Inadvertently Invincible - Chapter 6: Shredder Muscle Sword

I found a girl of unknown origin outside; she claims to be a time traveler from a post-apocalyptic era.Great calamity is imminent, with abominations spreading across the land, human civilization annihilated, and even the world itself shattering, all beyond redemption.As for myself,I am considering how to confine this beautiful girl, who has temporarily lost her powers, within my home.

[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.]

A man betrayed by a comrade dies a wretched death as a third rate swordsman. His existence, his life, his emotions are all a nuisance in the eyes of society. But wait… What’s this green skin? Reincarnated as a goblin? Wait, I went back in time as well?

In the Solarian Empire, people were divided by their blood. The nobles enjoyed their life in wealth, with fine wine and amazing food. They reigned supreme over the commoners. The only reason they were able to do this was that they had knowledge of the most powerful force in the world - magic. The nobles controlled their knowledge from easily going to commoners, making it harder for them to learn magic.

Leo, a young orphan in Solaria, had an incredibly powerful affinity for magic. He didn't even know about it because he could never learn magic- he was too poor to try and learn from any magic academies. He was just trying to survive the streets of Solhaven until he found the lost tome of the Arcane Emperor.

"I can beat a 7th Circle Mage."

"Wow! You must have trained for many decades. How old are you?"

"17."

"..."

The world was going to be turned upside down.