Records of the Three Kingdoms
Xun You, courtesy name Gongda, was from Yingyin in Yingchuan, a nephew of Xun Yu and older than his uncle. Under He Jin he joined in planning. After Dong Zhuo’s seizure of power he was imprisoned, later returned to the provinces, and then joined Cao Cao. Cao Cao called him a model and took army and state questions to him.
Around Guandu his proposals included striking while Yan Liang and Wen Chou were newly arrived, and using the splits inside Yuan Shao’s camp. Cao Cao later said Xun You had drawn twelve unexpected plans for him. Only some were made public. The rest could not be told at the time. Unlike his uncle, he did not oppose in open court Cao Cao’s advance to Duke of Wei. In 214, on campaign against Sun Quan, he fell ill and died on the road, at fifty-eight. Cao Cao wept for him.
Romance of the Three Kingdoms
In the novel Xun You and Xun Yu are often in the tent together, one closer to the army and one closer to the court. The grain at Guandu and Xu You’s defection are both talked through with him present.
The twelve plans are not turned into twelve chapters. His death on the southern campaign is a passing line, with less space than Guo Jia’s illness.
Reference: Wikipedia · Xun You