Courtesy name Yunchang. Guan Yu is an oath brother to Liu Bei and Zhang Fei, him being the second oldest. He is one of the most powerful warriors of his era, rivaling the likes of Lü Bu and Sun Ce. When he was temporarily serving under Cao Cao, Guan Yu played a vital role as his bodyguard and also briefly tipped the balance of power on the battlefield.
Guan Yu is a man of honor and righteousness, as well as a devoted follower of his oath brother Liu Bei. He will punish a man for his wrong, but also respects him for his right. Unfortunately this idealism makes him vulnerable to manipulation, either by friend or foe.