Naruto: I am Uchiha Seiryu

Seiryu took the letter and his sword, and went alone to the Naka Shrine.

Upon entering, the moment he pushed the door open, violet eye markings appeared at the corners of his eyes—Sage Mode activated. He instantly sensed Black Zetsu's presence in the underground chamber.

'He came in person? Braver than I thought.'

Seiryu grinned inwardly, headed quickly to the entrance, and went in.

Black Zetsu, sensing Seiryu's arrival and seeing him armed and in Sage Mode, tensed up.

But he quickly composed himself, pretending to be calm, and hid behind the Uchiha clan's sacred stone tablet.

When Seiryu stood before the tablet, Black Zetsu finally spoke:

"You've come, descendant of mine."

Seiryu said nothing, but raised his hand and set a barrier around the tablet with natural energy.

Seeing Seiryu act so decisively, Black Zetsu dared not play tricks and hurriedly emerged as a shadow from behind the tablet. "Descendant, please calm down. I mean no harm."

"Descendant? So, now even rats like to claim seniority? Last time someone pretended to be Lord Madara, now you want to claim you're my ancestor?" Seiryu sneered.

"I truly am your ancestor, the original source of the Uchiha bloodline, one of the Sage of Six Paths' sons—Indra's will."

'Wow, this guy's really going all in with the seniority trick.'

Seiryu resisted the urge to smirk and drew his sword.

"Since you've mastered Sage Mode at one of the three great sanctuaries, you must have heard of me, yes? There's no need for hostility. My power is only a fraction of what it was; I'm no threat to you. The reason my will persists is to guide lost descendants to the true meaning of peace."

"Is that so?" Seiryu narrowed his eyes and sheathed his sword. "The one who taught me Sage Mode did mention the source of our bloodline. If you claim to be the will left by our ancestor, show me proof."

Black Zetsu relaxed a bit when Seiryu put his sword away, but hearing the demand for proof, he sighed inwardly.

'This guy's much harder to fool than Madara.'

Still, Black Zetsu was prepared. He said, "If you want proof, use your eyes to carefully examine the tablet."

"The tablet?" Seiryu activated his Mangekyō Sharingan and looked at the stone.

"All it describes is a way to avoid blindness from overuse of the Mangekyō's power. There's nothing like what you mentioned—this information is available to every clan leader." Seiryu was disappointed; he'd already checked the stone after awakening his Mangekyō and expected more.

"Your eyes can't see the truth above. Only the Eternal Mangekyō can pierce the mist," Black Zetsu replied.

"Are you messing with me?" Seiryu's face turned cold, hand on his sword. "I don't have a blood relative with Mangekyō to evolve my eyes to Eternal Mangekyō."

"Calm down, descendant. Since my physical form passed to the Pure Land, I have witnessed many Uchiha geniuses here. Some have advanced their Mangekyō in other ways."

"Oh? Like who?" Seiryu pressed.

"For example, 1,700 years ago, a Uchiha genius named Uchiha Asahi. Like you, after awakening the Mangekyō, he was fortunate enough to obtain Sage Jutsu from the three great sanctuaries, and his eyes evolved during training, reaching the Eternal level," explained Black Zetsu.

"I've never heard of that. The clan may not keep detailed histories, but any method of power advancement should have been preserved," Seiryu frowned.

"He failed when trying to break through to a higher level, and realizing this unnatural method was too dangerous, he destroyed all records to protect future generations."

"So how do you know?" Seiryu demanded.

"As I said, I have always watched over the Uchiha," Black Zetsu answered.

After speaking, a scroll appeared before Seiryu.

"This scroll is the backup I kept. Consider it a meeting gift from your ancestor. Whether to use it is up to you."

Seiryu's eyes flickered as he picked up the scroll and read it. It recorded a training method combining ocular power with natural energy.

'Did this ancestor learn Sage Jutsu at the Shikkotsu Forest?' Seiryu wondered.

'Is this real, or a trap laid by Black Zetsu?'

Seiryu wouldn't foolishly try it right away, but after mastering Sage Mode, he had found that natural energy did nourish and heal the Mangekyō—though very slowly, Sage Mode did reduce its consumption. So this method was probably viable, but Black Zetsu might have hidden tricks in the scroll.

If Black Zetsu knew Seiryu's thoughts, he'd cry injustice! Everything he said was true. The scroll really was created 1,700 years ago by a Uchiha genius who almost surpassed both Indra and Asura's reincarnations. But he died trying to go even higher. Black Zetsu, to prevent another tragedy, later stole and preserved the scroll. He only brought it out now to gain Seiryu's trust.

Seiryu memorized the scroll, and then tossed it back.

"You really are our ancestor, Indra's will?"

"Of course," Black Zetsu nodded.

"Then why show yourself now?" Seiryu asked.

"I've been waiting for a descendant who can truly inherit my will and bring eternal peace to the ninja world," Black Zetsu replied. "Would you like to hear my story?"

Seiryu showed interest without saying a word, so Black Zetsu began:

"My father, the Sage of Six Paths, founded Ninshū and spread chakra across the world. I, building on that, created the prototype of modern ninjutsu.

"When he grew old, he wanted to pass leadership of Ninshū down, but was swayed by my foolish brother's unrealistic ideals and passed the position to him."

"Your brother?" Seiryu prompted.

"Asura, the ancestor of the Senju and Uzumaki clans," Black Zetsu explained.

"I see. No wonder the Uchiha and Senju fought for a thousand years," Seiryu nodded. "But it was unwise for the Sage to pass over the eldest for the youngest; that brings disaster."

"My brother Asura fantasized that chakra could be a bond between people and bring peace, but he didn't consider that unchecked human greed would only grow without power to suppress it.

"I wanted to stop him, but, bestowed with all of our father's gifts, he was too strong. I failed," Black Zetsu sighed.

"My true form foresaw the endless conflict that would come from my brother's naivety. Before dying, I turned my obsession into my current form, forever watching the ninja world. And time has proved me right."

Seiryu: …

He almost wanted to argue, but realized Black Zetsu's words were true—just from another perspective.

"So, ancestor, what have you done all these years?" Seiryu acted as if he were starting to believe, even changing how he addressed Black Zetsu.

"All these years, I have waited for descendants to inherit my will and guided them toward true peace," Black Zetsu said.

"For example?" Seiryu asked.

"For example, decades ago, Uchiha Madara, who obtained the Eternal Mangekyō," Black Zetsu replied.

"So you guided Lord Madara?" Seiryu asked with a half-smile.