The four Dragon Kings are, in Chinese mythology, the divine rulers of the four seas (each sea corresponds to one of the cardinal directions). Although Dragon Kings appear in their true forms as dragons, they have the ability to shape shift into human form. The Dragon Kings live in crystal palaces, guarded by shrimp soldiers and crab generals.

Besides ruling over the aquatic life, the Dragon Kings also manipulate clouds and rain. When enraged, they can flood cities. According to The Short Stories on the Tang People, the Qian Tang Dragon King did just that when he found out his niece had been abused by her husband. Qian Tang also ate the abusive husband.
The Dragon King of the Eastern Sea (Donghai) is said to have the largest territory.

Dragon Kings appeared commonly in literature. Detailed descriptions were given of the finery of their crystal palaces. In the Chinese classical novel Journey to the West, a Dragon King is one of the main characters in the tenth chapter.