A dark underground space.
Clang! Clang!
"Not enough, not enough, not enough.
As a Ninja, your actions must not be predictable to others; you must feint.
The more you consider, the higher your chances of survival."
Orochimaru spat out a blade, which clashed with Sasuke's kusanagi blade, eventually resting the blade against Sasuke's neck.
Sasuke was more mature now, no longer the naive boy he once was, already developing into an adult.
He showed no pleasant expression in response to Orochimaru's words.
But he would learn everything Orochimaru said.
"Again," Sasuke said impatiently.
His current strength was too weak; even with the Cursed Seal activated, he was powerless against Orochimaru.
"Heh heh heh, very good.
I hope you don't disappoint my training, otherwise, it will be very difficult for me to kill Itachi and avenge your Uchiha clansmen!" Orochimaru retracted the blade in his hand, laughing with his tongue out.
"You don't need to tell me, I will kill that man with my own hands." Sasuke clenched his fists.
"You're still far from it.
It's not just a matter of combat experience.
Your Sharingan development is too far behind your brother's.
I hope that in a year and a half, you'll be a satisfactory body.
You are still far from developing your full potential."
Although Sasuke's combat experience was already very strong, and he even performed many actions that surprised Orochimaru.
However, for a Ninja like Orochimaru, his actions were still too obvious.
Upon hearing this, Sasuke clenched his fists even tighter.
He was confident in the power of his Sharingan, but facing strong individuals like Satoru and Orochimaru, he always felt that his Sharingan was still lacking something.
"Don't worry, since I said I would give you power that surpasses Itachi, I will absolutely make you surpass him.
I am not an old fossil like the Third Hokage, always taking the conventional path.
I will use various methods to strengthen your power until..."
"Until my body becomes yours, right?
Don't worry, if you can do that, I don't care who kills Itachi." Sasuke said expressionlessly.
"Heh heh, let's go, follow me." Orochimaru flicked his tongue and turned to walk in one direction.
"Continue training." Sasuke didn't want to waste training time and spoke in a commanding tone.
"Heh heh, I also want to continue training, but guess what I found on you.
Perhaps Konoha's people will appear at my base tomorrow." Orochimaru paused his steps, turning back with a sinister expression.
His snake-like eyes were particularly captivating.
"Hm? Did Konoha's people do something to me?" Upon hearing this, Sasuke frowned.
Was it Kakashi-sensei?
Naruto?
Or someone else?
He thought a lot but didn't realize when something had been planted on him.
From Orochimaru's words, it seemed someone had planted a tracking device in his body.
Could it be Itachi?
He recalled the information on the stone tablet found in the secret chamber deep beneath the Uchiha clan's land.
Was it to pinpoint my location, to find me when I obtain that power?
But Orochimaru also said that Konoha's people might come.
Orochimaru: "I'm afraid so.
What an exceptionally brilliant young man.
To be able to develop such a Ninjutsu is truly amazing!
If only he weren't from Konoha and hadn't been brainwashed by the Third Hokage's will of fire, I would really want to cooperate with him!"
He thought of what he had discovered and found the matter very interesting.
He had only found it after studying Sasuke's body for over a year.
With this ability, no wonder he was sent to pursue the rogue Ninja Itachi back then.
Sasuke followed behind Orochimaru.
Tap, tap, tap!
In the deep tunnel, the footsteps gradually slowed.
Arriving at a large door, Orochimaru opened it.
Kabuto's figure appeared before the two.
He held a test tube, gently shaking it.
As it shook, a tree-branch-like pattern moved with the liquid in the tube.
It was like a tree root falling into the ocean and swaying in the deep sea.
Hearing the door open, Kabuto gently put down the test tube and turned his eyes towards the door.
"Lord Orochimaru, you've arrived."
"Kabuto, how is it? Any other discoveries?" Orochimaru asked.
Sasuke also fixed his gaze on the test tube.
Looking at the tree-branch-like pattern on it, he frowned slightly.
This was what was taken from his body?
Sharingan!
His eyes gradually turned into a three-tomoe Sharingan, and the Chakra flow within the tree-branch-like pattern in the test tube appeared in his sight.
Moreover, it absorbed the energy of the liquid in the test tube to maintain the pattern's continuity.
It was as if it possessed life.
"What is this?"
Kabuto explained: "This is a human nerve, which has undergone a powerful Yin-release nature transformation, allowing for neural refinement and extension.
It can move within living organisms and objects, and can absorb the host's physical energy, mental energy, or Chakra to sustain itself.
It should be some kind of secret Ninjutsu that separated the nerve and utilized this characteristic to embed it within your body."
Sasuke's brows furrowed even tighter upon hearing this.
When, and who, planted it on him?
No wonder Orochimaru said that Konoha's people might arrive the next day.
This ability was probably not Itachi's.
If Orochimaru hadn't discovered it, did that mean his own life was always in someone else's hands?
"What about other aspects?" Orochimaru asked.
Kabuto: "Hmm, I have already performed secondary cultivation and cutting, and used this part for experiments.
As you suspected, Lord Orochimaru, if this nerve is combined with a certain secret Ninjutsu, it can connect with the person's body after being planted, thereby disrupting their nervous system and causing their body to lose control."
Saying this, he glanced at Sasuke.
"Secondly, this ability should also be usable with Genjutsu.
As long as this nerve remains within a living being, that being cannot avoid Genjutsu through normal means, meaning they will be 100% afflicted by Genjutsu."
He said, looking at Sasuke with pity.
"Thirdly, and what Lord Orochimaru found most interesting, has also been confirmed through experiments.
This neural secret Ninjutsu can also steal information from inside a human body (or object).
This means that things like Taijutsu, Ninjutsu, secret Ninjutsu, etc., if he wishes, everything is probably under his control."
At this point, Kabuto's tone was already filled with incredulity.
And much exclamation.
Orochimaru had said that Sasuke had something like this on him and suggested many possibilities, but even after he experimented, he still thought it impossible.
But as the experiments progressed, this seemingly very ordinary human nerve could do so many things.
He looked at Sasuke with even more pity.
"Will the person who created this secret Ninjutsu not discover it?" Orochimaru asked.
Kabuto pushed up his glasses: "From the nature transformation revealed by this nerve, it seems that to steal human information, it would likely need to be within the Ninja's sensory range.
That is to say, for now, the only thing this nerve can do is probably tracking..."