The Legend of the Sword Girl with a Negative Son

At the end of the Qing Dynasty, foreign guns and cannons broke the peace in the East and shocked the Chinese martial arts world. The era of swords is about to pass, and an era of great changes is coming. If you are a swordsman, you have studied with your master in the mountains and forests for twenty years and have become the best swordsman in the world. However, when you come out of the mountain, you find that no one in the world uses swords anymore. With this sword in your hand, where should you go?