Ch'ih Yu was a monster that had 8 fingers, 8 toes, and a bristly head - apparently a river god since he came forth from the Siang River. He pursued the Yellow Emperor, who finally made a stand against him with an army of bears, tigers, panthers, and other beasts. Finally the Emperor sent a winged dragon, Ying Lung, against him. Ying Lung gathered the waters against Ch'ih Yu, who in turn got wind and rain from Fung Po, a Chinese Aiolos, and so the earth was flooded. Then the Yellow Emperor sent his daughter to stop the rain. After she had done so, Ying Lung pursued and killed Ch'ih Yu.

"According to one story, Ying Lung could not go back to heaven after killing Ch'ih Yu, but had to live underground. So he drew the waters after him and caused drought on earth .... That is, the dragon killer, himself a good dragon, becomes Vritra, the evil dragon, who withholds the waters." Pg 495.

Sometimes Fung Po is also a dragon