Second Hokage, upon hearing this question, decisively shook his head:
"Now that Madara has become the Ten-Tails jinchuriki, his chakra is extremely easy to sense. This Water Release wasn't done by him."
The Third Hokage felt puzzled, then shifted his gaze toward Kakashi beside him: "Who was trapped in that alternate dimension with Madara? (°ー°〃)"
Kakashi: "Rin…"
Third Hokage: ∑(°Д°)
...
Elsewhere.
Inside Naruto's spiritual realm.
Naruto's spiritual form curiously looked at the strange old man in front of him.
"Old man, who are you? How did you appear inside my head…"
"That staff in your hand—I feel like I've seen it before. And those floating black orbs under your butt…"
After being severely injured by Madara, Naruto's body couldn't move, but his spirit was extremely active.
Then, within his mental world, he saw this bizarre old man!
At this moment, the strangely dressed old man thought for a moment after hearing Naruto's words:
"That indeed is a problem."
"Because I'm not sure whether the name the world knows me by is the same as the name I introduce myself with…"
Naruto: "Huh? (‧_‧?)"
Old man: "I am the embodiment of peace and order. My name is Hagoromo, Ōtsutsuki Hagoromo. ୧⍢⃝୨"
Naruto scratched his head: "Your name sounds familiar, but I can't remember…(||๐_๐)"
"But old man, now's not the time to talk. I have to hurry and get out to save the world. Now that Shinju isn't here, I have to shoulder the duty of protecting the shinobi world!"
Old man: "I know you're anxious, but being anxious won't help right now. You might as well listen to what I have to say first. ┑(￣Д ￣)┍"
Naruto could tell this old man was no ordinary person. Knowing he had no other choice, he sat cross-legged: "Alright, old man, go ahead."
The oddly dressed old man looked pleased: "You calmed down so quickly… you're not much like that foolish son of mine. ´∀`"
Naruto: "Old man, what does your son have to do with me? --003d_--003d"
"Don't rush. Listen carefully." The old man continued.
"First, my identity. My name is Hagoromo, also known to the world as the Sage of Six Paths, founder of Ninshū."
Naruto: ヽ( ຶ▮ ຶ)ﾉ!!!
"You're the Sage of Six Paths?! The one who created ninjutsu? Obito was just talking about your story!"
"I even suspected Shinju might be your reincarnation…"
Sage of Six Paths: "I told you, don't get excited. Let me explain slowly…"
"Next, about your identity. You are the reincarnation of my son Asura's chakra."
"The previous reincarnation of Asura's chakra was Hashirama Senju…"
"But judging by your level of comprehension, you probably won't understand it like that. I'll start from the beginning. 눈_눈"
Naruto: →_→
Sage of Six Paths: "My mother was Ōtsutsuki Kaguya, known in today's shinobi world as the 'Rabbit Goddess'. She came here from a very distant place, and her purpose for coming to this land was to take the chakra fruit from the Divine Tree."
Naruto: "I have a small question—how far is 'very distant'? Did she come alone? Sounds lonely."
Sage of Six Paths: "I don't know. Though it seems she wasn't the only one who descended here, I have never seen the other."
"That's getting off track. Back to the point."
"Later, Mother ate the chakra fruit and gained power, ruling over this world."
"Afterwards, she gave birth to me and my younger brother Hamura."
"Many years passed, and once my brother and I matured, we realized Mother's actions were wrong. So we sealed her with our own hands."
"After that, the shinobi world finally regained peace. I created Ninshū, and I had two children: the elder, Indra, and the younger, Asura."
"I taught them Ninshū, but a huge difference arose between the two."
"To put it simply: a genius older brother and a talentless younger brother."
"Because of this, Indra and Asura walked down different paths."
"Indra was born with powerful ocular abilities and exceptional talent. He relied only on himself for everything. He believed strength alone could acquire all things."
"But Asura, lacking natural ability, had to rely on personal effort and the assistance of others if he wished to gain strength like his brother."
"Through harsh training, Asura strengthened his physical chakra, eventually gaining power comparable to his older brother. He believed that he became strong thanks to everyone's help. He learned the meaning of 'love'—understanding that love makes all things possible."
"And from Asura, I saw new possibilities. So I chose Asura to inherit Ninshū. I thought Indra would support him, but he did not agree with my decision…"
"And so, a struggle between brothers lasting a thousand years began."
"Though their bodies die, the chakra they created continues reincarnating through time."
"And you, Uzumaki Naruto, are the reincarnation of Asura's chakra."
...
Elsewhere.
Inside Sasuke's spiritual realm.
The Sage of Six Paths told him almost the same thing: "And you, Uchiha Sasuke, are the reincarnation of Indra's chakra."
Then, the Sage frowned: "You don't seem shocked. It seems you've already awakened Indra's chakra within you?"
Sasuke nodded slightly.
The Sage nodded: "As expected. Then you should also be able to guess who is the reincarnation of Asura."
Sasuke began thinking. Truthfully, the first person who popped into his mind was Shinju—but he quickly rejected it: "According to the old man, Indra inherited the spirit, Asura inherited the body. But Shinju is overwhelming in both spirit and body…"
"And aside from Shinju, the only person with a bond to me is Naruto…"
...
Back in Naruto's spiritual realm.
Naruto was asked the same question by the Sage.
He answered: "In the entire shinobi world, my bond with Shinju is the strongest. But he's probably stronger than Indra… Other than Shinju, the closest person to me is Sasuke!"
Sage of Six Paths: ∑(✘Д✘๑)
He had considered everything—yet these two idiots identified each other through elimination?! (๑°⌓°๑)
"Actually, I've been observing the Shinju you speak of as well…" The Sage continued, looking troubled.
Naruto eagerly asked: "So, Grandpa Six Paths, do you know Shinju's identity? ( ˝ᗢ̈˝ )"
Sage shook his head: "No. About my mother, I at least know she came from beyond the heavens. But as for that boy—about him, I know nothing…"
"Back to the main topic—my two sons. -_-"
"The previous reincarnations of Asura and Indra before you and Sasuke were Hashirama Senju and Uchiha Madara."
"But Madara caused a serious problem near the end of his time as a reincarnation…"