Takuno's inner desire to transplant the Hashirama cells was incredibly intense, but he suppressed this urge with his powerful willpower and did not put it into action immediately.
He knew deep down that now was by no means the best timing, because having just unleashed the "Perfect Susanoo," his own chakra and physical condition had not yet recovered to their peak levels.
Furthermore, the transplantation of Hashirama cells was absolutely no ordinary surgery; the massive risks it harbored were enough to make anyone stop in their tracks.
The lessons from the original work stood right before his eyes.
Konoha had initiated a Hashirama cell transplantation project during past times of crisis and recruited volunteers to participate in the experiments; however, the result was a complete disaster—not a single participating ninja escaped unscathed, all perishing during the trials.
Even later, in the much larger-scale subsequent research led by Orochimaru and Danzō where countless experimental subjects were thrown in, only Yamato miraculously survived in the end and successfully mastered the Wood Release Kekkei Genkai.
More crucially, Yamato's survival could be said to be an extremely accidental event; even the genius scientist leading the research, Orochimaru, could not replicate this result, and at that time, he hadn't even learned about the fact of Yamato's survival in a timely manner.
To this day, even with Orochimaru's technological capabilities, there was no guarantee that he could use Hashirama cells to successfully cultivate another "Yamato."
These bloody cases collectively pointed to an irrefutable fact: fusing Hashirama cells was an experiment with an extremely high risk of death.
With even a slight oversight, the powerful Hashirama cells would backlash against the host, completely eroding and swallowing the fresh living body, ultimately turning it into a lifeless wooden statue heading toward death.
Among the known successful cases, aside from Yamato, the others who could withstand Hashirama cells were almost all inextricably linked to possessing the unique ocular technique "Sharingan" or having a profound connection to the power of the Divine Tree.
Although Takuno had already awakened the Mangekyō Sharingan, which could provide him with sufficient protection, he absolutely dared not show the slightest negligence or let his guard down because of it.
What he needed to do was prepare in the most flawless posture possible, lowering the potential risks to the absolute minimum within the scope of his capabilities!
...
Several days of time quietly slipped away amidst dedicated training and recovering his condition.
Takuno sat cross-legged quietly upon his bed with his eyes tightly shut, his entire body enveloped in a profound aura.
As his understanding of Sage Mode grew increasingly deep, his posture also drew closer and closer to that of the legendary Sage of the Six Paths.
At this moment, his iconic purple eyeshadow was gradually fading at a speed visible to the naked eye, ultimately receding completely into his eyelids.
Takuno slowly opened his eyes, a sharp glint flashing and vanishing within them as he completely exited Sage Mode.
This was not because he lacked the strength to maintain it, but because the crucial experiment he was about to conduct next would tolerate not a single shred of distraction.
He stretched his muscles and bones, feeling the torrential power surging within his body.
Abundant physical strength interwoven with a full spiritual state was precisely the perfect condition to launch that important experiment.
Moving his steps to his exclusive laboratory, Takuno's gaze focused on the specially crafted growth container before him.
Quietly contained inside was precisely the precious sample he had obtained from Danzō's secret base, the "Root" base: the cells of the First Hokage, Hashirama.
Back then, the amount of the initial sample he obtained was not considered large.
However, after so many years of careful *Cultiv* and proliferation, the quantity of these cells harboring powerful vitality had now reached an inexhaustible level.
At this time, Takuno formed hand seals with both hands, and a Shadow Clone appeared by his side, taking out a portion of the Hashirama cells along with a syringe.
Takuno himself found a suitable position and sat down; the Shadow Clone did not hesitate either, injecting the Hashirama cells into Takuno's body.
The moment Hashirama's cells, which contained torrential vitality, entered Takuno's body, a sensation of rejection originating from biological instinct swept over him like a surging wave.
The moment these outsiders entered his bloodline domain, they immediately revealed their domineering and peerless nature.
They displayed a shocking aggressiveness, beginning to frantically swallow Takuno's own original cell tissue.
That swallowing force was so turbulent and magnificent that even amidst the violent physiological reactions, Takuno could not help but secretly marvel.
"As expected of the cells of Hashirama, who was hailed as the 'God of Shinobi'; this vitality and aggressiveness are indeed terrifying!"
However, to his surprise, the situation was not as helpless as imagined.
Even before he deployed the Yin Release power of the Mangekyō Sharingan to intervene, he discovered that his main body's cells, when facing the fierce onslaught of the Hashirama cells, actually displayed an extraordinary resistance.
They were not instantly swallowed without any ability to fight back; instead, they tenaciously resisted the erosion of the invaders.
This unexpected resilience caused Takuno's heart to stir slightly, and after a brief thought, he roughly deduced the reason.
This was likely credited to the fact that he had long ago forcefully fused the resilient vitality of the Uzumaki clan, the pure bloodline ocular power of the Uchiha clan, and the Wood Release bloodline into one through the forbidden jutsu Chimera Technique.
The vitality foundation of the Uzumaki bloodline was deep, and the tier of the Uchiha bloodline was similarly extraordinary.
And most crucially, within that portion of the Wood Release bloodline he had absorbed, the precious experience of successfully fusing Hashirama cells was inherently inscribed.
The stacking of these factors made his body's natural resistance to Hashirama cells far more powerful than he had previously estimated.
Despite this, Takuno clearly perceived that relying solely on this resistance for passive defense might allow him to endure longer than ordinary people, but the final outcome seemed already predestined.
He would eventually be completely swallowed by this powerful external life force, reduced to a lifeless wooden sculpture.
But this layer of realization did not bring despair; instead, it stimulated a new train of thought.
Since his basic resistance was solid enough, then the power of the Mangekyō Sharingan would no longer merely be a tool for brute-force suppression.
He could perhaps walk a path of fusion that was closer to the core essence.
He discarded the crude plan of mimicking Madara's method of relying on powerful ocular power to forcefully suppress the Hashirama cells.
Although that method was effective, the price was massive; it would inevitably leave indelible "traces" on the body, such as the face of Hashirama on Madara's chest or Danzō's pale, deformed arm.
He turned his gaze toward another successful case: Yamato.
However, the amount of Hashirama cells Yamato fused was minuscule, and restricted by his own weak physique, he simply could not carry more.
Yet, he succeeded, and with almost no side effects!
Takuno's situation was entirely different from Yamato's!
Not only did he possess a basic resistance far exceeding ordinary people, but he also had the Mangekyō Sharingan—a sharp enough "scalpel"—providing powerful Yin Release power for fine-tuning and suppression.
This meant he possessed a unique and blessed advantage.
He did not need to forcefully suppress the Hashirama cells into his chest area like Madara did; instead, he could perform a deeper level of fusion.
Takuno still possessed a great deal of experience regarding fusion.
After all, his signature forbidden jutsu, the Chimera Technique, involved a massive number of fusion schemes.
If this method could succeed, then what he possessed would not be Hashirama's Hashirama cells, but... his own 'Hashirama cells.'
At that time, the cell activity would increase, and his chakra reserves would also be able to achieve a qualitative leap!
Of course, wanting to directly reach Hashirama's chakra volume remained an impossible thing.
Takuno took a deep breath, and then opened his eyes; after instructing his Shadow Clone about a few matters, he began his attempt at fusion.
At this moment, all of his spirit was focused on that cluster of restless power inside his body: the Hashirama cells.
Attempting fusion was the mandatory path to a stronger realm, yet it was also fraught with extreme danger.
He could not even utilize the Spirit Transformation Jutsu to experiment on someone else's body beforehand.
It was not that he was unwilling, but rather that he couldn't.
Other people's body structures, cell activities, and chakra characteristics, compared to Takuno's own heavily tempered body, differed like a natural chasm.
Rashly attempting it would not only yield results of absolutely no reference value, but would more likely waste his energy for nothing.
However, Takuno was not without options.
His pair of Mangekyō Sharingan, which contained powerful Yin Release, was currently the most precise control instrument.
A clear plan formed in his mind.
Using the ocular power of the Mangekyō as a boundary, he would firmly suppress the activity of the Hashirama cells within a specific, non-lethal muscle tissue.
The corners of Takuno's mouth tightened into a straight line.
Although his method was not without cost, it reduced the risk to the limit of controllability.
Attempting fusion within a restricted zone.
If successful, he could use this as a blueprint to guide this newly born power to expand in an orderly manner to every single cell across his entire body, completing a thorough metamorphosis.
If it failed... the ocular power of the Mangekyō would be the sharpest scalpel, sufficient to instantly and precisely isolate and excise the cell tissue of the experimental zone.
Exchanging the loss of a partial tissue for the safety of the entire body.
Being able to apply this level of methodology to fusing Hashirama cells was perhaps something that only he could achieve.
Recalling when Madara fused Hashirama cells back then, he must have been struggling to survive amidst a desperate situation of life and death; how could he have the luxury like Takuno to meticulously plan and experiment region by region?
He could only place a single desperate bet, gambling his entire future on a completely unknown result.
And once this plan succeeded... a burning light flashed in Takuno's eyes.
His basic strength would once again undergo a complete metamorphosis.
For someone like him who already stood at the pinnacle of the Shinobi World, every single leap in strength could be called a miracle.
This was not merely the stacking of power, but the evolution of the biological tier of life itself.
Just imagine, already situated upon the absolute summit of power, yet still capable of maintaining such a terrifying rate of improvement!
...
Inside the laboratory, time seemed to be stretched into something viscous and long.
Takuno was engaging in a unique contest against time and against the Hashirama cells, fusing and assimilating those Hashirama cells that contained terrifying power.
This was by no means simple containment, but a battle of conquest where only one side would walk out alive.
Hashirama cells were notorious for their violent vitality and near-greedy aggressiveness; they frantically wanted to backlash and swallow the host's cells.
Takuno's goal, however, was to swim against the current, completing the assimilation of this "ferocious beast" and turning its power to his own use.
This path was far more difficult than simply fusing them and then using the Mangekyō Sharingan to suppress them inside the body.
Takuno's spirit was highly concentrated as he carefully guided the energy, attempting to construct that nearly impossible-to-achieve balance.
Day after day, the duration of the continuous experiment was long enough to cause any onlooker to feel despair.
However, Takuno's gaze remained as sharp as an eagle's throughout.
After countless failures, and within a wait long enough to obliterate an ordinary person's willpower, he finally captured a spark sufficient to start a prairie fire—a single cell!
Yes, merely a single cell belonging to his own body successfully reversed the situation and completed the thorough assimilation of a Hashirama cell!
Compared to the vast sea of tens of trillions of cells inside a human body, this single successful survivor was as tiny as a grain of sand in a desert.
But this "grain of sand" weighed heavier than a mountain!
Takuno's long-dormant heart violently contracted, and was subsequently swept over by immense ecstasy and exhilaration.
This was by no means an insignificant progress; this was a earth-shattering leap from zero to one!
Of all things in the world, nothing was harder than pioneering from nothing to something.
The success of this cell was not only an isolated point, but it illuminated the coordinates of the entire road, proving that the path leading toward victory truly existed!
An even more astonishing chain reaction followed immediately.
That successfully assimilated cell, and the specific area it was located in, seemed to instantly obtain the core decryption key to the Hashirama cells.
An efficient "assimilation solution," at a jaw-dropping speed, expanded exponentially!
The conquest at the cellular level began its frantic replication and spreading.
"It's working!" Takuno shouted silently in his heart, an indescribable excitement surging within his chest cavity.
All the effort put in over such a long period of time seemed to receive an answer at this moment.
However, this excitement did not collapse his rationality.
He was not blinded by the initial victory, and he certainly did not rashly untie all the restricted zones holding back the cells.
He adopted a more stable strategy.
Tentatively lifting the restrictions on a portion of the regions.
His nerves were highly taut, every sense magnified to the extreme, ready at any second to respond to any potential backlash.
Fortunately, no accidents occurred; the other regions that had their restrictions lifted perfectly followed this "correct path" as well, their assimilation speeds being equally swift.
Yet Takuno still suppressed the urge to completely liberate everything.
What was currently displayed was merely success at the relatively simple, non-core cellular level.
The true test lay in those vital organs that maintained the foundation of life and possessed precise structures: the internal organs!
Aside from the heart acting as the core engine, the liver, the kidneys, the lungs... a failure in the fusion of any single organ would be enough to cause an unrecoverable price.
Even if they could be replaced later, how could a replaced one be as useful as his own original?
As for the most crucial and most fragile heart and brain, they were viewed by him as the final fortresses, left at the very end of the sequence for final storming.
His experimental plan was clear and rigorous.
Proceeding from the simple to the difficult, from the outside to the inside, with the importance progressing layer by layer.
The success of every single step was laying the foundation stone for the next step.
Now, he had already stood at the starting point of success, looking toward a direction one step further ahead!