Yuan Shao in the context of "Guan Yu"

Cao Cao (pronunciation; [tsʰǎʊ tsʰáʊ]; Chinese: 曹操; c. 155 – 15 March 220), courtesy name Mengde, was a Chinese statesman, warlord, and poet who rose to power during the end of the Han dynasty (c. 184–220), ultimately taking effective control of the Han central government. He laid the foundation for the state of Cao Wei (220–265), established by his son and successor Cao Pi, who ended the Eastern Han dynasty and inaugurated the Three Kingdoms period (220–280). Beginning in his own lifetime, a corpus of legends developed around Cao Cao which built upon his talent, his cruelty, and his perceived eccentricities.

Cao Cao began his career as an official under the Han government and held various appointments including that of a district security chief in the capital and the chancellor of a principality. He rose to prominence in the 190s during which he recruited his own followers, formed his own army, and set up a base in Yan Province (covering parts of present-day Henan and Shandong). In 196, he received Emperor Xian, the figurehead Han sovereign who was previously held hostage by other warlords such as Dong Zhuo, Li Jue, and Guo Si. After he established the new imperial capital in Xuchang, Emperor Xian and the central government came under his direct control, but he still paid nominal allegiance to the emperor. Throughout the 190s, Cao Cao actively waged wars in central China against rival warlords such as Lü Bu, Yuan Shu, and Zhang Xiu, eliminating all of them. Following his triumph over the warlord Yuan Shao at the Battle of Guandu in 200, Cao Cao launched a series of campaigns against Yuan Shao's sons and allies over the following seven years, defeated them, and unified much of northern China under his control. In 208, shortly after Emperor Xian appointed him as Imperial Chancellor, he embarked on an expedition to gain a foothold in southern China, but was defeated by the allied forces of the warlords Sun Quan, Liu Bei, and Liu Qi at the decisive Battle of Red Cliffs.

Cao Pi (pronunciation) (c.late 187 – 29 June 226), courtesy name Zihuan, was the first emperor of the state of Cao Wei in the Three Kingdoms period of China. He was the second son of Cao Cao, a warlord who lived in the late Eastern Han dynasty, but the eldest son among all the children born to Cao Cao by his concubine (later wife), Lady Bian. According to some historical records, he was often in the presence of court officials in order to gain their support. He was mostly in charge of defence at the start of his career. After the defeat of Cao Cao's rival Yuan Shao at the Battle of Guandu, he took Yuan Xi's wife, Lady Zhen, as a concubine, but in 221 Lady Zhen died and Guo Nüwang became empress.

On 25 November 220, Cao Pi forced Emperor Xian, the last ruler of the Eastern Han dynasty, to abdicate in his favour, after which on 11 December 220 he proclaimed himself emperor and established the state of Cao Wei. Cao Pi continued the wars against the states of Shu Han and Eastern Wu, founded by his father's rivals Liu Bei and Sun Quan, respectively, but did not make significant territorial gain in the battles. Unlike his father, Cao Pi concentrated most of his efforts on internal administration rather than on waging wars against his rivals. During his reign, he formally established Chen Qun's nine-rank system as the base for civil service nomination, which drew many talents into his government. On the other hand, he drastically reduced the power of princes, stripping off their power to oppose him, but at the same time, rendering them unable to assist the emperor if a crisis arose within the state. After Cao Pi's death, his successor Cao Rui granted him the posthumous name "Emperor Wen" and the temple name "Gaozu".

Lü Bu (pronunciation; died 7 February 199), courtesy name Fengxian, was a Chinese military general, politician, and warlord who lived during the late Eastern Han dynasty of Imperial China. Originally a subordinate of a minor warlord Ding Yuan, he betrayed and murdered Ding Yuan and defected to Dong Zhuo, the warlord who controlled the Han central government in the early 190s. In 192, he turned against Dong Zhuo and killed him after being instigated by Wang Yun and Shisun Rui (士孙瑞), but was later defeated and driven away by Dong Zhuo's followers.

From 192 to early 195, Lü Bu wandered around central and northern China, consecutively seeking shelter under warlords such as Yuan Shu, Yuan Shao, and Zhang Yang. In 194, he managed to take control of Yan Province from the warlord Cao Cao with help from defectors from Cao's side, but Cao took back his territories within two years. In 195, Lü Bu turned against Liu Bei, who had offered him refuge in Xu Province, and seized control of the province from his host. Although he had agreed to an alliance with Yuan Shu earlier, he severed ties with him after Yuan declared himself emperor – treason against Emperor Xian of Han – and joined Cao and others in attacking the pretender. However, in 198, he sided with Yuan Shu again and came under attack by the combined forces of Cao and Liu, resulting in his defeat at the Battle of Xiapi in 199. He was captured and executed by strangulation on Cao's order.

Zhang Xiu (died 207) was a military general and minor warlord who lived during the late Eastern Han dynasty of China. In 197, he clashed with the warlord Cao Cao, who was then the de facto head of the Han central government, at the Battle of Wancheng and subsequent skirmishes. However, in 200, he heeded the suggestion from his adviser Jia Xu and surrendered to Cao Cao, who accepted his surrender and appointed him as a general. Having fought on Cao Cao's side at the decisive Battle of Guandu against a rival warlord Yuan Shao and in the subsequent campaigns against Yuan Shao's heirs, Zhang Xiu made great contributions during his service under Cao Cao. In 207, he died en route to joining Cao Cao on a campaign against the Wuhuan tribes. The Han imperial court honoured with the posthumous title "Marquis Ding".

The Battle of Guandu was fought between the warlords Cao Cao and Yuan Shao in 200 AD in the late Eastern Han dynasty. Cao Cao's decisive victory against Yuan Shao's numerically superior forces marked the turning point in their war. The victory was also the point at which Cao Cao became the dominant power in northern China, leading to the establishment of the state of Cao Wei in the Three Kingdoms period.

Yuan Xi (died c.December 207), courtesy name Xianyi or Xianyong, was a Chinese military general and politician. He was the second son of Yuan Shao, a warlord who controlled much of northern China during the late Eastern Han dynasty. He was executed along with his brother Yuan Shang by Gongsun Kang.

Yuan Xi's wife, Lady Zhen, was taken as a wife by Cao Cao's son, Cao Pi, while Yuan Xi still lived.

Tadun (died 207) was a leader of the Wuhuan tribes during the late Eastern Han dynasty of China. He was an ally of the warlord Yuan Shao and Yuan Shao's son and successor Yuan Shang.