask, and a tomoe symbol adorned the back of his cloak. Flickers of visible lightning danced across his body.
Each time lightning surged, his muscles subtly adjusted and trembled, gradually adapting to the stimulus. Specific chakra points were slowly loosening, reducing the internal restrictions on chakra flow.
This process demanded extraordinarily precise chakra control and was excruciatingly painful. Any slip could cause cardiac arrest.
Even for a puppet whose consciousness had been wiped, achieving a permanent opening of the first three gates would still take months.
But this pace would be considered terrifying for a normal shinobi.
While Satsuki controlled Shirakumaru, her focus was abruptly interrupted by the appearance of three unfamiliar chakra signatures.
According to the Byakugan's readout, they were heading directly toward her location.
Initially, Satsuki wasn't interested in provoking unnecessary trouble. She casually altered Shirakumaru's route several times. If they were simply passing by, nothing more would happen.
But after a few minutes of travel and synchronized changes in the pursuers' direction, she began to frown.
Despite running other experiments in parallel, she had left enough attention free to handle the puppet.
The pursuers' continued mirroring of her movements confirmed their hostile intent.
In this era, it was basic etiquette among strangers to keep a safe distance. Even someone like Uchiha Madara couldn't stand people sneaking up behind him. It was an unspoken survival rule of this chaotic age.
Eventually, the long chase wore the pursuers' patience thin. With a burst of speed, the trio flanked and outmaneuvered Shirakumaru, setting an ambush ahead.
To preserve chakra for emergencies, Satsuki had not kept Shirakumaru in a constant state of high-speed movement.
Though Satsuki still lacked the ability to control puppets over ultra-long distances, taking out these few pursuers was more than within her means.
Just as Shirakumaru was about to enter their ambush—his right hand rose and swept through the surging air around him. A dozen senbon made of lightning chakra launched with piercing force, tearing through massive tree trunks and striking directly at the ambushers concealed behind them.
Realizing their movements had been discovered through prior directional changes, the three enemies dropped all pretense. Using swift Body Flicker techniques, they emerged and confronted Shirakumaru head-on.
The leader, fastest among them, swung his bandaged right hand in midair.
Whoosh~ Whoosh~ Whoosh~
Three kunai cut through the wind with a sharp whistling sound.
One of his companions held a hand seal, with his shadow already extending into the forest shadows below. The last began forming seals for a jutsu.
"Wind Release: Great Breakthrough."
This wasn't a particularly sophisticated tactic, but it was practical. Their teamwork showed they were well-trained and not new to collaboration.
But Shirakumaru was unlike any opponent they'd faced.
With the power of Satsuki's Byakugan guiding him, he had perfect clarity over the battlefield.
With a flick of his own kunai, he deflected all three incoming projectiles with ease. At the same time, his body surged with lightning and accelerated dramatically, dodging the wind blade that followed.
Just as he was about to counterattack, a strong binding force suddenly locked him in place.
Shadow Possession Jutsu?
Impressive.
He silently praised the enemy's foresight. They had anticipated his escape route and positioned themselves accordingly.
"Kill him now! His chakra and taijutsu are too strong—I can't hold him much longer!"
The long ponytailed ninja shouted from a distance, sweat pouring down his face from the sheer effort it took to restrain Shirakumaru.
Responding quickly, the kunai-throwing ninja drew a blade from his back and lunged forward like a tiger pouncing from its cage.
"Good combat sense... Nara Clan, huh?"
Unfazed, Shirakumaru opened the First Gate of the Eight Gates under Satsuki's control, releasing the brain's limiter.
With that, he lifted one hand—completely ignoring the binding effect of the Shadow Imitation Technique—and pointed straight at the oncoming attacker.
Psshht~
A thin, piercing lightning spear formed and instantly pierced through the ninja's heart.
"Impossible," muttered the Nara clan member, overwhelmed, "He broke free from our clan's secret technique so easily... What the hell is going on?"
When protagonists say that line, a villain often explains everything. But when background characters say it, it usually means death is imminent.
Another Shirakumaru silently emerged behind the Nara ninja. Before he could react, a clean slash took him down. Even as he died, he still tenaciously maintained the Shadow Possession.
"Was that just a clone we fought earlier?"
The last surviving ninja was drenched in cold sweat.
"Which one is real... which one is fake?"
His mind raced with possibilities. In a moment of clarity, he decided that the version that had just slain his leader must be the real one—there was no other way to explain how it had broken free and used such powerful chakra manipulation.
He rushed at the still-standing, arm-extended Shirakumaru.
He drove his kunai into the puppet's body.
"Did I... guess right?"
Before he could revel in a narrow escape—
A mocking smile curled across Shirakumaru's face.
From beneath his cloak, three active explosive tags glowed ominously.
"Unfortunately, you guessed wrong."
Boom!
With a deafening explosion, the three attackers were annihilated on the spot.