Chi You is also the god of rain, and a descendant of Shennong, the inventor of agriculture. His appearance is half giant, half bull, with the front of his head covered with iron.
Along with and , Chi You is a deity in Hmong mythology, Chi You was the mythical leader of the , king of , and once a follower of Yan Di. When Huang Di subdued Yan Di, Chi You was weary of the suppression and conspired with Yan Liang, another deity. Soon, Huang Di and Chi You clashed in the Battle of Zhuolu.
According to Chinese legends, Chi You and his people rebelled against Yellow Emperor at Zhuolu plains. Both sides used magical powers, but Chi You had the advantage because his troops were armed with forged swords and halberds. Using his power , Chi You covered the battle field in thick fog. Only with the help of a magical compass chariot could Huang Di's troops could find their way through the mist. He also used his daughter Nü Ba, the Goddess of Drought, to harm Chi You's troops. Later on, Chi You suffered more defeats and was captured. Only Ying Long, the winged dragon, being a brave servant of Huang Di, dared to slay him. Chi You's chains were transformed into acorn trees, while Ying Long was cursed to remain on earth forever.
According to Chinese legend, the people under Chiyou were defeated at Zhuolu by the military unification of Huang Di and Yandi, leaders of the Huaxia tribe as they struggled for supremacy of the Yellow River valley. The compass was believed to be the crucial reason of Huaxia's victory. The battle, believed to be taken place in the 27th century BC, was fought under heavy fog as Huaxia was able to match against Miao with the compass. After the loss, the original tribe split into two smaller splinter tribes, the Miao and the . Miao continuously moving southwest and Li southeast as the Huaxia race, now known as Han Chinese race, expanding southwards. During the course of Chinese history, they were regarded as "barbarians" by the increasingly technologically and culturally advanced Han Chinese. Some fragments of the races were assimilated into the Chinese during .
Yet, in other versions, the people of Jiuli fragmented in 3 different directions. It is said Chiyou had 3 sons, and after the fall of Jiuli, his oldest son led some people south, his middle son led some people north, and his youngest son remained in Zhuolu and assimilated into the Huaxia culture. Those who were led to the south established the San-Miao nation. Perhaps due to this splitting into multiple groups, many Far Eastern people regard Chiyou as their ancestors, and by the same token, many question the ethnicity of Chiyou as exclusively Hmong or otherwise. In some circles of thought, the Koreans also regard Chiyou as an ethnic ancestor. Chiyou is also regarded as one of China's forefathers alongside the ethnic Han ancestors, Huangdi and Yandi.
Other mythology states that Chi You had 81 brothers, and was a grotesque looking creature: he had six arms, four eyes, the head and hooves resembled an ox and his head was made of metal . He only ate stones and pebbles; therefore his teeth were almost unbreakable. One of his achievements was the first use of metal weapons in warfare. He is said to have forged the first swords from bronze or copper. He was violent and no one could defeat him.
Across the Eastern Asia, many people had worshipped Chi You as the war guardian deity. According to Chinese history record ''Records of the Grand Historian'', at Chi You's shrine before the last battle against Xiang Yu and won. Joseon Navy Admiral Yi Sun-sin also worshipped Chi Woo, and he has never lost a battle, and thus deemed a hero in the war against Toyotomi Hideyoshi's army during
the during 1592-1598.
Figure in Hwandan Gogi
According to the controversial Korean mythology book ''Hwandan Gogi'' which was first published in 1979 and which says it was compiled and edited by Gye Yeonsoo in 1911 , 'Chiwoo' was 14th Emperor, named Jaoji-Hwanwoong, of the Empire of Baedal, which was to be succeeded by Go-Joseon, as the book says. He ruled the Empire during 109 years. According to these accounts, Emperor Chi-Woo succeeded Emperor Sawara of Baedalguk, the 13th ruler of Baedalguk, at around 41 years of age and is seen today as a great hero who expanded the territory of his empire tremendously, which was said to have reached the Shandong Peninsula area at its greatest extent. During his reign, he was said to have highly advanced the technology of his empire as well. Baedal was said to have possessed catapults, flaming arrows, and bronze swords starting from the reign of Emperor Chi-Woo, while its neighbors were still in the stone age. Chi-Woo was said to have reigned for 109 years, and died at the age of 151. He was good at making weapons such as an arrow, a bow, a spear, an amor and a helmet, and he also could deal with copper and iron. In addition, he united 12 feudal states, and was not defeated for about 70 wars. The books claims that Chiwoo's grave was in present Shandong province of China, and that in every July, the red flag, the symbol of Chi You's army appeared on top of his grave.
According to the same accounts, when Chiwoo became an emperor of Baedalguk, Yoomang , who was a descendant of Shennong, was a king in the nation of Shennong. At that time, the nation of Shennong became powerful because the population had increased so much. Emperor Chiwoo felt surrounded by threats and decided to attack the nation of Shennong, and prepared bows, arrows, spears and swords. Emperor Chiwoo assembled his army of nine grand generals and 81 adjunt generals in , and conquered the troops of Yoomang at Kuhon. Thereafter, Emperor Huangdi heard that Emperor Chiwoo was governing the land of Shennong. Huangdi assembled his troops, and waged war on Emperor Chiwoo and Baedal more than 70 times during ten years. It is said that Emperor Chiwoo defeated Emperor Huangdi in all of the battles except one.
Chiwoo, also called "Chiwoo Cheonwang" in Korea, is the mascot of the Red Devils, the supporters' group to the South Korea national football team. The manhwa ''Heavenly Executioner Chi Woo'' is partly based on the legends about Emperor Chi Woo.