Guan Hai Wikipedia
Guan Hai was a Yellow Turban rebel general active in the Shandong area during the late Han Dynasty period of Chinese history. In 193, Kong Rong, the governor of Beihai, set out to Duchang (都昌) to quell Yellow Turban Rebellion. In response, Guan led his army to surround Duchang and laid siege to it. Kong sent Taishi Ci to seek help from Liu Bei, who agreed to lend Taishi 3,000 soldiers to relief the siege. Guan's men dispersed after Liu's reinforcements arrived in Duchang.
In Luo Guanzhong's historical novel Romance of the Three Kingdoms, Guan Hai was said to have the strength of ten men and he helped to lead a third insurgence of the Yellow Turbans. In the attack on Kong Rong, Guan Hai challenged Guan Yu to a duel and was slain by his opponent after a few rounds.