After returning from the future timeline, Uchiha Kiyo came back to his island and did not venture out again. Even the procurement of daily living materials was handled through the Instant Body Technique.
Of course, part of the reason was cultivation, but more than that, it was actually Uchiha Kiyo's guilty conscience after witnessing the overwhelming strength of true super shadow-level beings.
Indeed, he once thought he was invincible, confident that he could at least contend with a super shadow-level opponent. However, reality taught him a harsh lesson—he was crushed even after preparing to unleash his strongest state.
During the final battle between Uchiha Madara and Senju Hashirama in the Valley of the End, each of their blows wrought devastating destruction. Even the "Gundam mode," Kiyo's fully empowered giant chakra armor, might not have been able to withstand those attacks.
This realization made Uchiha Kiyo acutely aware of his shortcomings.
If that was Madara's strength during his battle with Hashirama, then could Kiyo withstand Madara's full strength now? Uchiha Kiyo had no clear answer.
Even though he had improved considerably, reaching a higher realm of power, he was still unsure whether he could resist Uchiha Madara, who might have hidden many more trump cards.
It must be understood: Madara's capabilities were not limited to those seen during the future timeline.
If Madara could instantly transplant a massive amount of Hashirama's cells and temporarily suppress their erosion, he could theoretically return to his peak state for a period.
Considering Madara's monstrous willpower and control, it was beyond doubt that he could suppress the backlash from Hashirama's cells.
Although Kiyo himself had implanted some of Hashirama's cells into his body, the amount was limited. If Madara performed a massive-scale transplant, it was highly possible he would recover his former might. Uchiha Kiyo did not dare bet his life on resisting that possibility.
Thus, he chose to hide away.
Moreover, beyond Madara, there was another entity to fear—the Sage of Six Paths.
From his observations, Uchiha Kiyo sensed that some mysterious changes were taking place across the ninja world. Familiar characters from the original timeline were starting to behave differently, with noticeable changes in personality and style. In such an unpredictable environment, avoiding the Sage of Six Paths was a logical precaution.
Besides, life on the island was far from lonely for Uchiha Kiyo. Researching and developing the Immortal Cultivation System provided him endless satisfaction. Furthermore, during cultivation, he could feel himself constantly evolving—his body strengthening steadily—which brought immense joy.
Unlike standard ninja chakra training, which involved forcibly squeezing cells to refine chakra—a process that was both painful and left one feeling hollow—Uchiha Kiyo's self-created cultivation method was pure pleasure.
In the early stages, before his self-cultivation technique was perfected, Kiyo also had to endure the emptiness and discomfort of refining chakra. But now, after fully refining and perfecting the technique, he no longer needed to squeeze his cells. His entire cultivation process had become not only smooth but thoroughly enjoyable.
The sensation of energy nourishing and enhancing his body was profoundly refreshing—a joy that permeated his very soul.
---
Uchiha Kiyo himself did not leave the island, but he still needed to maintain his influence across the ninja world. Naturally, this responsibility fell upon his clones.
While his true body remained secluded, immersed in research and cultivation on the Island of Qing, his clones roamed the ninja world, conducting operations and managing long-term plans. Perhaps this was the ultimate use of the Clone Technique.
Considering Madara's secret schemes and the looming threat of the Sage of Six Paths, Kiyo's true body had to remain hidden. Thus, all external matters were handled through his avatars.
Sometimes, Uchiha Kiyo marveled at the foresight he had shown in developing his advanced clone techniques. Without them, carrying out his plans while maintaining secrecy would have been impossible.
---
Two years passed after Uchiha Kiyo established his Foundation Establishment stage cultivation. During this time, he further refined various techniques and even began planning his path beyond Foundation Establishment.
First and foremost, the physical forging realm remained crucial. After undergoing two bloodline eliminations, Kiyo's body forging realm had improved significantly.
However, after careful research and observation, Kiyo realized that calling his current state "late-stage body forging" was inaccurate.
The two improvements, while impressive, were still insufficient to meet his high expectations.
Upon completing his Foundation Establishment, Kiyo evaluated his strength. Preliminary analysis revealed that the Foundation Establishment stage corresponded to super shadow-level combat strength.
This division made sense: there had been no previous formal definition of super shadow-level power in the ninja world. Extremely few individuals ever reached that level, and in some eras, super shadow-level beings barely existed.
In earlier times, the Nine-Tails served as the unofficial standard—anyone capable of defeating or tying with the full Nine-Tails without using sealing techniques was considered super shadow-level.
However, that benchmark was problematic. Many powerful shinobi, like Tobirama Senju, had never battled the Nine-Tails, making it difficult to judge their true strength. Moreover, the strength of the Nine-Tails itself varied depending on the era—by Naruto's time, Kurama was often depicted in a weakened state (only half of its full chakra) and usually in cooperation with Naruto, further complicating assessment.
Thus, after establishing his Foundation, Uchiha Kiyo decided that the super shadow-level designation would align with cultivators who had just broken through Foundation Establishment—those who could wield chakra far denser and more potent than normal chakra through mastery of natural energy combined with spiritual energy, purely through basic Five Element jutsu.
Of course, this set only the threshold for super shadow level.
"According to this new classification, the entire Foundation Establishment stage corresponds to the super shadow level. Previously, the Qi Refining stage covered everything from Genin to Kage-level. It may seem imbalanced, but it matches the realities of power progression."
"Besides, the strength categorization in the ninja world was always vague. Apart from a few obvious bottlenecks, such as the leap to Kage-level, power levels were fluid, and there was no universally agreed realm division, especially in the earlier stages."
"And since no one else has established clear divisions, I, Uchiha Kiyo, will set the standards. These classifications are mainly for my own convenience, anyway. I don't intend to publicize Foundation Establishment yet."
Thus, the Foundation Establishment stage corresponded to the super shadow level, but there was still significant variation within the stage.
A newly established Foundation cultivator relying purely on elemental ninjutsu could barely reach the threshold of super shadow-level power. As one progressed, especially by supplementing with secret arts and forbidden techniques, the gap in strength could widen dramatically—similar to the difference between Madara and the Nine-Tails.
Uchiha Kiyo was satisfied with this division.
---
However, he was somewhat disappointed with the results of his two bloodline elimination upgrades. They had not pushed his body forging to the heights he had anticipated.
Thinking ahead, Kiyo speculated about the next major realm—the Six Paths level.
"After the super shadow level is the Six Paths level. Those at this level wield Truth-Seeking Balls, formed from Yin-Yang Release and the Five Elements. Does this mean the Bloodline Fusion corresponds to the realm after Foundation Establishment? Temporarily, I'll equate it to the Golden Core Realm."
---
But Kiyo immediately realized a flaw in this logic.
The Truth-Seeking Balls were the product of mastery over Yin-Yang and the Five Elements, but that did not necessarily mean they were equivalent to bloodline fusion.
Rather, they might be a byproduct or threshold for breakthrough.
"Maybe it's not that the Truth-Seeking Balls are rewards after the breakthrough to the Six Paths level, but mastering an equivalent ability is a prerequisite for reaching that realm."
In other words, the ability to create Truth-Seeking Balls—or an equivalent mastery of Yin-Yang and the Five Elements—might be a condition for breaking through to Six Paths power.
---
"Truth-Seeking Balls aren't bloodline limits. They seem more like a manifestation of the fusion of Yin-Yang and elemental chakra. Perhaps achieving perfect harmony among these forces leads to their creation."
Uchiha Kiyo understood that he couldn't figure it all out simply by theorizing. He would have to continue experimenting.
Since the enhancement from bloodline elimination wasn't as explosive as he'd hoped, he decided it was time to plan more long-term.
Having developed numerous bloodline techniques by now, Kiyo had accumulated enough experience and confidence.
"Perhaps... it's time to consider truly fusing the Five Elements..."