Shinji was momentarily stunned, and the look of surprise on his face grew heavier.
This kind of sensation was not unfamiliar to him.
When he had used the Susanoo Tomoshibi to wield his grandmother's Mangekyō Sharingan, his own Mangekyō had produced a similar resonance with hers.
The appearance of this resonance meant compatibility!
That was why, at the time, he had been able to use the Susanoo Tomoshibi to merge the two pairs of Mangekyō Sharingan into one, creating an Eternal Mangekyō Sharingan.
Otherwise, even with his current ocular power, it would have been extremely difficult to forcibly fuse two pairs of Mangekyō Sharingan using the Susanoo Tomoshibi.
Back then, the compatibility had been due to the fact that the two pairs of Mangekyō Sharingan were connected by blood, making it possible to merge them into an Eternal Mangekyō Sharingan.
But the compatibility he was experiencing now left Shinji puzzled.
"Why is this happening?"
He furrowed his brows and fell into deep thought.
One pair was the Hogan, and the other was the Ketsuryūgan. Even if there was a blood connection between the two, it would have been over a dozen or even dozens of generations ago, dating back at least a hundred years.
After so many generations of reproduction, the Hogan clan and the Ketsuryūgan clan were at best distant relatives, and their bloodlines were no longer connected.
Moreover, both the super Ketsuryūgan and the enhanced Hogan had been forcibly fused by Shinji using the Susanoo Tomoshibi, making their bloodlines already mixed and impure.
Therefore, this compatibility could not be due to a blood connection.
With a shift in his thoughts, Shinji narrowed his eyes.
If it wasn't a blood connection, then there was only one other possibility: compatibility in chakra nature.
In other words, the chakra nature of the Ketsuryūgan and the Hogan happened to complement each other to some extent. This was why, when both were wielded simultaneously by the Susanoo Tomoshibi, a subtle resonance was produced, which Shinji, with his prior experience, was able to detect.
This situation was not impossible.
Kekkei genkai were the result of the fusion of two chakra natures.
So, whether the compatibility between the Ketsuryūgan and the Hogan was due to the fusion of chakra natures or the enhancement of chakra properties, it indicated that the two had a certain degree of complementarity.
Having clarified this, the look of surprise on Shinji's face gradually turned into delight.
The fusion of two compatible dojutsu kekkei genkai would yield far better results than forcibly fusing them using the Susanoo Tomoshibi.
Such a fusion often resulted in a qualitative transformation.
The fusion of his Mangekyō and his grandmother's Mangekyō into an Eternal Mangekyō Sharingan was the best example!
At this moment, whether it was the super Ketsuryūgan he had just obtained or the enhanced Hogan from before, both had already surpassed the level of the Tomoe Sharingan. If they could undergo a qualitative transformation through this fusion, the resulting eyes might very well reach the level of the Mangekyō Sharingan.
No!
They might even surpass the Mangekyō Sharingan!
The fusion of two Mangekyō Sharingan was clearly an enhancement of chakra properties, which could be seen as 1 + 1.
But this fusion of the Ketsuryūgan and the Hogan was likely a fusion or completion of chakra natures, which could be seen as A + B.
Although both were fusions, the concepts were different.
In comparison, the fusion or completion of chakra natures was clearly more exciting than a simple enhancement of chakra properties.
After calming his restless mind, Shinji let out a sigh.
He knew very well that, given his current exhausted state, attempting another fusion would be too much of a strain.
Moreover, the difficulty of this fusion might be greater than any previous attempt, and the slightest mistake could result in the destruction of both the super Ketsuryūgan and the enhanced Hogan.
Thus, he forcibly suppressed the urge to proceed with the fusion immediately.
Although the fusion couldn't be done right away, he could still try some experiments. So, he activated the Susanoo Tomoshibi again and replaced the super Ketsuryūgan with an ordinary pair of Ketsuryūgan.
As expected.
Once the equipped eyes became ordinary Ketsuryūgan, the subtle resonance he had felt earlier instantly disappeared.
"Not all Ketsuryūgan can fuse with the Hogan..."
This result confirmed his earlier speculation.
Only the most refined Ketsuryūgan and the most refined Hogan could achieve a fusion or complementarity in chakra nature.
Ordinary Ketsuryūgan or Hogan could not trigger this resonance.
This made Shinji even more excited about the potential outcome of fusing the super Ketsuryūgan and the enhanced Hogan.
After briefly collecting the remains of the Chinoike clan members in Hell Valley, Shinji left the Two-Tails Jinchūriki in the Land of Hot Water and returned to the village.
Without anyone noticing, he replaced his shadow clone and resumed his normal life in the village.
He only had three ordinary pairs of Ketsuryūgan left.
Thus, both the super Ketsuryūgan and the enhanced Hogan in his possession could be considered rare treasures. Therefore, instead of rushing to begin the fusion as soon as he recovered his ocular power, he secretly borrowed the medical team's equipment to test the super Ketsuryūgan and the enhanced Hogan.
The test results were roughly in line with his estimates.
Although the chakra of the super Ketsuryūgan and the enhanced Hogan were primarily Yin-natured, their secondary properties were slightly different.
In the super Ketsuryūgan, aside from the primary nature, he also detected some Water-natured chakra.
In the enhanced Hogan, he detected some Earth-natured chakra.
Discovering this, Shinji felt as though he had unlocked a door to something greater.
Subsequently, he decided to properly adjust his condition and officially begin this highly challenging fusion in three days.
To ensure the success of the fusion, he also needed to make some preparations.
In Karin's apartment.
After finishing infusing Yang Release chakra into the pair of severely damaged Mangekyō Sharingan in her eye sockets, Karin rubbed her eyes.
After days of nourishment, the severely damaged Mangekyō Sharingan had begun to show signs of recovery, although the progress was still very slow.
At that moment, a voice suddenly echoed in her ear: "I'll need your chakra in three days. Be prepared!"
Karin's expression turned serious, and she nodded. "Understood!"
Having her chakra extracted was something she was already very familiar with. When the leader extracted a small amount, he often didn't even inform her.
But this time, the leader's serious tone made her realize that something major was about to happen in three days.
In Haku's apartment.
Haku, who had also received the message, replied respectfully, "Please rest assured, I will be in peak condition in three days!"