Immortality begins with the ninjas of Konoha

(The Naruto arc is complete, with an average of 6400 subscriptions. Readers can continue reading with peace of mind.)
(The One Piece arc "Planting Trees and Cultivating Immortality" is ongoing...)
"Teacher, does the Sage of Six Paths really exist?"
Can a ninja become a sage?
"..."
Tsunade, with her golden twin tails, smiled as she looked at the newly graduated disciple's earnest question and thought to herself, "He's still just a kid after all."
...
"The lifespan of the physical body is far too short!"
"Even the Hokage will eventually perish."
"Xiu, in this village, only you can understand me!"
"..."
In his quest for truth, Orochimaru, who had chosen to defect from the village, looked at the young man who had tracked him down and continued to bewitch him, a fanatical expression gradually appearing on his face.
...
"Shu, a ninja is someone who can endure."
"For the ninja world, the Child of Prophecy will ultimately change everything!"
"..."
Jiraiya knelt in the rain, groaning in anguish. He couldn't believe that his successor, who inherited the Will of Fire, would ultimately go astray.
...
On the earth bathed in the crimson moonlight, Furukawa Osamu looked at the Truth-Seeking Ball in his left hand, which was changing shape, and then at the Chakra Fruit he had painstakingly collected in his right hand, smiling with relief:
"...Immortality begins here..."
-
Osamu Furukawa, who unexpectedly arrived in the ninja world, initially only wanted to live longer.
The pursuit of immortality ultimately changed the entire world, and this was only the beginning.
P.S.: The synopsis is weak, but I guarantee my million-word word count.