A Free and Easy Swordsman

With a three-foot green blade in hand, no one can be killed. He was originally a child of a big family, but he was forced to live on the street due to family disputes. He accidentally obtained a peerless sword and embarked on an unusual path. I want to live a happy life, but people in the world deceive me in every possible way. In this case, I will kill it until the earth falls apart.