Guan Yu ([kwán ỳ] ⓘ; d. January or February 220[a]), courtesy name Yunchang, was a Chinese military general serving under the warlord Liu Bei during the late Eastern Han dynasty of China.

Through generations of storytelling, culminating in the 14th-century historical novel Romance of the Three Kingdoms, his deeds and moral qualities have been emphasized immensely, making Guan Yu one of East Asia's most popular paradigms of loyalty and righteousness.

During the fifth century, Pei Songzhi annotated the Sanguozhi by incorporating information from other sources to Chen Shou's original work and adding his personal comments.

In Romance of the Three Kingdoms, Guan Yu's weapon was a guandao named Green Dragon Crescent Blade, which resembled a glaive and was said to weigh 82 catties (about 49 kg or 108 lbs).

When the Yellow Turban Rebellion broke out in the 180s, Guan Yu and Zhang Fei joined a volunteer militia formed by Liu Bei, and they assisted a colonel Zou Jing in suppressing the revolt.

[10] Zhang Fei and Guan Yu protected Liu Bei whenever there were large crowds of people and also stood guard beside him when he sat down at meetings all day long.

[Sanguozhi 4] Guan Yu was noted for his kindness towards his soldiers and fealty to Liu Bei akin to family, but had no respect for the gentry and treated them without courtesy.

[Sanguozhi others 11] After seizing and pacifying the various commanderies in southern Jing Province, Liu Bei appointed Guan Yu as the Administrator (太守) of Xiangyang and General Who Defeats Bandits (盪寇將軍), and ordered him to station at the north of the Yangtze River.

[Sanguozhi others 13] Lu Su (the overall commander of Sun Quan's forces in Jing Province) later invited Guan Yu to attend a meeting to settle the territorial dispute.

When they met again at Fancheng, Xu Huang gave an order to his men: "Whoever takes Guan Yu's head will be rewarded with 1,000 jin of gold."

[Sanguozhi others 16] When Guan Yu embarked on the Fancheng campaign, he left Mi Fang and Shi Ren behind to defend his key bases in Jing Province – Nan Commandery and Gong'an.

When Sun Quan invaded Jing Province, Lü Meng showed understanding towards Mi Fang and successfully induced him into surrendering while Yu Fan also persuaded Shi Ren to give up resistance.

With the exceptions of the northwest, Liu Bei's territories in Jing Province fell under Sun Quan's control after the surrenders of Mi Fang and Shi Ren.

[Sanguozhi zhu 7] Pei Songzhi commented on the Dianlue account as follows: Although Liu Bei and Sun Quan appeared to get along harmoniously, they were actually distrustful of each other.

When Sun Quan later attacked Guan Yu, he dispatched his forces secretly, as mentioned in Lü Meng's biography: '[...] elite soldiers hid in vessels disguised as civilian and merchant ships.'

Guan Yu knew that he had been isolated so he withdrew to Maicheng (麥城; in present-day Dangyang, Hubei) and headed west to Zhang District (漳鄉), where his remaining men deserted him and surrendered to the enemy.

Later, when Liu Bei reached Xiakou (after his defeat at the Battle of Changban), Guan Yu complained, "If you heeded my advice during the hunting expedition in Xu, we wouldn't end up in this troubling situation."

[Sanguozhi zhu 16] In 1719, the Kangxi Emperor of the Qing dynasty awarded the hereditary title "Wujing Boshi" (五經博士; "Professor of the Five Classics") to Guan Yu's descendants living in Luoyang.

"[Sanguozhi 27] Guan Yu was deified as early as the Sui dynasty (581–618), and is still worshipped today as a bodhisattva in Buddhist tradition and as a guardian deity in Chinese folk religion and Taoism.

Martial temples and shrines dedicated exclusively to Guan Yu can be found across mainland China, Hong Kong, Macau, Taiwan, and other places with Chinese influence such as Vietnam, South Korea and Japan.

This title was expanded to "Guan the Holy Great Emperor; God of War Manifesting Benevolence, Bravery and Prestige; Protector of the Country and Defender of the People; Proud and Honest Supporter of Peace and Reconciliation; Promoter of Morality, Loyalty and Righteousness" (仁勇威顯護國保民精誠綏靖翊贊宣德忠義神武關聖大帝), a total of 24 Chinese characters, by the mid-19th century.

In 1866, the Ten Completions Society (Shiquanhui 十全會) was established to propagate the messages of Guandi and promote the charitable work his spirit had ordered to perform.

In Hong Kong, Guan Yu is often referred to as "Yi Gor" (二哥; Cantonese for "second elder brother") for he was second to Liu Bei in their fictional sworn brotherhood.

Guan Yu is also worshipped by Chinese businessmen in Shanxi, Hong Kong, Macau and Southeast Asia as an alternative wealth god, since he is perceived to bless the upright and protect them from the wicked.

Apart from general worship, Guan Yu is also commemorated in China with colossal statues such as the 1,320-tonne sculpture in Jingzhou City, Hubei Province, standing at 58 metres.

Emperor Huizong then bestowed upon Guan Yu the title "Immortal of Chongning" (崇寧真君; Chóngníng Zhēnjūn), formally introducing the latter as a deity into Taoism.

[citation needed] According to Buddhist legends, in 592, Guan Yu manifested himself one night before the Chan master Zhiyi, the founder of the Tiantai school of Buddhism, along with a retinue of spiritual beings.

Other non-Koei titles in which he also appears include: Total War: Three Kingdoms;[21] Puzzle & Dragons;[22] Sango Fighter; Destiny of an Emperor; and Atlantica Online.

[citation needed] The hero Jiang Jun that appears in an add-on for the game For Honor, developed by Ubisoft Montreal, is heavily based on Guan Yu.

[26] "To the Chinese audience familiar with the famous tale of Lord Guan, there could have been no doubt of Deng's determination to push ahead with radical price reforms.