Chapter 89: The Calculus of Eyes
According to Akira's analysis, the speed of ocular evolution was intrinsically linked to the quality of the catalyst—specifically, the presence of chakra from the Sage of Six Paths or the Otsutsuki clan.
The Sage of Six Paths—Otsutsuki Hagoromo—was a pure-blooded Otsutsuki born after his mother, Kaguya, absorbed the world's chakra fruit. His chakra was Otsutsuki chakra.
Uchiha Madara had awakened his Rinnegan by fusing the chakra of Indra's reincarnation (himself) with that of Asura's reincarnation (Hashirama), thereby drawing out a trace of Hagoromo's latent power. But he'd used only a piece of Hashirama's flesh. The amount of Asura's chakra in that sample was minute, and the quantity of Six Paths chakra needed to spark a Rinnegan was vast. Hence, it had taken him decades of slow integration in his twilight years.
Contrast that with Uchiha Sasuke. He received the Six Paths Sage's direct blessing—a massive, immediate infusion of Hagoromo's own chakra. His unique Magatama Rinnegan had awakened in mere minutes.
The case of Otsutsuki Toneri was similarly instructive. Though a descendant of Hamura, his bloodline was remarkably pure. In terms of Otsutsuki lineage, Toneri's purity likely exceeded that of Indra or Asura, sitting just below Hagoromo and Hamura themselves. Even the main branch of the Otsutsuki acknowledged his identity. Consequently, he could use his own potent Otsutsuki chakra to directly catalyze the evolution of a Hyuga's Byakugan into a Tenseigan.
The logic followed: Hagoromo was Otsutsuki. Therefore, theoretically, his chakra combined with a Hyuga's Byakugan should also be capable of evolving it into a Tenseigan.
In essence, there appeared to be two paths to the Tenseigan. The first was the direct method: combining a Hyuga Byakugan with Otsutsuki chakra. The second was a brute-force approach: amassing a vast number of Byakugan and fusing them, forcing a qualitative evolution. After all, the 'Great Tenseigan' formed from countless eyes was still a Tenseigan.
Akira's mind raced. 'Toneri must be alive on the moon by now. I don't need to reinvent the wheel. If I can obtain a sample of his tissue, I can clone a body with Otsutsuki genetics. Combining that with the Byakugan clone… the path to the Tenseigan becomes straightforward.'
The plan crystallized. He would need to find time to travel to the moon and secure a biological sample from Otsutsuki Toneri. That was the orthodox, proven method.
'But as a contingency,' he thought, a prudent strategist to his core, 'I must prepare an alternative. If our current cloning tech cannot perfectly replicate an Otsutsuki's unique biology, I'll need a backup.'
He would pursue both theoretical paths to the Tenseigan simultaneously. However, his goal was a personal, wieldable Tenseigan like Toneri's, not the planetary-scale 'Great Tenseigan.' The method of mass-fusing Byakugan would need modification. The principle of accumulating pupil power was sound, but the mechanism differed.
Akira's thoughts turned to the Eternal Mangekyō Sharingan. Its evolution required fusing two pairs of Mangekyō, with one set absorbing the pupil power of the other through specific, known methodologies.
Could a similar fusion principle be applied to the Byakugan? Would multiple Byakugan, merged using an adapted version of the Eternal Mangekyō technique, undergo a qualitative evolution?
"The Hyuga clone has the Byakugan," he mused aloud. "It's a perfect test subject. Let's see if the Mangekyō fusion framework can be applied."
He immediately set to work, performing precise ocular surgery on the inert Hyuga clone within its tank. He established the chakra pathways and seals meant to facilitate pupil power transfer and fusion, adapting the Uchiha clan's secret principles to a different ocular structure. The procedure was complete in under an hour. Now, he would wait. If the clone's eyes showed signs of merging or intensified pupil power, the theory had merit. If nothing happened, it was a dead end.
As he observed the silent Hyuga form, his mind wandered to Hyuga Kaoru, the kunoichi who had accompanied him on the fateful mission to Amegakure. She had proven trustworthy, keeping the secret of the Gedo Statue fragments without question. He owed her a debt for that discretion.
'I'll find a way to repay that favor when the opportunity arises,' he promised himself.
A new complication suddenly struck him. 'If I successfully evolve the Byakugan into a Tenseigan… would a clone possessing both Otsutsuki Toneri's genetics and the Tenseigan count as one material or two for the Demonic Mirror Jutsu?'
At first glance, they seemed a perfect, natural pair. But the core issue was that Otsutsuki Toneri was born eyeless. His pure blood did not manifest the Byakugan trait. Therefore, a clone of him would also lack eyes. The Tenseigan and a Toneri clone were separate components; one did not inherently provide the other.
"There's no helping it," Akira sighed, shaking his head. "Toneri is an anomaly, not a true, complete Otsutsuki."
So, the tally stood: the Hashirama clone (peak Yang), a potential Tenseigan-bearing vessel, and a Toneri Otsutsuki clone. That accounted for three of the five fusion slots, leaving two.
"Jūgo's Sage Transformation must claim one of the remaining slots," Akira decided. "The potential of Sage Mode is immense, and the original story never fully explored its zenith." From basic Sage Mode to the transcendent Six Paths Sage Mode was a chasmic leap. In the endgame, against foes like the Ten-Tails Jinchuriki or true Otsutsuki, ninjutsu became nearly useless. Only senjutsu and taijutsu remained effective. Furthermore, true mastery of senjutsu seemed to confer incredible longevity. The animal sages of the legendary regions—the Great Toad Sage, the White Snake Sage, the Slug Sage—had lived for millennia. Even Fukasaku and Shima had weathered nearly a thousand years. For creatures whose natural lifespans were shorter than humans', this was a testament to the life-extending, perhaps even immortalizing, power of deep senjutsu cultivation.
It was a power worth embedding into his very being.
(End of Chapter)
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