Cheng Yu, an adviser to Cao Cao, also once mentioned that Guan Yu and Zhang Fei were "capable of fighting ten thousand of enemies" (萬人敵). In the main text of Zhang Fei's biography, Chen Shou wrote that Zhang Fei respected virtuous persons and detested those of vile character. Liu Bei had constantly warned Zhang Fei about his barbaric behaviour as he once told the latter: "You have dealt out far too excessive punishments. You often flog your men, who are actually the ones who will carry out your orders. Your behaviour will get you into trouble." Zhang Fei still did not change his ways.(初，飛雄壯威猛，亞於關羽，魏謀臣程昱等咸稱羽、飛萬人之敵也。羽善待卒伍而驕於士大夫，飛愛敬君子而不恤小人。 ... 先主常戒之曰：「卿刑殺旣過差，又日鞭檛健兒，而令在左右，此取禍之道也。」飛猶不悛。) Sanguozhi vol. 36.
