Why is Cao Cao called Aman?

The explanation of Cao Cao’s nickname Aman should be a change when folk romance stories were spread. Cao Cao’s nickname should be "Aman", which means cute. Later, because "The Romance of the Three Kingdoms" respected Liu and demoted Cao, so The lovely "Aman" became the derogatory "Aman". Pei Songzhi annotated the "The Biography of Cao Man" which records that Cao Cao's "small character Ah Man" was used, which means to deceive. However, Cao Cao had a suspicious character and liked to use tricks, so changing "Man" to "Hou" was very consistent with Cao Cao's character. . In the 72nd chapter of "The Romance of the Three Kingdoms" "Cao Ah Man's troops retreated to Xiegu", Cao Cao was directly called Cao Ah Man. This is an obviously disrespectful name~