Ryujin is a dragon god in Japanese mythology, often associated with the sea and water. He is depicted as a powerful and benevolent deity who controls the tides and storms. Ryujin is typically represented as a large, serpentine dragon, and his palace, Ryugu-jo, is said to be located beneath the ocean. In folklore, Ryujin is known for his ability to transform into a human and is often linked to various legends involving fishermen and sailors. He is also associated with the tako, or octopus, and is believed to possess magical jewels that can control the sea.