In Uchiha Sora's understanding and deductions,
The Mangekyō Sharingan was, in essence, a defective product—
Something forcibly ripened under insufficient conditions.
Only a defective product would require another pair of Mangekyō Sharingan to complete its origin and achieve the qualitative transformation into the Eternal Eye.
Of course—
This also involved factors such as bloodline purity.
But in Sora's view, none of that was a real problem.
With his level of Comprehension, sooner or later he would deduce a method to purify bloodlines.
In fact, he already had quite a few ideas on that front and had gathered a considerable amount of non-critical data.
Most of it had been collected while he was still in the womb—
After all, the growth of his own bloodline at that time had been the best source of data.
What he lacked now was the most crucial piece—
First-hand data from awakening his own Sharingan.
Once he completed that step, deducing a bloodline purification method would no longer be an issue.
"Uh… Eternal Mangekyō? What's that?"
Uchiha Masayuki asked with a confused expression.
"Huh?"
Sora paused, slightly surprised.
"You don't know?"
"Not at all."
Masayuki shook his head.
Uchiha Misa and Uchiha Hao also nodded.
Mikoto, of course, knew even less.
"I thought at least you, Dad, would know."
Sora shook his head, then continued:
"You all know about Madara Uchiha, right? Then do you know that his Mangekyō once went blind, and later regained its sight?"
This time, Masayuki and Misa both nodded.
"We've heard of that. Some clan records mention it as well."
"Does that mean… when he regained his sight, his Mangekyō Sharingan evolved into the Eternal Mangekyō Sharingan?"
"How did he do it?"
Only now did they understand why Madara had been so unique—so powerful.
What he possessed later was no ordinary Mangekyō.
They didn't question how Sora knew all this.
In their eyes, he must have pieced it together through his reading and terrifying deductive ability.
"That's right."
Sora nodded.
"He advanced his Sharingan into the Eternal Eye and regained his vision."
"As for how—"
"He fused the Mangekyō Sharingan origin of his younger brother, Izuna Uchiha."
"What?!"
All four of them were shocked.
Masayuki exclaimed in disbelief:
"How is that possible? He would do something like that? I remember your grandfather saying Madara and his brother were extremely close—why would he…?"
Sora shook his head.
"It wasn't taken by force."
"From what I can tell, Izuna was dying and willingly gave his eyes to his brother."
"Madara then fused the two pairs of Mangekyō Sharingan and completed the evolution into the Eternal Eye."
"But even so—"
"In my view, that method is still imperfect. It's far inferior to a natural, step-by-step evolution."
Not to mention—
This method required the Mangekyō Sharingan of a close blood relative, preferably a sibling.
"Mm."
Masayuki nodded solemnly.
"It is indeed imperfect… and far too cruel."
"This must never be spread. Do you understand?"
He swept his gaze across everyone present and warned:
"Whether within the Uchiha clan or outside it, this information would bring nothing good."
If it spread within the clan—
Who knew what kind of dangers it might create?
If some madman obsessed with power tried to replicate it—
That would be a disaster for the Uchiha.
And if outsiders learned of it—
Not only would they covet the Sharingan even more—
They would also see the Uchiha as inherently evil.
After all—
Taking a sibling's eyes to evolve one's own power was, on the surface, undeniably horrifying.
"Mm!"
"Understood!"
Mikoto, Misa, and Hao all nodded seriously.
As for Sora—
There was no need to say anything. He wouldn't be foolish enough to spread such knowledge.
"Sora!"
Masayuki said seriously:
"Try to figure out a truly perfect method for evolving into the Eternal Eye as soon as possible."
"Our whole family is counting on you."
"I'm not in a hurry to awaken the Mangekyō anymore."
"If that's the kind of flawed method required, I'd rather not have it."
After all, that method required extreme emotional trauma—
Witnessing the death of loved ones to trigger awakening.
He had no intention of walking that path.
"Yeah! It's all up to you, little bro!"
Uchiha Hao echoed.
There was no way he would ever consider taking his father's or brother's eyes.
Even thinking about it would probably get his legs broken by their parents.
And besides—
By that time, he doubted he'd even be stronger than Sora.
"Leave it to me."
Sora nodded confidently.
"You won't have to wait long."
Seeing his confidence, everyone finally relaxed.
…
One month later—
[You study numerous medical texts and body-refining techniques, fully integrating them. Your medical expertise greatly improves and reaches Expert Level.]
…
Three months later—
[Through observing how the Innate Technique strengthens cellular energy and vitality during cultivation, you experience an epiphany and create the Reverse Innate Technique.]
[Reverse Innate Technique]: By reversing the flow of Innate Qi, it consumes Innate Qi to replenish cellular energy and vitality.
"Done!"
Sora absorbed the newly created technique in his mind, a faint smile appearing on his lips.
"With this, I no longer have to worry about damaging my cells or depleting my lifespan when extracting chakra."
As for the consumption of Innate Qi—
That wasn't a problem.
Over the years, he had already accumulated a considerable amount of Innate Qi through the Innate Technique.
Moreover—
The Innate Technique functioned similarly to internal energy cultivation.
Unless something went wrong, consuming a portion of Innate Qi would not reduce his overall cultivation level.
The expended portion could be quickly restored through continued practice.
Thus—
Using Innate Qi to compensate for the cellular depletion caused by chakra extraction was entirely viable.
A nearly perfect cycle.
Of course—
Sora's ultimate goal was still to create a truly integrated cultivation system—
One that could harmonize Innate Qi and chakra.
And more importantly—
One that could draw energy directly from the environment,
Accumulating both Innate Qi and chakra—
Without needing to extract cellular energy or rely on mental conversion.
That—
Was the truly perfect cultivation method he envisioned.