Cao Rui (in Chinese: 曹叡), also known as Emperor Ming (in Chinese: 明帝), is one of the major characters in the 14th-century Chinese classic novel Romance of the Three Kingdoms by the late Luo Guanzhong, and its multiple adaptations. He is Cao Pi and Lady Zhen's son and the second emperor of Wei.
Cao Rui is often portrayed as a smart and gentle man, he was said to be a incompetent ruler who has learned many knowledge like his father. They are came across a doe and a fawn. After Cao Pi dies, Cao Rui remembering his mother is already passed away, broke out in tears and didn't want to shoot the fawn. Cao Pi was moved and dropped his bow and arrows.
Although Cao Rui was only 20 years old, when he ruled on his own when he ascended to the throne of Wei, he was placed under the regency of his stepmother, Lady Guo. He fought against the Wu kingdom, when they are invaded Wei, led by Lu Xun's commander-in-chief, he fought with Wu and defeated them with the help of General Man Chong and General Zhang Qiu. When Lady Guo died, he completely controlled Wei.
However, he led his army to participate in the election campaign of Gongsun Yuan. But before he won, he died of illness and was inherited by his adopted son Cao Fang. At that time, he was only 9 years old, so Cao Rui appointed a weak Cao Shuang and a powerful and awkward Sima Yi - a fatal mistake because Sima Yi's grandson and sons controlled the Wei government and seized the throne.
- During his reign, he was known for being able to entrust the right people for the most appropriate positions, but it was argued that his lavish spending in palaces drained Wei's treasury.