From the introduction: The Great Thousand Worlds you have currently entered is a vast, endless place. Many clans live here. The Northern Spiritual Realm, home to the protagonist, is just like a tiny speck of sand within an ocean. It is an insignificant place. The Great Thousand Worlds is made up of ten super continents, each many times larger than entire worlds. Moreover, the Great Thousand Worlds interweaves with numerous worlds. However, those worlds could only be called Lower Planes. This is because this world is at a higher level than those worlds.