Thinking this far, Takuno gently rubbed his slightly weary brow. In the original work, these two Ninjutsu were essentially never used separately.
So, he had originally thought these two techniques were part of a single Ninjutsu called the Creation Rebirth Technique, not realizing they could be employed independently.
However, he understood clearly that while these techniques could theoretically be used alone, any opponent requiring the unsealing of the Yin Seal to face would undoubtedly be of a life-or-death caliber.
Therefore, on such a critical battlefield, the Yin Seal, the Creation Rebirth Technique, and Creation Rebirth would inevitably be activated simultaneously, working in concert, with no possibility of being used in isolated isolation.
But, that applied to others. Takuno himself might not need to follow this pattern.
From his perspective, the value of the Creation Rebirth Technique seemed somewhat limited for him personally.
The reason lay in the fact that its strengthening foundation was still "ordinary Chakra," merely triggering a "qualitative leap" in combat power through an instantaneous "quantitative change."
From this understanding, the Creation Rebirth Technique resembled more of an artificially created "pseudo-sage art," simulating the comprehensive power amplification effect of sage arts, yet lacking the essential sublimation and Natural Energy characteristics of Senjutsu Chakra.
And Takuno's future direction was to master the more fundamental Cursed Seal Mode.
In the progression sequence of sage arts, Cursed Seal Mode was undoubtedly closer to the true threshold of sage arts than a "pseudo-sage art" like the Creation Rebirth Technique.
Comparing the two, he naturally leaned more towards delving into and mastering Cursed Seal Mode.
Conversely, the mechanism of Creation Rebirth sparked intense interest in Takuno.
As he delved deeper into its operational principles, he discovered that once activated, this technique would release vast Chakra energy by unsealing the Yin Seal on the forehead. This energy would then transform into dark blue curse mark patterns covering the entire body, enabling the body's regeneration process to achieve complete "automation."
Any damage could be instantly repaired upon pattern activation, requiring no conscious control from the user.
But the crux of this technique's problem also lay here. The cost of this "full automation" was extremely high. No matter how minor the injury, even a mere skin abrasion, the body would trigger the highest-level complete regeneration program, leading to a severe and sustained overdraft of precious Chakra.
This characteristic reminded Takuno of the research field he was diligently exploring: Elemental Sealing Techniques.
The two shared a startling similarity in core logic. Creation Rebirth was like a pre-set, automated defensive seal focused solely on "self-repair."
Once Chakra was input, this built-in program would begin running, continuously repairing the user.
How remarkably similar this was to the "automated defensive Sealing Jutsu based on rules set for specific attributes" he envisioned!
The only difference was that the Sealing Jutsu he designed aimed to automatically defend against external attribute attacks, namely the Five Elements Release Techniques, while Creation Rebirth was a sophisticated sealing model that utilized Yang Release Chakra to "automatically repair one's own physical body."
Once he comprehended and mastered Creation Rebirth, it would be equivalent to obtaining an extremely precious high-level application template and control pathway for Yang Release Chakra.
Thus, the only attribute missing from the Sealing Jutsus inscribed on his body would be the Yin attribute.
However, the greatest challenge before him lay precisely in this. The essence of the Yin attribute was considered pure spiritual energy.
To utilize this energy within the Sealing Jutsu system and apply it to the equally intangible spiritual plane presented a difficulty that left him deeply troubled.
Takuno pondered repeatedly. Since the core of Yang Nature Sealing Techniques lay in repairing and activating the physical body, then by analogy, should the breakthrough point for exploring Yin Nature Sealing Techniques focus on the direction of repairing the spirit and healing the soul?
His fingertips tapped slowly and rhythmically on the desk. After a long contemplation, he ultimately dismissed this still somewhat hasty line of thought.
Creation Rebirth could be considered a serendipitous discovery, not a universal law of exploration.
Under normal circumstances, mastering the essence of a power must come first, solidly, before higher-level application and innovation can proceed.
Therefore, delving deeply into Yin Elemental Sealing Techniques at this current stage was premature.
Truly effective exploration must wait until he successfully awakens and gains control over the Mangekyo Sharingan.
Only by relying on the Susanoo brought forth by this powerful ocular power could he experience the most fundamental usage method of Yin Release.
Then, he could comprehend the mysteries of Yin Release's spiritual energy more precisely and subtly, thereby laying the indispensable foundation for ultimately conquering Yin Elemental Sealing Techniques.
Takuno's gaze moved slowly across the scroll, finally settling on the technique "Yin Seal."
As a prerequisite Ninjutsu for both the Creation Rebirth Technique and Creation Rebirth, it indeed held some value, with its core lying in its Chakra storage capability.
However, weighing his own Chakra reserves, Takuno realized helplessly that for his current self, the amount of Chakra the Yin Seal could accumulate was a mere drop in the bucket.
Rather than using this precious storage to support those limited regeneration or amplification effects, it would be better to make the most of it.
For example, by eating more in daily life to absorb more nutrients, deliberately converting extra Chakra from food to store within it, allowing him to conduct research for even longer periods.
But all these calculations paled in comparison to the waves stirred in his heart by another bold hypothesis: Could the Yin Seal store Senjutsu Chakra?
If possible, then the value of this Yin Seal technique would increase infinitely!
This thought, once it surfaced, made his breath tighten slightly.
After all, the time limit of maintaining Sage Mode had always been a problem plaguing all sage art users.
Of course, the Three Great Sage Regions likely each had their own solutions, he quickly sorted through in his mind.
First was Mount Myōboku, the one he was most familiar with. Its representative method was the "Sage Art: Amphibian Technique."
This method fused a summoned sage toad with a part of the user's body, cleverly separating the "stillness" required for tranquilly sensing Natural Energy from the "movement" of intense combat. It greatly extended the duration of Sage Mode in actual combat and maximized its utilization.
The path of Ryūchi Cave appeared more direct and brutal.
Judging from the form displayed by Yakushi Kabuto, or rather, Orochimaru-Kabuto, the Sage Mode there almost eliminated the shackles of time limit, but the cost was equally astonishing.
The user's body would irreversibly and permanently transform into a bizarre half-human, half-snake state.
The secret method of Shikkotsu Forest remained an unknown.
The sole known user, Hashirama, who possessed a natural Sage Body, was himself nearly a vessel for Natural Energy, requiring no external aid for condensation.
However, Takuno firmly believed that as split bodies of the Slug Sage, those summoned slugs must be proficient in Senjutsu Chakra manipulation and very likely mastered alternative methods similar to the "Sage Art: Amphibian Technique," though it was never necessary to reveal them on Hashirama.
Now, he had formed a summoning contract with the ultimate existence of Shikkotsu Forest, the Slug Sage, theoretically possessing the entry ticket to learn Shikkotsu Forest's Sage Mode.
But to go or not to go? This became a huge doubt Entanglement in his heart.
The root cause was that he could not be one hundred percent certain that the Slug Sage would not inform Tsunade of his actions.
Although the Slug Sage's nearly eternal lifespan should render it disinterested in human conflicts, let alone harbor malice towards him, the world is unpredictable. The shadow of "what if" always lurks quietly —
Sage Mode—
If he could truly master this power, then the crude and dangerous Cursed Seal Mode would become particularly redundant.
His thoughts jumped and connected between the Chakra storage of the Yin Seal, the automatic formation of Senjutsu Chakra in Cursed Seal Mode, and the ultimate power of Sage Mode.
If he could truly link them together, then perhaps there would be a considerable gain.
After a long while, a clear direction gradually coalesced in his mind.
Perhaps the core value of the Cursed Seal lay not in its pseudo 'Sage Mode,' but in the instinctive trait of automatically absorbing Natural Energy itself!
Jugo was a perfect example. He was born with this ability, but due to his inability to precisely balance the ratio between Natural Energy and his own Chakra, the energy remained rough and mixed, making uncontrollable rampages his inevitable fate.
The petrified frogs of Mount Myōboku and the piles of white bones in Ryūchi Cave were all terrifying consequences of this imbalance.
Although Jugo relied on his 'Sage Body' to narrowly escape death, the price of his loss of control was his mind being eroded by endless madness.
Of course, besides this, there was another possibility for Jugo's rampages: that Natural Energy was also divided into different types.
For example, the toads of Mount Myōboku, the snakes of Ryūchi Cave, and the Otogakure Four under the Cursed Seal Mode all transformed into different animal forms.
Jugo could not accurately absorb the same type of Natural Energy, nor did he understand the balance point of Senjutsu Chakra, so he would naturally rampage.
Extrapolating from this, if one could precisely master the balance point of Senjutsu Chakra and then use the Cursed Seal to achieve automatic absorption of a single type of Natural Energy, then would it be possible to—bypass the most time-consuming stage of Sage Mode *Cultiv* at Mount Myōboku:'sensing and gathering Natural Energy'?
Thinking of this, Takuno's heartbeat involuntarily quickened.
Even better, right before his eyes was an excellent 'research partner'—Jugo!
His unique Sage Body was a natural insurance, capable of withstanding the risks of exploring the limits of Natural Energy imbalance in experiments without excessive worry about his life or death.
Going a step further, if he could combine Hashirama's cells with Jugo's characteristics to deeply research the mysteries of the Sage Body, ultimately achieving a spontaneous, flawless, perfect fusion of Natural Energy and Chakra within the body—
That would inevitably forge an ultimate combat form of Sage Mode rivaling Hashirama's!
A surge of heat intense enough to ignite his soul instantly coursed through his entire body, and Takuno's eyes also grew unusually hot.
That would not merely be an evolution of combat mode, but a revolutionary breakthrough in the understanding and application of Ninjutsu!
However, if the technology for the Cursed Seal to automatically absorb Natural Energy were ultimately realized, then the experiment of storing Senjutsu Chakra in the Yin Seal would seem to lose some of its urgency. At that point, using it merely to store ordinary Chakra would be more than sufficient.
Of course, all of this still needed to be verified through experiments. Takuno calmed that burning excitement; getting so worked up now was clearly not right.
As the saying goes, the greater the hope, the greater the disappointment.
Even if this experiment couldn't succeed, he would still have Cursed Seal Mode as a fallback, and he could even learn Sage Mode from Jugo.
So, he just needed to experiment boldly and without worry. If he succeeded, his strength would see a significant boost. Even if he failed, his strength would still improve somewhat.
No reason to be discouraged!
Finally having calmed that excited mood, Takuno glanced at the timepiece and was slightly taken aback.
Merely the preliminary study of those three jutsu and the subsequent flights of fancy in deduction had actually consumed such a long time.
He suddenly remembered he had promised to visit Minato's home, and the other's time off work was imminent.
As a guest, being late would be truly impolite.
He stretched his body, which had grown slightly stiff from sitting too long, and without further delay, quickly stood up to organize his things.
Pushing the door open, he merged into the twilight street scene of Konoha.
His steps were hurried, but he did not forget the necessary etiquette for this visit. Passing by a shop on the street, his pace naturally slowed half a step as he considered what suitable gift to bring for the house call.
Takuno, carrying a case of fresh milk specially prepared for little Naruto, arrived at the familiar wooden door of Minato's home.
Just as he was about to reach out to knock, the door creaked and slid open half a panel outward, as if anticipating his arrival.
A cheerful gust of wind squeezed out from the crack in the door, immediately followed by a small figure suddenly darting out.
Takuno watched as the child, just over two years old, bumped headfirst into his leg. The small body wobbled like an unsteady little ball.
He instinctively bent down to steady the child, and only then did he see clearly: jet-black short hair soft as ink, chubby cheeks glowing with healthy color, a pair of bright black eyes shining with innocent light. It wasn't little Naruto, but Sasuke.
Sasuke seemed startled by the sudden collision, shrinking his neck, his small mouth slightly agape but not crying out, just looking at him innocently.
"Sorry, sorry! This child was in a hurry to run out and has offended you!" A gentle voice came from inside the door.
Mikoto approached quickly. She wore simple, elegant clothing, her long black hair loosely tied up, her face bearing a mother's concern and a hint of apology.
"Sasuke, apologize to the uncle," she said softly, her tone mixing reproach with doting.
Takuno crouched down, smiled slightly, and gently placed his large hand on top of Sasuke's head, feeling the fine, soft hair. "Little one, don't panic. It's good you didn't fall this time."
His voice was kept gentle. "Remember to walk closely with your mother from now on, okay? If you run around, your mother will worry."
Sasuke looked up at his face and nodded seriously. "Mm, I understand."
That little appearance, obedient yet tinged with a bit of stubbornness, made it somewhat difficult for Takuno to connect it with the future 'Second Pillar.'
Takuno smiled. He hadn't expected to encounter Mikoto and Sasuke at Minato's home.
However, upon careful thought, he wasn't that surprised. Fugaku's intentions were actually quite easy to understand: he wanted to draw closer to Minato.
Coincidentally, Mikoto was also a mother of two children, and she had an Sasuke who wasn't much older than little Naruto. Discussing child-rearing experiences with Kushina was just right.
Moreover, Sasuke could also become a friend for little Naruto.
Additionally, Kushina had some connection with Uchiha Mikito during her pregnancy because they were both expectant mothers.
So, from Fugaku's perspective, with such wonderful conditions, why not go for it?
Standing up, Takuno's gaze swept over the scene inside the door. The Namikaze family stood beside the entryway, their smiles brilliant.
The blond Fourth Hokage, Minato, raised a hand in greeting and said cheerfully, "You're here, Senpai! We were just talking about you."
Kushina stood beside him, her red hair dancing in the light. Next to her, little Naruto was still staring intently at his little friend, Sasuke.