Interstellar Wanderer: Unparalleled in the World, I Return to the Old World

Chi, the legendary general who defeated countless forces, retired for some reason and became an interstellar wanderer, wandering around the universe. One day, his childhood sweetheart sent him a message asking for help. Let him go to an old world that is remote, backward, and not yet synchronized with the information of the universe to help. I thought it was just wandering around anyway, so why not take a trip to the old world and help out on the way. He originally thought it would be an easy journey of chopping melons and vegetables, but what he didn't expect was that not only did he encounter a plane crash at the beginning, but he also soon discovered that a secret experiment about the fate of the universe was being conducted on this planet...