As a transmigrator, Uchiha Yue was naturally no stranger to the concept of absorbing and refining the spiritual energy of heaven and earth, cultivating the path to immortality and eternal life.
In the shinobi world of Naruto, although the mainstream cultivation system revolves around Chakra, the essence of Sage Mode lies in harnessing natural energy—a force that closely resembles the so-called "spiritual energy of heaven and earth" from Chinese cultivation lore.
Moreover, many figures titled "Sages" in this world indeed boast incredibly extended lifespans—ones that far exceed the natural longevity of their species, such as the Great Toad Sage and the White Snake Sage. This leads Uchiha Yue to reasonably suspect that what is referred to here as "natural energy" may in fact be the same substance as the spiritual energy in other cultivation systems, only named differently across dimensions.
Thus, if one could completely absorb and refine this energy without relying on the intermediary of Chakra, the physical body would logically evolve in turn, resulting in a drastic increase in strength, vitality, and potentially lifespan.
"There should be no mistake—thoroughly refining natural energy should directly increase life expectancy," he thought.
"But what a pity… this world, after all, belongs to the shinobi system—it is the world of Chakra. Even something as extraordinary as Sage Mode cannot escape its limitations, as it still operates through the framework of Chakra refinement."
"Moreover, the nature of natural energy is incredibly volatile. Only a few individuals—those with unique bodily constitutions or exceptional talent, like Jiraiya, Naruto, or Kabuto—can sense and utilize it safely. Most ninja can't even begin the process."
"Worse, those who do achieve Sage Mode often treat it as a last-resort trump card—a temporary power-up—rather than a foundation for a long-term path to true immortality. So no one ever truly walked the road to transcendence."
"Instead, that potential was seized and weaponized by summoned creatures and holy lands like Mount Myōboku, Ryūchi Cave, and Shikkotsu Forest, who granted power in exchange for obedience. So-called 'Sages' became their vessels."
Carefully observing the ebbing flow of Chakra within his body and the faint transformation triggered by the assimilation of a trace amount of natural energy, Uchiha Yue couldn't help but sigh inwardly. The shinobi of this world, in his view, were shortsighted and pitiful.
"Forget it! Since no one else in the ninja world has taken this path, I'll be the one to develop a true immortal cultivation technique! After all, who wouldn't long for genuine immortality?"
Shaking his head and pulling himself back from his wandering thoughts, Uchiha Yue returned his focus to the internal changes unfolding in his body. A conviction grew clearer in his mind.
As a traveler from modern-day China, he naturally held a deep fascination for concepts like immortal cultivation and longevity. Now, with Sage Mode within reach—albeit in its incomplete form—he had finally stepped into that territory.
"Unfortunately, although this world contains the foundation for cultivating immortality, it never developed into a formal Immortal Path. There are no systems or manuals for cultivation techniques. If I want to recreate the immortal arts I remember, the time and effort required would be astronomical."
"Therefore, the top priority for now is still cultivating Chakra."
"Besides, if the Chakra system is developed to its pinnacle—such as the path walked by Ōtsutsuki Kaguya, who consumed the Chakra Fruit and awakened a god-like bloodline—even that leads to immortality and overwhelming power."
Though still full of longing for true immortal cultivation, Uchiha Yue quickly adjusted his mindset and turned his attention back to the known Chakra system.
After all, developing a completely new Immortal Path isn't something that can be accomplished overnight. It would require extensive research, theoretical deduction, and countless trials.
In contrast, the Chakra system is already mature. With the illusory world he created, his specially evolved Mangekyō ability, and a deep understanding of many Chakra secrets, he only needed to continue devouring and fusing carefully to eventually stand at the summit.
Rather than scatter his focus prematurely, it was better to reach the peak through Chakra first—and then reverse-engineer immortality from that high vantage point. Through analogy and synthesis, not only could his strength grow faster, but his research into immortality could also yield far more fruitful results.
Moreover, despite his current power, he had not forgotten the lurking presence of Hagoromo Ōtsutsuki—the Sage of Six Paths. That ancient entity was undoubtedly watching the world from the shadows.
If his rise one day drew the ire of that ancient force, and he lacked the means to defend himself, the consequences would be catastrophic. He could not afford to be caught unprepared in that pivotal moment.
"Well then… since I've already fully devoured and fused Jūgo's cells, it's time for Kimimaro. I wonder how much of a leap forward I'll gain from this next fusion."
Suppressing his swirling thoughts once again, Uchiha Yue looked at Kimimaro's cells, muttered softly to himself, and began the devouring and fusion process anew.
Time flowed quickly.
Relying on the power of the illusory world, it came as no surprise that Uchiha Yue flawlessly completed the devouring and successfully awakened the Shikotsumyaku (Dead Bone Pulse).
"Hmm… this sensation… every bone in my body feels responsive, obeying my thoughts perfectly. I can shape them however I wish."
Re-solidifying his body from the illusory realm and sensing the unfamiliar strength now embedded within him, Uchiha Yue silently evaluated the transformation. Then, extending his index finger, he guided Chakra through it instinctively.
Crack.
A sharp sound, like grinding bone, echoed softly. A glistening, jade-colored bone spear extended smoothly from his fingertip—otherworldly in appearance.
"This is… my bone? That jade-like shine—could this be the legendary 'ice-muscle jade-bone' described in immortal cultivation texts?"
"And this terrifying durability—it's no weaker than the elite Chakra-forged ninja tools I seized from Danzo's vault!"
Examining the bone intently and casually stabbing it into the earth, Uchiha Yue couldn't hide the amazement in his eyes. He couldn't help but marvel aloud.
He knew well that most of the elite ninja tools stored by Danzo were crafted from Chakra-conductive metals—rare, high-grade materials with extraordinary hardness and cutting power.
Now, the strength of his bones—just by existing in his body—meant a natural defense surpassing most common weapons. And when used offensively, their destructive potential was equally formidable.
"Excellent. Not only have my bones become stronger, but my physical strength has also seen significant growth. I can now say with confidence that my raw physical attributes have reached the Kage level."
"If not for some remaining gaps in full-body defense, I might even stand toe-to-toe with the Third Raikage based on pure physical prowess."
Letting the bone shard fall to the ground, Uchiha Yue contemplated the overall enhancement in his physique. The image of the indomitable Third Raikage—the man reputed to have battled 10,000 enemies alone—surfaced in his mind.
After all, with both Sage Body and White Zetsu cells already merged into his system, and now the addition of Kimimaro's Shikotsumyaku, Uchiha Yue's physical form had become a fortress.
In this world, where most Jōnin possessed relatively fragile constitutions, only outliers like the Third Raikage, who had tempered their bodies to near-divine levels, were worthy comparisons.
By contrast, even the Fourth Raikage, known for his speed and strength, was already falling behind Uchiha Yue at this stage.
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