"Rinnegan!"
The mere thought of the Rinnegan stirred a deep yearning in Uchiha Fugaku's eyes.
The Rinnegan one of the most powerful dōjutsu was a supremely advanced ocular ability.
This was evident in the original timeline, where Nagato, wielding a pair of transplanted Rinnegan, obliterated Konoha, one of the Five Great Shinobi Villages, with a single strike leaving the village completely defenseless.
And even then, that wasn't the full extent of the Rinnegan's power.
After all, the Rinnegan Nagato used wasn't his by blood. The eyes were transplanted, lacking perfect synchronization with his body. As such, their full power was far from what the original owner could unleash.
"Let's see what abilities this Mangekyō holds!"
He delved into his predecessor's memories, seeking to confirm the abilities of this pair of Mangekyō Sharingan.
This Mangekyō would be his greatest trump card for now. He needed a full understanding of its capabilities.
"The right eye's ability is… True Illusion!"
His eyes lit up.
True Illusion an ability similar to Uchiha Itachi's Tsukuyomi.
Like Tsukuyomi, it could generate a genjutsu space.
But there was a critical difference. While Itachi's Tsukuyomi allowed manipulation of time, space, and mass within the illusion, his True Illusion directly reflected the damage dealt within the illusion back into the real world.
For example, if he slashed an enemy within the illusion, a corresponding wound would appear on the enemy's physical body in reality.
The ability to convert illusionary damage into real-world injury that was why it was called True Illusion.
"A genjutsu stronger than Tsukuyomi!"
In his eyes, True Illusion was clearly a higher-tier technique than Tsukuyomi.
Tsukuyomi only inflicted mental trauma, while True Illusion caused physical harm. The difference in their levels was obvious.
"And the left eye's ability… Corpse Refinement!"
After savoring the right eye's power, he turned to the left eye. The moment he identified the ability, his gaze blazed with intensity.
Corpse Refinement a truly unique dōjutsu.
It allowed him to absorb the corpse of someone recently deceased into his own body, thereby inheriting their talents in genjutsu, taijutsu, ninjutsu, and more.
If the deceased possessed a Kekkei Genkai, he could even transform it into his own.
He wasn't disappointed—the left eye's ability was no less potent than the right's.
In fact, one could argue it was even more valuable.
"Short-sighted fool sitting on a mountain of treasure and never putting it to use!"
Reviewing Fugaku's memories regarding how this power had been used or rather, not used he couldn't help but sneer.
His predecessor had been blind to its value. Despite holding a treasure trove, he never made proper use of it.
As the clan head of the Uchiha, Fugaku had believed his own clan's bloodline was superior in all aspects ninjutsu, taijutsu, genjutsu.
He had scoffed at other clans' Kekkei Genkai, deeming them unworthy of consideration.
Thus, he dismissed Corpse Refinement as a useless technique and never once utilized it.
In his current view, that mindset was idiotic.
To possess such a powerful ability and leave it to rot no wonder the Uchiha were wiped out in the end.
Truthfully, Fugaku's weakness and narrow-mindedness had played a major role in the clan's downfall.
"With Corpse Refinement, my chances of obtaining the Rinnegan have soared!"
Excitement surged through him.
To awaken the Rinnegan, two conditions had to be met: transplanting a pair of closely related Mangekyō Sharingan, and acquiring Hashirama's cells.
The first wasn't a problem.
Uchiha Itachi's Mangekyō was perfect for him. Given their close blood relationship, transplanting Itachi's eyes would likely result in the Eternal Mangekyō Sharingan.
As for their surface-level father-son relationship it was meaningless to him now. Itachi already wanted to kill him. Why should he care about familial ties?
Sparing Itachi's life was already generous enough.
The real challenge lay in the second condition transplanting Hashirama's cells.
This step was extremely risky. A single mistake could lead to side effects, or worse, his body being consumed by the cells.
Even if the transplant succeeded, the fusion with his own body might still be imperfect.
In the original timeline, Uchiha Madara had spent decades refining the fusion before finally awakening the Rinnegan near death.
He believed the delay was due to the imperfect compatibility between Madara's body and Hashirama's cells.
But what if he could use Corpse Refinement to absorb someone who had already perfectly fused with Hashirama's cells?
Then he wouldn't just acquire the cells he'd also achieve perfect compatibility.
In that case, the time required to awaken the Rinnegan would shrink dramatically.
"And beyond the Rinnegan… there are other Kekkei Genkai just as powerful!"
He couldn't help but think ahead.
Without Corpse Refinement, even with his foresight, his ultimate limit might have been just the Rinnegan.
While the Rinnegan would give him the power to protect himself, it wouldn't be enough to stand against the Ten-Tails or Kaguya Ōtsutsuki.
But now, things were different. With Corpse Refinement, he could obtain other top-tier bloodline abilities on par with the Rinnegan.
Like the Tenseigan the eye technique inherited from Hamura Ōtsutsuki, the Sage of Six Paths' younger brother.
He knew how the Tenseigan could be obtained.
By combining the Byakugan of the Hyuga clan with the bloodline of the Ōtsutsuki on the Moon specifically Toneri Ōtsutsuki.
With Corpse Refinement, he could absorb a Hyuga's corpse and Toneri's corpse. That should allow him to obtain the Tenseigan.
"If I can wield both the Rinnegan and the Tenseigan… even Kaguya won't be invincible!"
He couldn't help but feel excited.
Both were incredibly powerful ocular abilities. To possess them simultaneously just imagine the power.
The Sage of Six Paths and Hamura had once sealed Kaguya by working together. If he inherited both of their powers, why couldn't he do the same?
"Truly… a mountain of treasure wasted!"
Once again, he sighed at his predecessor's foolishness.
To possess Corpse Refinement and never once use it to grow stronger…
But to be fair, the original Fugaku lacked the foreknowledge he had. He didn't know the paths to awaken the Rinnegan or Tenseigan.
Corpse Refinement's true potential could only be realized by someone with foresight like him.
In the hands of someone else, at best it might yield a few Kekkei Genkai.
It would boost their strength but never take them to this kind of transcendental level.
"Fugaku, dinner's ready!"
A soft knock came at the door, followed by Uchiha Mikoto's gentle voice.
"Got it."
Fugaku responded calmly, stepping out of the study.
Now that he had a clear path to grow stronger, the anxiousness from his early days after transmigration was gone.
The future was no longer bleak.
He had found his golden finger but it wasn't a gift from transmigration.
It had already been there… waiting for someone who knew how to use it.