This Boy Looks Like an Old Monster

There was once a man who had an immortal body. Every time he died, he would be reborn. He has played countless identities, from a rare cultivation wizard in thousands of years to an unknown beggar on the street, the head of the righteous way, the founder of the evil way, the emperor of a certain dynasty, a country doctor, a wine shop, a farmer... It seems that he has experienced all kinds of things in this world, and gradually he feels that it is boring... Until one life, he lived in seclusion in the mountains, returned to his true nature and lived the rest of his life as an ordinary person, when an unknown person appeared out of nowhere and threatened to take his life. What kind of son of fate, time traveler, system... The words are unfamiliar, the description is bizarre, and I have never heard of it. He didn't fight back because he was tired of it...