Immortality begins with the ninjas of Konoha.

"Teacher, does the Sage of Six Paths really exist?" "Can a ninja become a sage?" "..." Tsunade, with her golden twin tails, smiled as she watched her newly graduated disciple's earnest questions, thinking to herself, "He's still just a child." ... "The lifespan of the physical body is far too short!" "Even the Hokage will eventually perish." "Shu, in the village, only you can understand me!" "..." Orochimaru, who had chosen to defect from the village in pursuit of truth, looked at the young man who had followed him 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 chosen one will ultimately change everything!" "..." Jiraiya knelt in the rain, roaring in anguish. He couldn't believe that the descendant 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 Balls changing shape in his left hand, then at the Chakra Fruit he had painstakingly gathered in his right, and smiled with relief: "...Immortality begins here..." —Furukawa Osamu, who unexpectedly arrived in the ninja world, initially only wanted to live longer. However, his pursuit of immortality ultimately changed the entire world, and this was merely the beginning. PS: The synopsis is weak, but I guarantee a million words.