Ryūjin 龍神 "dragon god" was the ruler of seas and oceans, and described as a dragon capable of changing into human form. He lived in the undersea Ryūgū-jō 龍宮城 "dragon palace castle" built out of red and white coral, from where he controlled the tides with magical tide jewels. Sea turtles, fish, jellyfish, snakes, and other sea creatures are often seen as Ryūjin's servants - Wikipedia. AI video generation.