a lot of people might find it confusing in why guan yu was with cao cao, but people are forgetting china is a fucking huge country, and there was no cars, cell phones or anything back then. So it was very easy as a soldier to get displaced in battle and stranded in a place you barely even recognize. So you're only real option was either drop by a village and settle down and hope you can find some type of job in that community, or just pick up your sword and work for someone else. Which if i remember my history correctly was Guan Yus situation.
