Chapter Text
Hatake Kakashi was reborn in his thirteen, just before he killed Rin with his own hand.
He encountered some things that were better than in his previous life, along with some minor problems:
The first better thing: this world's Kakashi was a little stronger than him—he successfully stopped Kiri-rin from kidnapping Nohara Rin.
The connected minor problem: Kiri-rin kidnapped him instead, and he is now the Three-Tails jinchuriki.
The second better thing: this world's Kakashi succeeded in negotiating with the Three-Tails, and he became a perfect jinchuriki who would not go on a rampage in Konoha.
The connected minor problem: Konoha did not want to risk full-scale retaliation from Kirigakure, so she decided to send the Three-Tails jinchuriki back to Kirigakure.
"I think you have one more better thing," Isobu said, lying beside him in evaluation. "Didn't you say that former teammate of yours secretly controls Kirigakure? Now you can meet him sooner, and search together with him for a new way to save the world."
Kakashi remembered that his story ended with "retired Sixth Hokage travels the world," and he had no idea where Isobu got the conclusion that he wanted to become the savior of the shinobi world. But he was very free right now—anyone sealed inside a scroll to keep him from going on a rampage midway would be very free—so he spoke calmly: "I think this should be Naruto's job—or else Obito's, after I successfully talk-no-jutsu him."
Could he successfully talk-no-jutsu Obito? The chances were not great—no matter how eloquent the later Sixth Hokage became, in front of this person he could never say anything. They had missed too many, too many years between them. The Kaguya crisis let them ignore all sense of strangeness and fight together, relying on the resonance between their Sharingan and their rich combat experience to make up for their lack of rapport. But without the crisis of the world hanging by a thread, without a common enemy, Kakashi had to admit that he knew nothing about how to persuade the current Obito.
His greatest hope at present was "Kakashi Hatake did not kill Nohara Rin, so Uchiha Obito will not think this world is fake." But if the many years he had wasted had ultimately taught him anything, it was that one should never rest victory on the thoughts of one's enemy.
Especially when this enemy was also an Uchiha.
No offense, really—it was just that the Uchiha family's thought processes really were a tiny bit different, and Kakashi felt that as a retired old man who had lain flat for many years, he really could not keep up with young people's emotions.
He could not exactly tell the currently youthful and tender fourteen-year-old Uchiha Obito, who had just awakened the Mangekyo and whose Kamui weakness had been seen through by Minato-sensei in two moves, that in the future Ootutsuki would come to Earth like dumplings being dropped into a pot, and that they should go fight Isshiki now, then go obtain that ninjutsu that could change the thinking of the entire world, painlessly uniting all the shin obi of the world to prepare for the arrival of aliens, right?
Wait...
Hatake Kakashi, oh Hatake Kakashi, you need to have the self-awareness of an old man. Is this kind of world-changing thing something for you to do?
—But that is a superior version of Infinite Tsukuyomi with no side effects, you know?
Calm down, calm down. If Kaguya does not die, the Kara organization will not appear either. Even before he was reborn, Konoha had not figured out exactly how Kawaki replaced Boruto's identity. That Amado was most likely also a puppet pushed out front—Hatake Kakashi, what are you letting your imagination run away with?
Just as Kakashi's thoughts had already drifted to summoning the Gedo Statue to break the moon's seal, then driving Kaguya to devour Isshiki and then gathering Sasuke and Naruto together, summoning the Sage of Six Paths to clean up the mess, Isobu felt that he could not keep watching from the sidelines.
"Although Hagoromo only comes out in critical moments, Hamura's chakra consciousness has always been on the moon guarding his mother's seal," Isobu worked hard to dig up memories from a thousand years ago. "Hamura was able to oppose his mother for humanity back then, so now he can also work hard against the Ootutsuki from beyond the heavens for humanity, right? Since you think you are not yet strong enough to engage into this kind of battle, then let's go find Hamura?"
...In short, stop thinking about anything like the Ten-Tails, Kakashi-kun. This is the lifelong request of a tailed beast that only wants to sleep.
Anyway, Isobu would no longer believe Kakashi when he said he was just an accomplished-nothing retired old man—what kind of accomplished-nothing old man's most conservative plan was to make himself into Ootutsuki Isshiki's vessel and then commit suicide, directly preventing the other party from causing trouble in the future?
He was still seriously considering how to leave his memories of the future in his Sharingan, then seal his eyes in a scroll to preserve it, ensuring that when his former teammate recovered the eye, he could incidentally learn and change the future!
—Hatake Kakashi, do you really think only the Uchiha family's thought processes are a little off?
Kakashi knew nothing of Isobu's silent complaints. He only felt that what Isobu said made a lot of sense—he and Obito together had barely had the power to fight in front of Kaguya. Recognizing one's limitations was an essential skill for a shinobi to survive, and assigning the right work to the right people was the Hokage's responsibility—since that was so, was it not only natural to toss the pot to someone who could carry it (a chakra consciousness?)?
Once the thought of lying flat arose, in an instant the world became broad. After thinking this through, Kakashi immediately felt the sky was bluer and the water clearer—and the goal had been set. In short, first peacefully let himself be taken to Kirigakure to rendezvous with Obito, then the two of them would together open Susanoo and fly to the moon to find the Sage of Six Paths' younger brother and hand over the mess. A piece of cake.
As for your saying that his chances of successfully talk-no-jutsu-ing Obito were not great?
No offense again. The Uchiha family liked to open with genjutsu at zero range. As long as Obito saw the future memories in Kakashi's mind, the best future would be Obito suddenly achieving great enlightenment and joining hands with him to lay plans early to save the world. The worst future would be Kakashi having to physically self-destruct to wreck Obito's Eye of the Moon Plan, forcing Obito to have only one path left: open Susanoo, fly to the moon, find Hamura, and save the world.
This is perfect.