Guo Tu
When Cao Cao was retreating across the Yellow River, Yuan Tan requested new equipment and additional troops from Yuan Shang so he could catch Cao Cao mid-river. Doubtful of his elder brother's intentions, Yuan Shang granted neither. Yuan Tan's advisors Guo Tu and Xin Ping added fuel to the fire by suggesting it was Shen Pei who made Yuan Shao send Yuan Tan away to be adopted by his uncle, causing a furious Yuan Tan turned his army to attack Yuan Shang and Shen Pei in Ye. Yuan Tan was defeated and fled to Nanpi, while Cao Cao returned to his capital Xu City apparently unmolested.