In Chinese mythology, Fucanglong is traditionally associated with the Earth and underground treasures.
Fucanglong is commonly described in later Chinese dragon lore as an “unknowable” or hidden dragon that guards buried wealth, precious stones, and other treasures beneath the ground. Its association with subterranean riches connects dragons with mountains, minerals, earthquakes, and the hidden forces of the landscape.
Chinese dragon traditions contain many specialized dragon types, and the names and classifications vary among sources. Fucanglong is often placed among the dragon sons or dragon categories found in later popular accounts, rather than treated as one of the Four Symbols of Chinese cosmology.
It is therefore distinct from Qinglong, the Azure Dragon of the east; Yinglong, the winged rain and flood dragon; and Zhulong, the torch or daylight dragon. Those figures have different symbolic roles and should not be treated as interchangeable names.