Guo Jia
However, the "Fu Zi" gave a completely different account of Guo's advice to Cao Cao on how to handle Liu Bei. Guo Jia told Cao Cao, "Liu Bei has great ambitions and has won the hearts of many people. Zhang Fei and Guan Yu are formidable fighters and they have pledged to serve him with their lives. From what I observe, Liu Bei will never truly submit to anyone, and his intentions are unclear. The people in the past once said, 'If you let the enemy off today, they will become a threat to you for a long time.' You should settle (Liu Bei) soon." At the time, Cao Cao was using Emperor Xian as a figurehead to command respect and had attracted many heroes to serve under him so he did not heed Guo Jia's advice. When Cao Cao later sent Liu Bei with an army to attack Yuan Shu, Guo Jia and Cheng Yu warned Cao, "Liu Bei will rebel if you let him go!" By then, Liu Bei had already left and he really did rebel against Cao Cao as he later seized control of Xu Province from Che Zhou, the provincial governor appointed by Cao Cao. Cao Cao regretted not following Guo Jia's advice.