It was just that this plan had been shelved for a long time.
It was not a lack of ideas, but rather being limited by conditions that made it impossible to implement.
He had not failed to try designing relevant Jutsu.
The biggest obstacle lay in the level of application.
Unlike those "Attribute Sealing" Jutsu engraved on the surface of a panel that also acted on the surface of the body, a Jutsu to enhance nerve reflexes must act directly on the neural network itself.
If it were merely engraved on the body surface, these rune nodes would be extremely susceptible to impact or chakra interference during intense combat.
Once the structural balance of the Jutsu is destroyed, it would be ineffective at best, or at worst, cause internal chakra disorder, and even inflict unpredictable damage to the sensitive nervous system.
Although Takuno could recover from any such damage with his current physique, he would inevitably be in the middle of battle when encountering such things, and there would be no time left for him to recover.
Therefore, in Takuno's view, doing so was not a strengthening, but rather creating a fatal weakness for himself, which was completely meaningless.
But now, the situation was different.
A brand new solution was gradually becoming clear in his mind.
Perhaps... he had finally found a way to safely engrave the nerve reflex enhancement Jutsu and make it almost immune to external factors during combat.
And the key to Takuno achieving increased nerve reflex speed did not rely on the Tenseigan, but on utilizing the unique Kekkei Genkai of Shikotsumyaku.
The ability that Shikotsumyaku grants its user goes far beyond merely manipulating bones for simple offense and defense.
Its core lies in the ability to absolutely control the entire skeletal structure, generating, decomposing, and precisely manipulating every bone at will.
This means that any operation related to "bone" is within the scope of its ability.
And precisely because of this.
After Takuno extracted his vital spine from his body, he would not be paralyzed or lose body support, because he could regenerate a spine to temporarily support him where he extracted it.
It can be said that under the maintenance of Shikotsumyaku, as long as his chakra is not exhausted, his skeletal structure can always resist external interference and maintain the most perfect physical state.
It is this extraordinary control that solves the core problem of Jutsu engraving.
This "absolute stability" of bones provides the most ideal carrier for the Jutsu to enhance nerve reflex speed.
Takuno chose to engrave it directly at the core of the spine, which serves as the body's center.
Although this position isn't exactly impossible for everyone to destroy, but...
If someone could deliver an attack to the core position inside his body, wouldn't they be able to kill him directly without the trouble of destroying a Jutsu?
Therefore, the Jutsu engraved here is not like being engraved on a panel surface; there is basically no need to worry about anyone specifically destroying it.
Before this, Takuno lacked the Shikotsumyaku ability and could not directly manipulate bones.
He had thought about engraving the Jutsu on bones, but while he had the idea, he couldn't execute it.
After all, he couldn't just cut open all his flesh and blood to engrave a Jutsu, right?
Moreover, most importantly, bones themselves are not unchanging; although they change little, they still change over time.
By then, if he had painstakingly engraved the Jutsu on the bone, and suddenly it couldn't be used, wouldn't he have endured pain for absolutely no effect?
And after obtaining Shikotsumyaku, all obstacles were resolved:
He could precisely "take out" the target bone segment.
He could calmly generate a brand new bone inside his body to temporarily replace the one he took out.
Subsequently, he would precisely engrave the required nerve reflex enhancement Jutsu on the bone material he took out.
After the engraving was completed, he would decompose and absorb the newly generated bone and seamlessly "return" the engraved bone to its place.
More importantly, under the control of Shikotsumyaku, this bone engraved with the Jutsu would be completely unaffected by the human body's natural metabolic process, ensuring the long-term stability of the Jutsu's effect.
Therefore, with Shikotsumyaku, the conditions for implementing his nerve reflex speed enhancement plan were finally met.
This improvement in ability is of extraordinary significance to anyone.
It not only greatly improves his control precision and efficiency over his own complex Ninjutsu, but also allows him to seize the vital initiative in rapidly changing, intense battles, becoming a key advantage that determines victory or defeat!
Before long, the desk in front of Takuno was piled high with layers of scrolls, each one densely recording the embryonic form of the Sealing Jutsu he had just engraved.
These Jutsu structures were still in the most primitive, rough stage, inevitably full of numerous flaws and unsolved problems.
Energy node connections were unstable, chakra circuit efficiency was low, rune combinations had conflicts; problems were everywhere.
This situation was expected.
After all, although Takuno's ideas about this Jutsu had lingered in his mind for a long time, he had never put them into practice for in-depth research.
Therefore, although the work before him was not starting from scratch and had some foundation, the difficulty of wanting to truly take shape could not be underestimated.
However, what slightly surprised him was... the progress seemed much smoother than expected.
While Takuno continued to depict the Jutsu, his mind was also running at high speed.
He clearly felt that the whole process had a sense of smoothness, as if things were falling into place.
He knew that this was not because the Jutsu itself was simple, but because the height he was standing at now was different.
His profound accumulation in the past and his strength at the pinnacle allowed him to handle the current problems as if standing on a mountain peak, overlooking the maze below.
Those obstacles that seemed complex from below, when viewed from this high perspective, had their patterns and solutions become clear and distinguishable, and dealing with them felt exceptionally handy.
Takuno understood in his heart that if he had tried to create this Jutsu when his knowledge and strength were still shallow, the process would never have been as smooth as it was now.
Estimating with the current speed of progress, at most in a few days, a Jutsu framework that initially uses Lightning Attribute chakra to significantly accelerate the conduction speed of electrical signals in the body to enhance nerve reflex speed would be born in his hands!
Thinking of this, the attraction brought by the blueprint of success made Takuno completely intoxicated, his mind fully immersed in the world of constructing this Jutsu.
In the end, Takuno still failed to complete the initial construction framework of that new Jutsu within a few short days as expected.
This was not because his previous intuitive judgment was wrong.
It was precisely because as the days passed, a new situation took hold of him.
He noticed that his eyes began to have unusual sensations intermittently.
It was not severe pain, but a subtle stinging sensation hidden deep within the eyeball, or sometimes his vision would flash with an imperceptible blur without warning.
Although this discomfort was short-lived, it was enough to make Takuno pay attention.
After all, on one side was the Jutsu before him, which could still be studied in the future even if temporarily shelved;
On the other side was the Tenseigan, which was related to infinite potential and was in a critical evolutionary stage.
The relative importance of the two was self-evident.
Without any hesitation, Takuno made a decisive choice.
He immediately slowed down the rhythm of Jutsu construction and invested more energy and focus into nourishing and observing those eyes.
Consequently, the progress of Jutsu construction was naturally shelved, and the progress slowed down significantly.
A few days later.
Takuno sat cross-legged, his mind fully submerged in his body, focusing on feeling those eyes that seemed to have changed, the Byakugan.
An unprecedented sense of fullness pulsed at the bottom of his eyes.
Takuno could feel that his Byakugan had reached the stage when the original Toneri finally awakened the Tenseigan.
In other words, if he were to circulate his chakra into his eyes now, he could awaken his own Tenseigan!
However, Takuno could feel that the huge Golden Tenseigan had not stopped transmitting energy.
It was like an inexhaustible source of energy, still passing through that invisible bond, continuously injecting the extremely pure origin power of the Tenseigan into the depths of his pupils, strand by strand.
This power was still strengthening the foundation of his Ocular Power.
"Sure enough..." Takuno whispered, his thoughts drifting to the original Toneri, "Ōtsutsuki Toneri's eyes were forced to end their gestation at that time, and they probably dissipated back into Byakugan for this reason."
However, Toneri at that time had no choice but to end the gestation; after all, the Golden Tenseigan had been shattered by the combined efforts of Naruto and Hinata.
But at this moment, Takuno had no such problem at all.
So he chose to continue accepting this gift from the Golden Tenseigan, letting his own eyes complete the most perfect transformation and sublimation under the nourishment of the other party's power.
Even a more greedy thought sprouted in his heart.
Since that Golden Tenseigan now seemed to exist only for him... why not go further?
Why not try to completely absorb this vast and peerless power and make it his own?
"Draining the pond to catch the fish?" Takuno's mouth hooked into an arc, his heart calm, "Perhaps."
"But the key to the problem is... after me, who else in this world will use its power again?"
The answer was self-evident.
Since that was the case, even if he did that act of draining the pond to catch the fish, what of it?
Rather than letting this power rot in time, it was better to become the cornerstone for him to master stronger power!
Thus, Takuno began to absorb the power of the Golden Tenseigan without limit!
When Takuno was absorbing the power of the Golden Tenseigan, although the Jutsu aimed at improving nerve reflex speed was still in the deduction stage and not yet complete.
However, another ability into which he had poured countless efforts and time had now ushered in an unprecedented perfect transformation.
That was Sage Mode!
Yes, after long research and tempering.
At this moment, Takuno had achieved an astonishing feat: as long as his internal chakra was not exhausted, he could permanently maintain the state of Sage Mode!
And it didn't need to be specially maintained; even if he entered a real sleep state at this time, his body would automatically absorb Natural Energy to prepare the most perfect Senjutsu chakra!
This was the ultimate goal he had worked hard for a long time: the normalization of Sage Mode!
The arrival of this moment did not arouse pure ecstasy in Takuno's heart, but an indescribable, complex emotion.
After all, in order to master and finally achieve this normalized realm, he had spent several years of arduous research and attempts.
He even basically gave up real sleep time for this, turning it into a special stage of practicing Sage Mode.
However, if it weren't for assimilating Hashirama cells, which made his own bloodline quietly evolve towards a Sage Body, greatly accelerating this process.
Then achieving the feat of normalized Sage Mode would probably have taken even longer.
Of course, Takuno was very confident that even without the unexpected help of this Sage Body, relying on his own talent and perseverance, he would eventually be able to push open the door to normalized Sage Mode.
Because, at that time, he was already not far from normalized Sage Mode!
But it cannot be denied that the Sage Body paved a smooth path for him, turning the originally difficult climbing journey into a broad avenue, reducing the difficulty by more than a hundred times.
Being able to reach the finish line so quickly at this moment was certainly inseparable from his deep accumulation and paving over the years...
But Takuno also understood in his heart that even without those previous foundations, just by relying on the leap in physical potential brought about by the evolution of the Sage Body, trying to master normalized Sage Mode probably wouldn't take too long...
The huge difference here is like a junior high school student racking his brains to solve a junior high school problem, but suddenly being promoted to the high school level.
When he looked back at those "junior high school problems" that had troubled him, the stumbling blocks of the past instantly became surprisingly simple, even somewhat boring.
This feeling of being "dimensionally reduced" was the root of the mixed feelings in Takuno's heart at this moment.
Thinking of the road of exploration on which he had spent countless days and nights, it became so "easy" after his physique achieved a qualitative leap.
An indescribable mixture of relief after achieving the goal and a faint loss that the value of his efforts seemed to have been invisibly "diluted" quietly permeated his heart.
However, Takuno quickly adjusted his mindset.
In any case, the achievement of normalized Sage Mode was still enough to make people happy.
Takuno looked at the sky, the distant earth seemed to be glowing.
As things stood, his strength was getting stronger and stronger, and his subsequent tasks were gradually decreasing.
After all, at his level, the vast majority of things could no longer make his strength improve again.
Things that could make him improve again basically required Six Paths level items.
And the Six Paths level in this era... basically didn't exist.
At this time, Naruto was still more than two or three years away from graduating from the Shinobi Academy.
The time that originally felt a bit tight now seemed to have become more than enough!