The relationship between the main characters in the Romance of the Three Kingdoms: Cao Cao and Liu Bei were enemies, but they also had a deep cooperative relationship. Cao Cao had once tried to ally with Liu Bei to fight against Sun Quan but ultimately failed. Sun Quan and Liu Bei were also enemies, but they had a complicated relationship. Liu Bei had once asked Sun Quan for help. Guan Yu and Zhang Fei were good friends, but there were also some contradictions between them. Zhuge Liang and Liu Bei: Zhuge Liang is Liu Bei's think tank. The two of them trust each other and rely on each other. Cao Cao and Guan Yu: Cao Cao once regarded Guan Yu as his ally, but Guan Yu betrayed Cao Cao in the Battle of Red Cliff, causing Cao Cao to suffer a crushing defeat. Cao Cao and Zhang Fei: Zhang Fei was once dissatisfied with Cao Cao, but Cao Cao forgave him during the Battle of Red Cliff, which made Zhang Fei more loyal to Cao Cao. Liu Bei and Zhuge Liang: Liu Bei once relied on Zhuge Liang's help, but Zhuge Liang left him when Liu Bei needed him the most, which made Liu Bei very disappointed. Sun Quan and Zhou Yu: Sun Quan and Zhou Yu were once enemies, but in the Battle of Red Cliff, the two became allies and defeated Cao Cao together. Guan Yu and Lu Xun: Guan Yu was once defeated by Sun Quan's navy in the Battle of Red Cliff, but Lu Xun used this opportunity to set fire to the camp and finally defeated Cao Cao. Zhuge Liang and Lu Su: Zhuge Liang and Lu Su were once good friends, but some of Zhuge Liang's actions caused Lu Su's dissatisfaction.