Digunai (24 February 1122 – 15 December 1161), also known by his sinicised name Wanyan Liang and his formal title Prince of Hailing (or Hailing Wang), was the fourth emperor of the Jurchen-led Jin dynasty, which ruled northern China between the 12th and 13th centuries. He was the second son of Wanyan Zonggan (完顏宗幹), a son of Aguda (Emperor Taizu) (the founder of the Jin dynasty). He came to power in 1150 after overthrowing and murdering his predecessor, Emperor Xizong, in a coup d'état. During his reign, he moved the Jin capital from Shangjing (present-day Acheng District, Harbin, Heilongjiang Province) to Yanjing (present-day Beijing), and introduced a policy of sinicisation. In 1161, after the Jin dynasty lost the Battle of Caishi against the Southern Song dynasty, Digunai's subordinates rebelled against him and assassinated him. After his death, even though he ruled as an emperor during his lifetime, he was posthumously demoted to the status of a prince – "Prince Yang of Hailing" – in 1162 by his successor, Emperor Shizong. However, in 1181, Emperor Shizong further posthumously demoted him to the status of a commoner, hence he is also known as the "Commoner of Hailing".
Digunai was the second son of Woben (斡本; also known as Wanyan Zonggan 完顏宗幹), a son of Aguda (Emperor Taizu), the founder of the Jin dynasty. Emperor Taizu's brother and successor, Emperor Taizong, started a series of wars between the Jin and Song dynasties. During the reign of Emperor Xizong, who succeeded Emperor Taizong, Wanyan Zonggan was described as the most influential man in the Jin imperial court.
Digunai, who was an army marshal under Emperor Xizong, overthrew the emperor in a coup d'état in 1150 and replaced him. Having seized the throne through illegitimate means, Digunai was suspicious of other members of the Jurchen aristocracy, and, immediately upon taking the throne, started eliminating potential rivals. He ordered the massacre of the descendants of Emperor Taizong, so as to secure the position of the lineage of Emperor Taizu, to which he belonged.
Digunai capitalised on the Jin dynasty's "superior status" vis-à-vis the Song dynasty after its victory over the latter in 1141, and sought to make the Jin dynasty the sole Chinese empire. To legitimise himself as a sinicised ruler, in 1150 he lifted Emperor Taizong's prohibition of wearing Han Chinese dress, and adopted an array of Han Chinese practices and institutions, such as holding of sacrificial ceremonies in the northern and southern suburbs of his capital in 1149 (cf. ceremonies conducted at the Temple of Earth and Temple of Heaven in Beijing during the Ming and Qing dynasties), the use of the imperial carriage in 1151, a system of feudal rights in 1156, and the Song dynasty's shan-hu (山呼) style of court ceremonies in 1157. Digunai also introduced the imperial examination system in 1150 and set up the Imperial Academy in the following year. In his pursuit for greater sinicisation and the desire to acquire the Mandate of Heaven, Digunai moved his imperial court from Shangjing (present-day Acheng District, Harbin, Heilongjiang Province to Yanjing (present-day Beijing) in 1153. In 1157, he ordered the destruction of the imperial palaces in Shangjing.
In contrast to the traditions of the Tang and Song dynasties, which rarely imposed corporal punishment on the members of the society's educated elites, Digunai continued the Khitan and Jurchen tradition of floggings with gusto, sometimes enjoying personally watching his subjects – including chancellors, censors, and a princess – beaten with poles or whips.
Digunai's attempts to conquer the Southern Song dynasty and unify China under the Jin dynasty's rule ended in failure when his fleet was defeated by Song forces at the battles of Tangdao and Caishi in 1161. Many of his officers defected and in some places the people rebelled against him. His subordinates conspired against him and assassinated him on 15 December 1161 in a military camp near the Yangtze River. Digunai's cousin, Wulu, who had led a rebellion against Digunai's rule, was proclaimed the new emperor.
- Father: Woben (斡本), sinicised name Wanyan Zonggan (完顏宗幹)
- Mother: Lady Da (大氏), posthumously honoured as Empress Cixian (慈憲皇后)
- Spouse: Empress Tushan (徒單皇后), bore Alubu
- Lady Da (大氏), Consort Yuan (元妃), bore Wanyan Yuanshou
- Tangkuo Dingge (唐括定哥), Consort Gui (貴妃)
- Lady Xiao (蕭氏), Consort Chen (宸妃)
- Lady Yelü (耶律氏), Consort Li (麗妃)
- Tangkuo Shigge (唐括石哥), Consort Li (麗妃), Tangkuo Dingge's sister, bore Wanyan Shensi'abu
- Pucha Alihu (蒲察阿里虎), Consort Zhao (昭妃)
- Alan (阿懶), Consort Zhao (昭妃)
- Lady Yelü (耶律氏), Consort Rou (柔妃)
- Lady Yelü (耶律氏), Zhaoyuan (昭媛)
- Lady Gao (高氏), Xiuyi (修儀)
- Lady Nan (南氏), Cairen (才人), bore Wanyan Guangyang
- Shigu (什古), Princess Shouning (壽寧縣主), Consort Zhao (昭妃), Wanyan Zongwang's daughter
- Pula (蒲剌), Princess Jingle (靜樂縣主), Consort Shu (淑妃), Wanyan Zongbi's daughter
- Shigu'er (師姑兒), Consort Shu (淑妃), Wanyan Zongjun's daughter
- Shaliguzhen (莎里古真), Princess Huntong (混同郡君), Consort Gui (貴妃)
- Chongjie (重節), Lady of Cheng (郕國夫人), Consort Zhao (昭妃)
- Nailahu (奈剌忽), Consort Yuan (元妃), ex-wife of Zhang Ding'an (張定安)
- Tangkuo Puluhuzhi (唐括蒲魯胡只), Consort Li (麗妃), cousin of Tangkuo Dingge and Tangkuo Shigge
- Pucha Chacha (蒲察叉察), daughter of Princess Qingyi (慶宜公主)
- Alubu (阿魯補), sinicised name Wanyan Guangying (完顏光英), Crown Prince (太子)
- Wanyan Yuanshou (完顏元壽), Prince of Chong (崇王)
- Shensi'abu (矧思阿補), Prince of Su (宿王)
- Wanyan Guangyang (完顏廣陽), Prince of Teng (滕王)
- Henü (合女), Princess of Rong (榮國公主), married Tushan Sila (單術斯剌)
- Daughter, name unknown, married Xiao Yu's (蕭玉) son
- Daughter, name unknown, married Wugulun Yi (烏古論誼)