Fantasy: Reappearance of Mountains and Seas

The protagonist has not seen his parents since he was a child. He is later adopted by his current master and lives with his very rich senior brother and his opera singer. But in an accident, the master and senior brother disappeared, and he inexplicably obtained the inheritance of the emperor. He and his friends embarked on a journey to find the master and senior brother. The realm is divided into levels one to nine. Each level has a copper spirit, a silver spirit, and a gold spirit.