Guan Yu and Zhang Fei both had the style of a "guoshi". Guan Yu repaid Cao Cao's kindness while Zhang Fei released Yan Yan out of righteousness. However, Guan Yu was unrelenting and conceited while Zhang Fei was brutal and heartless. These shortcomings resulted in their downfalls. This was not something uncommon." Cheng Yu, an adviser to Cao Cao, also once mentioned that Guan Yu and Zhang Fei were "capable of fighting thousands of enemies". 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. The Australian sinologist Rafe de Crespigny commented: "There are anecdotes describing Zhang Fei as a man of literary tastes who composed verse in the midst of battle, but he is more generally known as arrogant, impetuous and brutal. While Guan Yu was said to be harsh towards men of the gentry but treated his soldiers well, Zhang Fei was courteous towards his betters but cruel to his rank and file. The two men were nonetheless regarded as the finest fighting men of their lifetime." In the historical novel "Romance of the Three Kingdoms", Zhang Fei's physical apperence was describe in the following: eight spans tall(身高八尺), a blunt head of a panther's(豹頭), huge round eyes(環眼), a swallow's heavy jowls, a tiger's beard and a stance of a dashing horse. Zhang Fei's courtesy name is written as 翼德 in Chinese instead of 益德, but both names have the same pronunciation in Mandarin. Zhang Fei was also described to be an alcoholic, and his obsession with alcohol caused his judgment to be affected from time to time. Throughout the novel, Zhang Fei was shown as an exceedingly loyal and formidable warrior, but also a short-tempered man, who often got into trouble more often when he was not on the battlefield. His weapon was a "1.8 "zhang" long steel spear" (), which was also called a "1.8 "zhang" long serpent spear" () because its head was shaped like a snake.