The protagonist does not upgrade through combat, but through "fishing", a seemingly leisurely method, to fish for treasures, techniques, and even "concepts" and "creatures" from the "long river" of the universe. His pond is the hub connecting all realms.
World view: There are countless planes, such as the world of immortality, the world of cyberpunk, the battlefield of gods and demons, the plane of Paper Man animation, etc. These worlds join together into a long river called "Origin".
