(Also Lung-wang)
"Dragon Kings"
In Chinese Mythology, Long-wang were the dragon kings and mythical figures in Taoism. They were ruled either by Yuanshi Tian-Zong (the Celestial Venerable of the Primordial Beginning) or Yu Huang (the Jade Emperor), to whom they reported once per year. The dragon kings had jurisdiction over funerals, rain, and to a lesser extent, wells and water-ways. They were powerful and tended to be generous to humans, who might call for a Long-wang's help during a botched funeral ceremony to prevent misfortune for the attending relations. During draughts they were invoked to bring rain and oddly, if the request was not granted within a certain time period, a representation of the Long-wang would be left somewhere unpleasant to "force" the dragon into providing water, at which time a celebration would be held in its honor. They could be controlled or driven away with the wang plant, five-colored silk thread, wax, iron, or centipedes.
Like all Chinese dragons, Long-wang had the head of a camel, the horns of a stag, the eyes of a demon, feet of a tiger, and sometimes the ears of a cow. There was a hump on the top of the head that allowed flight, even without the presence of wings. They could assume human form, and had a general shape-changing ability that could be utilized during periods of intense concentration or anger. They regularly shed their skins, bones and teeth. There were different types of Long-wang: T'ien Lung, the Celestial Dragon and the guardian of the gods, Fu Tsang Lung, the Dragon of Hidden Treasure, the dragon kings of the five cardinal points and the dragon kings of the ocean.
There were four dragon brothers that made up the oceanic Long-wang: Ao Kuang, Ao Jun, Ao Shun, and Ao Ch'in. Each watched over one of the four seas, aided by armies of marine creatures that also made up the court of the dragons’ undersea dwellings called Crystal Palaces, which were believed to be made from the finest crystals. The four dragons were invoked to produce the rain each year, being told how much was needed and where it was to fall on the August Personage of Jade. Each brother carried a very valuable pearl in his throat.
Note: Chi Lung Wang was an extremely wise and honorable ancient Chinese dragon who was sometimes considered the fifth of the dragon-brother kings. He was closely linked with the four Long-wang and associated with water as well as the usage of water pumps.
Sources:
http://starfyre13.tripod.com/draconis.htm
http://www.pantheon.org/articles/l/long-wang.html
http://www.polenth.demon.co.uk/myth/favmyth.html#chi
http://www.igolddragon.com/chinesedragons.htm
Note: There is some confusion over whether Long-wang was a singular deity, only made up of the four oceanic dragon brothers (sometimes five) or if there were many categories of dragon king. In this, I operate on the latter assumption.