According to vague memories from a past life, the Tenseigan, this ultimate weapon, was an upgraded version of the Byakugan, a top-tier power comparable to the Rinnegan.
As far as Hyuga Kagami knew, there were two methods for the Tenseigan's evolution.
The first was like Otsutsuki Toneri, combining the bloodline from the moon with the bloodline of the Hyuga clan's main family on Earth to evolve the Tenseigan.
The second was to fuse a large number of Byakugan.
Hyuga Kagami immediately dismissed this first method; he was neither from the main family nor could he obtain the Byakugan from Otsutsuki Toneri's lunar bloodline. As for the second method, due to the 'Caged Bird' seal, the Byakugan of branch family members would be instantly destroyed upon separation from the body or upon death. Therefore, relying solely on the main family, it was impossible to gather a sufficient number of Byakugan.
Both methods seemed unworkable, but from the second method, Hyuga Kagami had a new idea.
Be it the Byakugan or the Sharingan, all Kekkei Genkai were, in essence, just physical manifestations of genes. If it was impossible to gather enough Byakugan, could one perhaps approach it from a genetic perspective? By collecting a large amount of Hyuga clan genes, then fusing these genes, could the Byakugan be evolved into the Tenseigan directly from the genetic level, from the inside out?
Based on this bold conjecture, Hyuga Kagami focused on learning genetic technology from Orochimaru.
Through continuous study and observation, Hyuga Kagami made an astonishing discovery: within the genes of all Hyuga clan members, there existed 33 sets of special gene sequences.
Through further observation, Hyuga Kagami also found that among different clan members, the number of activated sequences within these 33 special gene sets also varied.
As for Hyuga Kagami himself, only the portion from 17-33 of his 33 special gene sequences was in an activated state, while the 1-16 portion was inactive. The dozen or so other Hyuga clan members from whom he had collected samples were largely the same; only a part of their 33 special gene sequences was activated.
This discovery further corroborated Hyuga Kagami's guess.
He even suspected that if all 33 special gene sequences within the body could be activated, then every Hyuga clan member could evolve their own Byakugan into a Tenseigan.
In an instant, this thought spread wildly in Hyuga Kagami's mind.
Thanks to the war, Hyuga Kagami, who had been assigned to a field hospital by Orochimaru, easily collected a large amount of Hyuga clan genetic material. After screening and comparing over a hundred gene samples, he successfully extracted the activated special gene sequences for the 4-16 portion.
Counting the 17-33 portion of activated special gene sequences already in his own body, he was now only missing the activated forms of the first three special gene sequences (1-3) out of the 33 sets.
Hyuga Kagami had collected more than enough genetic material from branch family members, but none of them had the activated 1-3 special gene sequences. So, naturally, he set his sights on the main family.
However, main family members rarely went to the battlefield personally, and even if they did, they were usually heavily protected, far beyond the reach of a ninja at Hyuga Kagami's level. Thus, he had been unable to obtain a main family gene sample.
For this reason, he had no choice but to ask Orochimaru for help.
Orochimaru didn't refuse Hyuga Kagami, but even for Orochimaru, one of the Sannin, stealing genes from the main family was no easy task.
The matter dragged on for over a year, forcing the experiment to be suspended.
Although frustrated, Hyuga Kagami knew he was just a minor figure struggling for survival. To change his destiny, he had to find opportunities himself; he couldn't just wait for good fortune to fall into his lap.
But just as Hyuga Kagami was setting his sights on the soon-to-be-born Hinata, a main family newborn, unexpectedly, as Orochimaru was bidding him farewell this time, he actually delivered a piece of main family flesh tissue.
While processing the main family flesh tissue, Hyuga Kagami pondered, "Orochimaru's defection should be happening in the next few days. But not only does he not intend to take me with him, he even delivered the experimental materials I urgently need before leaving. What is his intention? To have me stay peacefully in the village as his spy?"
Both from Orochimaru's recent behavior and from his vague memories of his past life, Hyuga Kagami could determine that Orochimaru's interest in the Byakugan had waned. For Orochimaru to still deliver the urgently needed experimental materials at this time was clearly not for Byakugan research, but to appease him.
Thinking of this, Hyuga Kagami secretly chuckled to himself, "It seems the 'Caged Bird' isn't entirely without its benefits!"
Undoubtedly, the decisive reason Orochimaru chose to leave Hyuga Kagami in the village was the 'Caged Bird' on Hyuga Kagami's forehead. Branch family members had no right to defect; once they did, the 'Caged Bird' could directly eliminate Hyuga Kagami. Orochimaru naturally had no interest in taking away a useless corpse.
As the experiment progressed, Hyuga Kagami reined in his chaotic thoughts and focused his attention on the experiment.
The main family flesh tissue sent by Orochimaru was very viable. If Hyuga Kagami wasn't mistaken, this was very likely flesh tissue from the clan head, Hyuga Hiashi, which was also the genetic material Hyuga Kagami most desired.
Because the flesh tissue was very fresh, the gene extraction process was exceptionally smooth. After comparison, he was surprised to find that 28 of Hyuga Hiashi's 33 special gene sequences were in an activated state, and among them were the 1-3 special gene sequences he needed most.
"As many as 28 special gene sequences are in an activated state. As expected of the clan head!"
Thinking of Hyuga Hiashi's Kage-level strength, the musing Hyuga Kagami soon felt a sense of understanding.
Hyuga Hiashi, in his prime, was undoubtedly the Hyuga clan's top powerhouse. It was only natural for such an expert to possess the family's most superior genes.
Pushing aside his musings, Hyuga Kagami concentrated fully on extracting the 3 activated special gene sequences (1-3) that he had coveted for so long.
With this, Hyuga Kagami had collected all the missing activated special gene sequences from 1-16.
"Whether I can defy fate and change my destiny, it all comes down to this!"
Joy, anticipation, apprehension, and uncertainty—all sorts of emotions surged into his heart in an instant, leaving Hyuga Kagami momentarily dazed.
He wanted to roar to the heavens, to freely vent the suppression and fear that had weighed on his heart for so many years, but the one-eyed pit viper on his shoulder made him dispel all such thoughts.
After a light sigh, Hyuga Kagami reined in his various emotions.
Then, calmly, he placed the extracted gene solution into a small thermostatic vial, took out a scroll, and sealed the vial inside it.
Orochimaru's defection would inevitably cause a stir in the village.
To ensure he wasn't implicated, Hyuga Kagami still had many loose ends to tie up. First and foremost was this laboratory; he had to completely erase his own traces from it, even the traces of his experiments, to prevent the village from discovering them and tracking him down, or uncovering the special gene sequence fusion experiment he was conducting.
(End of this chapter)