Yuan Shao
When Cao Cao and Yuan Shao clashed at the Battle of Guandu in 200, Yuan sent Liu Bei to contact Liu Pi (), a Yellow Turban rebel chief in Runan (), and assist Liu Pi in attacking the imperial capital Xu while Cao Cao was away at Guandu. Guan Yu reunited with Liu Bei around this time. Liu Bei and Liu Pi were defeated by Cao Cao's general Cao Ren, after which Liu Bei returned to Yuan Shao. Liu Bei secretly planned to leave Yuan Shao, so he pretended to persuade Yuan Shao to form an alliance with Liu Biao, the Governor of Jing Province. Yuan Shao sent Liu Bei to contact another rebel leader, Gong Du (), in Runan, where they gathered a few thousand soldiers. Cao Cao turned back and attacked Runan after scoring a decisive victory over Yuan Shao at Guandu, and he defeated Liu Bei in Runan. Liu Bei fled south and found shelter under Liu Biao, who put him in charge of Xinye at the northern border of Jing Province. Guan Yu followed Liu Bei to Xinye.