Longevity Martial Arts: Grinding Experience in the Chaotic World

[You have transmigrated, named Gu Sheng, and are a farm boy.] [This is a dynasty in chaos, where demons and monsters lurk and bandits run rampant; as someone at the bottom, you face hellish survival difficulties.] [You decide to lay low.] [You awaken a mastery panel.] [You breathe a sigh of relief, you can start grinding.] [You grind Chopping Wood to Perfect, chopping bones and breaking tendons with ease.] [You grind archery to Perfect, becoming a godlike archer who can hit a louse at a hundred paces.] [You learn the Iron Stone Fist, set foot on the path of a Martial Artist, and grind it to Perfect, with punches as heavy as a million pounds.] …… [You learn the Longevity Eternal Youth True Art, greatly extending your lifespan, giving you more time to grind, and greater hope to lay low.] …… [You grind to the limit, steadily laying low, and one day you suddenly realize, you are invincible.]