Gao Shun
Around late 197 or early 198, Lü Bu sided with Yuan Shu again and he sent Gao Shun to attack Liu Bei in Xiaopei. Gao Shun defeated Liu Bei, as well as the reinforcements Cao Cao had sent to assist Liu Bei. Later, Cao Cao personally led a campaign against Lü Bu and besieged Xiapi. He wrote a letter to Lü Bu, explaining the benefits of submitting and the consequences of putting up resistance. Lü Bu wanted to surrender, but Chen Gong and the others knew that they had already offended Cao Cao (when they betrayed him earlier), so they urged Lü Bu to change his decision.