Later, he was changed to Yunchang, a native of Hedong (now Yuncheng, Shanxi), and a famous soldier in the late Eastern Han Dynasty. In his early years, he fled from his hometown to Zhuo Jun, a secluded state, for committing crimes. In the first year of Zhong Ping (184), Liu Bei, a relative of the Han clan, organized a volunteer army in Zhuoxian to fight against the Yellow Scarf Army, and Guan Yu and Zhang Fei were among them. After Liu Bei was transferred to many official posts, he defected to his former classmate Gongsun Zan, and was named the Plain Country. Guan Yu and Zhang Fei were appointed as other horses and enfeoffed different departments. Three people are brothers and often sleep in the same bed. After Liu Bei was seated, Guan and Zhang took good care of him. In the first year of Xingping (194), Cao Cao attacked Tao Qian and wanted to take Xuzhou. Tao Qian turned to Liu Bei for help. Liu Bei and Guan Yu led more than a thousand people to the rescue. Cao Caobing retreated, and under the repeated concessions of Tao Qian and others, Liu Bei led Xuzhou to graze. In the first year of Jian 'an (196), Liu Bei was attacked by Yuan Shu and Lu Bu and lost to Xuzhou. Guan Yu followed Liu Bei to Cao Cao. In the third year of Jian 'an (198), Liu Bei and Cao Cao captured Lu Bu in Xiapi and captured Xuzhou. Guan Yu and Liu Bei followed Cao Cao's troops back to Xuchang, and Cao Cao appointed Che Zhou as the secretariat of Xuzhou. After Yuan Shu went north to Yuan Shao, Liu Bei was ordered by Cao Cao to intercept Yuan Shu in Xuzhou. Liu Bei took the opportunity to attack and kill Che Zhou, ordered Guan Yu to keep Pi, led Xuzhou, and Liu Bei returned to Xiaopei.