Whether it was the legend of the Hyuga clan's origin on the moon or the theory that their true ancestral name was once different, Uchiha Kai didn't fabricate it.
He looked at Hyuga Aya with calm certainty, unfazed by skepticism.
His composure made Aya hesitate.
Sure, Kai's claims sounded outrageous. The Hyuga clan, descendants of the Otsutsuki and originating from the moon? A different surname—Okanmu? It sounded absurd.
But Kai said he had evidence—aged texts and fragments still undergoing restoration. He even encouraged Aya to investigate it herself.
"The documents I found are incredibly old," Kai said. "Some written in archaic scripts, some damaged beyond easy recognition. But with your growing status in the clan, you might be able to get access. Maybe even test Hiashi on what he knows."
Aya gave a slow nod.
He was right—she couldn't rely on him alone. And he'd offered enough hints. A few nudges in the right direction, and maybe… just maybe, she'd uncover something real.
Still, testing Hiashi seemed like a hassle. It might be easier to simply request access to the main house's archives.
Knowing that Kai was pursuing the Hyuga's ancient roots seriously, and that he already had some fragments—however speculative—made her put the matter on temporary hold.
At the very least, his findings deepened her understanding of the clan's history, especially its ties to the Otsutsuki and the Byakugan's ancient connection.
As for "evolution"… she was beginning to accept that the path might be similar to the Uchiha's. She'd grown familiar with Kai's unorthodox methods. His experiments provided data of immense reference value.
With that research temporarily shelved, Aya shifted her attention to Orochimaru's records. And Uchiha Kai, for his part, turned back to his own goals.
Killing Danzo had brought unexpected gains—and Kai intended to make the most of them.
"The stronger I become, the safer I am," Kai muttered to himself.
The Nine-Tails incident was less than three months away. If Obito, empowered by Uchiha Madara's legacy, decided to escalate things…
"Right." He suddenly remembered something. Turning to Aya, he said, "For your birthday—prepare your documents. I'll be submitting your promotion for Jonin."
"You remembered?" Aya blinked. "Wait—Jonin? Or special Jonin? You know I'm not exactly trying to take on students."
"You're working with the Konoha Security Division. You won't have to." He smirked. "Just prepare. It'll benefit you more than you realize."
Aya paused, then nodded. "Alright. I'll give you the files this week. I've met the qualifications anyway."
She had, long ago.
During the war, Aya completed high-level missions across numerous categories. She just never sought formal promotion, nor was she fast-tracked like Kai had been by the Third Hokage.
She was still technically a Chunin.
Sometimes she wondered if Hiruzen regretted that now.
"With my backing, even if you weren't qualified, you'd still get through," Kai said with a faint smile as he turned and walked away.
The underground laboratory was massive. Ever since the Root's failed infiltration, he'd fortified the structure.
It couldn't rival the secrecy of Danzo or Orochimaru's labs, but it was secure enough.
Kai soon arrived at a large, empty room, sealed the door, and stepped into the center.
He activated his Sharingan—three tomoe swirled in his eyes.
Dark chakra exploded around him, forming the skeletal frame of a Susanoo. Its crimson eyes glowed, its skeletal arms flexing under his control.
Even in its partial form, the power was enormous.
He remembered the clash with Danzo. The third-stage, armored Susanoo had consumed vast amounts of his Mangekyō Sharingan's chakra, but it was worth it.
Recovery had gone better than expected. Thanks to a serum derived from White Zetsu cells and Eternal Mangekyō cells, his pupil power regenerated faster than normal.
"As long as I don't burn through it recklessly, I can fully recover over time," he muttered.
Now, he focused on refining the third stage—adding muscle, armor, and stability.
It took over an hour of steady control. Far slower than his ten-minute construction of the first stage, even in three-tomoe form.
But it was a leap forward.
The second stage, which he used to kill Root agent Ryoma, unleashed power rivaling some S-rank ninjutsu.
If he could master the mature form—the fourth stage—he'd enter a tier where each swing of his sword could match or surpass S-rank techniques.
Uchiha Madara's matured Susanoo had crushed the Allied Shinobi Forces' morale. His complete form carved through mountain ranges.
"Still far off," Kai whispered. "The third stage alone pushes my limits without Mangekyō."
He opened his eyes—Mangekyō activated.
The frequency resonance that once burdened him now felt natural. His chakra solidified into a more complete Susanoo.
This time, the sword hung from the waist—not the back.
"It's adapting to my own fighting style?" Kai chuckled. "Interesting."
He also noticed the size: about six meters now, smaller than the 8-meter height during the Danzo battle.
Still, the change wasn't alarming. Susanoo growth wasn't linear. The complete form could reach over 100 meters tall, after all.
"What matters is that this version doesn't drain me. And it's more than enough to face a disoriented Nine-Tails…"
Training became routine.
Aya buried herself in Orochimaru's data. Her progress was astonishing. Compared to her earlier efforts, this was like switching from crawling to sprinting.
Orochimaru's notes were organized, concise, and brilliant—miles ahead of anything he left behind in abandoned labs.
Even basic learners could follow his notes.
Aya realized then why Kai had been so fixated on Orochimaru's reports.
She suspected he'd found those records during their last mission—when Kenta's battle with Orochimaru ended abruptly.
Maybe Orochimaru had burned the evidence to cover his tracks, inadvertently pushing Kai into murdering Danzo.
Now, with access to these records, Aya gave her all. She was devouring knowledge.
Kai watched her with mild concern. That fire in her reminded him of himself, years ago.
Weeks passed. Kai perfected the second stage Susanoo in three-tomoe state. But he knew full well, training battle readiness.
Then, just as he was wrapping up, Kenta Imai showed up with something strange.
"Hot springs?" Kai blinked. "Why are you giving me a ticket to a hot spring?"
"Just want to chat. Nothing more." Kenta didn't smile this time.
Kai squinted. The lab was private. So was his office at the Konoha Security Division.
"Trying to get cozy, huh?" he asked.
Still, it wasn't a bad idea. A bit of downtime was rare. He hadn't been to a hot spring in years.
"Alright. Let's go," he said, sighing. "Just tell me it's not mixed-gender."
"What are you thinking?" Kenta snorted. "Of course it's separate."
Their conversation continued later—awkwardly, as they washed in the public bath.
Kai found it embarrassing. Kenta didn't seem to care.
"So… what's the big issue?" Kai asked.
"The clan," Kenta replied flatly. "The elders hate what I'm doing. And they hate that I'm working with you."
Kai wasn't surprised. The Senju clan, once dominant, had been reduced to myth.
Kenta explained: the younger generation hated the Third Hokage for weakening the clan. But the elders? They still clung to Tobirama's doctrines.
And they despised the Uchiha.
"Just as I thought," Kai nodded. "The divide was obvious. But I'm guessing things are getting worse now?"
"Yeah. I didn't sign up for this much pressure. But now I have to carry it."
He fumbled the soap, causing it to fly out of his hands—then slipped and fell to his knees.
"You're a ninja, aren't you?" Kai rolled his eyes, leaning forward. "Want help getting up?"
Unbeknownst to them, Kakashi and Might Guy had entered the bathhouse too.
They froze in horror when they saw Kenta kneeling in front of Kai.
"Did… did we see that right?" Guy whispered.
"I think we should double-check," Kakashi muttered.
"...Let's go back in and be sure."
They peeked again—and their expressions twisted in horror.