During the Xingping era of Emperor Xian of Han, a children's rhyme spread in Wu: "Golden chariot, colorful ears, open Changmen gate, the emperor appears."
More than two decades later, a yellow dragon and a phoenix appeared in the skies over Xiakou and Wuchang. Since both locations were under Sun Quan's rule, his ministers declared these omens auspicious and urged him to become emperor. Cao Cao's son Cao Pi and Liu Bei had already declared themselves emperors, founding the Wei and Han kingdoms respectively.
Sun Quan, persuaded by his ministers, decided to also become emperor. At the southern outskirts of his capital Wuchang, he slaughtered cattle and sheep, ascended the altar to offer sacrifices to the gods, and formally took the imperial throne, styling himself the Great Emperor of Wu. At that time, Zhuge Liang, the Chancellor of the Han Kingdom, was pursuing a strategy of allying with Wu to resist Wei. Upon hearing that Sun Quan had declared himself emperor, he sent an envoy to offer congratulations and propose a formal alliance. Sun Quan, considering that Wei was too powerful for Wu to confront alone, agreed to the union.
The covenant between the two kingdoms declared: "Heaven has sent down calamities, throwing the state into chaos with treacherous ministers causing unrest—this began with Dong Zhuo and ended with Cao Cao. Both Dong Zhuo and Cao Cao were utterly ruthless, tearing the realm apart and leaving the people destitute. Now, our Wu and Han kingdoms renew our alliance, pledging never to invade each other and to unite our efforts against Wei..."
Shortly after Sun Quan established the Kingdom of Wu, he moved the capital to Jianye and appointed Grand General Lu Xun to assist Crown Prince Sun Deng in guarding Wuchang.
Later, the idiom "Extreme Wickedness" came to describe the utmost cruelty and evil.
Source: *Records of the Three Kingdoms*, Book of Wu, "Biography of Sun Quan"
Meaning of the Idiom: Later, the Chinese idiom "穷凶极恶" came to describe the utmost cruelty and evil.