During the Three Kingdoms period, Cao Cao, known for his suspicious nature, wanted to project a majestic image when meeting an envoy from the Xiongnu. He arranged for the impressive Cui Jigui to impersonate him during the reception.

Cao Cao himself, disguised as a warrior, stood by the bed holding a knife.

After the meeting, Cao Cao secretly sent someone to ask the Xiongnu envoy about his impression of the King of Wei. The envoy responded, 'The man holding the knife by the bed is the true hero.'

This story illustrates the idea of having someone act as a proxy or stand-in, especially to convey a particular image or fulfill a role.