Hachidai Ryūō, the "Eight Great Dragon Kings," refers to a group of dragon deities inherited from Buddhist cosmology, particularly the Lotus Sutra, where they appear as protectors of the Dharma. In Japanese tradition they are closely associated with water, rain, and weather, often venerated at shrines and temples near lakes, rivers, and mountains as guardians who influence rainfall and safeguard against drought or flooding. Devotees have historically prayed to them for favorable weather and protection of agricultural water sources, though such petitions reflect folk belief rather than doctrinal guarantee.