Princess Tamatori steals Ryūjin's jewel, by Utagawa Kuniyoshi.Ryūjin or Ryōjin (龍神?; dragon god), also known as Ōwatatsumi, was the tutelary deity of the sea in Japanese mythology. This Japanese dragon symbolized the power of the ocean, had a large mouth, and was able to transform into a human shape. Ryūjin lived in Ryūgū-jō, his palace under the sea built out of red and white coral, from where he controlled the tides with magical tide jewels. Sea turtles, fish and jellyfish are often depicted as Ryūjin's servants. Ryūjin was also the father of the beautiful goddess Otohime who married the hunter prince Hoori.
King Wada has the ability to transform into a Water Dragon. He was cursed by the Fox Rods and entered a mad rage, killing all who drew near. Once his wife Otohime becomes the ruler of the Dragonians, she gains the ability to transform into a Water Dragon.