Du Yu is the legendary king of ancient Shu. At the end of the Zhou Dynasty, the seven countries became kings, and Du Yu began to be emperor in Shu. In his later years, the flood disaster made Shu people unable to live in peace, so they struggled with water. Turtle spirit inspects the terrain, measures the water potential, drains and vents, floods are unobstructed, and Shu people are safe. Du Yu felt the power of water control, which made the emperor in Master Roshi enlightened him.

Du Yu retired and lived in Xishan. It is said that he became a cuckoo after his death. Every year in the spring ploughing season, the cuckoo sings, which is called "the soul of longing for the emperor" by Shu people, because the cuckoo is called the cuckoo. It is said that he died of shame because of his wife and his soul became a cuckoo. Later, he called the cuckoo "Du Yu".