Another World: I Rely on My Fully Enchanted Shield to Defeat Monsters and Level Up

This is a novel world, a world with distinct levels, a world that can be traveled through a 'window'. The higher you go, the more you can get what you want. Wealth, power, strength, and the perfect opposite sex are all available here. Some people can only survive at the bottom of the world throughout their lives, while some people are born to be the lucky ones at the top. "People say shieldmen are just cannon fodder, but I don't think so." Zhang Yu, a time traveler who came to this world inexplicably, became a shield bearer inexplicably. A career that was criticized as cannon fodder was sublimated by Zhang Yu's new approach. After countless opportunities and choices, will he pursue the mythical legend and return to Earth, or will he continue to live in this crisis-ridden world?