"So, the fact that you spent a month over there, yet only a few minutes passed here can be explained, because it was all an illusion."
This Kakashi has a bit of experience. He once fell for Uchiha Itachi's Tsukuyomi, enduring the sensation of being stabbed by a ninja blade for seventy-two hours, though in reality, only an instant passed.
"It can't be an illusion. If it were, then how do you explain this?" Uzumaki Naruto took out the photograph of him and the Fourth Hokage, handing it to Kakashi.
Staring at the picture of a beaming Namikaze Minato and Uzumaki Naruto, Kakashi's expression changed.
If not for time travel, this photo could not theoretically exist, because Namikaze Minato in the photo looks only four or five years older than Uzumaki Naruto.
While there are methods to create such a photo, like using the Transformation Jutsu, it clearly wasn't the case here.
"Kakashi-senpai, it's definitely not an illusion. This is the Flying Thunder God Kunai that Mokgetsu-senpai gave me before the battle with Mukade. Could an illusion create something out of nothing?"
Yamato took out the Kunai with the Flying Thunder God Mark from his ninja pouch.
"Not only do I have a photo with my father, but there's one with you too, Kakashi-sensei."
Uzumaki Naruto proceeded to pull out more photos, including one with Obito, and a group photo of Mokgetsu, Minato, and their three disciples, as well as one with everyone together.
"Obito, Rin..." Looking at the old friends in the photo, identical to his memories, Kakashi fell silent.
Especially the group photo of Mokgetsu, Minato, and the three disciples made memories rush uncontrollably to Kakashi's mind, his composure shaken deeply.
"Besides the Flying Thunder God Kunai, I can also use the Ninjutsu Mokgetsu-senpai taught me." With that, Yamato demonstrated a flawless Water Array Wall defense and a highly cutting Water Cutting Wave.
"Kakashi-sensei, do you honestly not remember anyone like Mokgetsu-senpai?" Uzumaki Naruto asked again.
Kakashi shook his head. What Uzumaki Naruto and Yamato experienced wasn't an illusion, but he truly had no recollection of a ninja named Habu Mokgetsu.
"If such a ninja named Habu Mokgetsu was as excellent as you say, and resembled Minato-sensei so much, how could I forget someone like that?" Kakashi replied.
Now, he really couldn't make sense of what was happening.
"Tell me everything about the young Kakashi you encountered—his age, ninja level, all the Ninjutsu he used." After careful thought, Kakashi prompted.
Though memories related to Obito and Nohara Rin had faded, Kakashi knew well what abilities he possessed at each stage of his life.
"He seemed to be ten years old, though he hadn't had a birthday. His ninja level was Chunin, but despite the Chunin rank, his strength exceeded some Jonin. His sharp Lightning Release Blade Technique in full combat could instantly kill an ordinary Jonin. As for Ninjutsu, he primarily used Lightning Release and Earth Release. There's also a non-hand-sealed, powerful purple lightning Lightning Release..."
Yamato recollected and shared every detail about the young Kakashi.
Kakashi was stunned. Being under ten and capable of defeating Jonin, what kind of powerful Lightning Release Blade Technique was that? He was Kakashi, after all, yet he didn't know any of this.
At this point, Yamato voiced his inner doubt, "Kakashi-senpai, your Lightning Release Blade Technique was so strong, why don't you use it now?"
Kakashi: ...
He had no idea what Yamato was talking about. Was that truly him?
"The Kakashi you encountered, that wasn't me." Kakashi concluded.
"I'm not referring to age; he simply wasn't me. Even if I became Jonin at twelve, I had no technique guaranteed to instantly defeat Jonin, nor did I have any Lightning Release that was purple lightning."
Not only did his skills and Ninjutsu differ, but Kakashi recalled that at that age, he was still withdrawn. The Kakashi Yamato described sounded somewhat like him now, albeit excessively serious.
Uzumaki Naruto looked at the photos, then at Kakashi, "Are you saying that's not you?"
"Even though he resembles the old me, he definitely isn't me,"
Kakashi declared with unwavering certainty. How could Uzumaki Naruto or Yamato know Kakashi better than he did?
"You might not have traveled back in time; instead, you might have gone to another world," Kakashi proposed his hypothesis.
"While this world closely resembles ours, having Hatake Kakashi and Namikaze Minato, it ultimately is a different world, one that has Habu Mokgetsu, perhaps just as our world might have people that world doesn't have."
Kakashi jumped up, plucking two leaves from a tree to show Uzumaki Naruto and Yamato.
"These two leaves seem the same, but if you look closely, there are slight differences in size, thickness, and shape. Perhaps that's how our two worlds relate to each other, similar but not identical."
This was the most rational explanation Kakashi could devise, perfectly addressing all the existing dilemmas.
After hearing Kakashi's words, Yamato felt enlightened; this explanation made everything make sense. Despite revealing so much about the future, history remained unchanged, which evidently was illogical.
Uzumaki Naruto struggled to describe his current emotions.
The good news: Obito and the others may not fail, and his father, Mokgetsu, Jiraiya might live into the future.
The bad news: This future is not their future; his father and Jiraiya-sensei in this world will never return.