Originally, the two of them had assisted Liu Bei together, so why did they want to take the credit? Xu Shu defected to Liu Bei when Liu Bei was in Xinye. In 208, Cao Cao went south and conquered the new territory. When Xu Shu and Zhuge Liang arrived at Changbanpo, they were defeated by Cao Cao. Xu Shu's mother was also captured by Cao Cao. Xu Shu was very filial and had no other choice but to defect to Cao Cao. During the Battle of Chibi, Xu Shu was sent to guard Chang'an to prevent Ma Teng from Xiliang. After the Battle of Chibi, Xu Shu played a good role as a counselor and was deeply loved by Cao Cao. After Cao Pi succeeded to the throne, Xu Shuguan was ranked among the three Dukes. They gave Sima Yi many ideas during Zhuge Liang's Northern Expedition. It is said that he recommended it because in the novel, in order to better set off the character of Zhuge Liang, it is not so much a recommendation as a compliment to Zhuge Liang. Xu Shu had already been highly regarded by Liu Bei before he got Zhuge Liang. How could he be afraid of being robbed of his credit? The specific thing is in the Romance of the Three Kingdoms. It was mentioned

There is also a section introducing Xu Shu in Zizhi Tongjian