Duan Yu (1083–1176), courtesy name Heyu, also known by his temple name as the Emperor Xianzong of Dali, was the 16th[1] emperor of the Dali Kingdom, reigning between 1108 and 1147.
Following a family tradition, Duan's father, Duan Zhengchun, abdicated and became a monk in 1108.
Duan succeeded his father as the emperor of Dali and renamed himself Duan Zhengyan (段正嚴).
He abdicated and became a monk in 1147 and was succeeded by his son Duan Zhengxing.
Duan Yu is fictionalized as one of the main characters in the wuxia novel [zh] Demi-Gods and Semi-Devils by Louis Cha.