Is “At the Battle of Yangren, he slew Hua Xiong and routed Dong Zhuo's forces.” true?
attested in history
According to Records of the Three Kingdoms, Book of Wu, Biography of Sun Jian, Sun Jian defeated Dong Zhuo's army at Yangren and killed the commander Hua Xiong; the novel attributes this feat to Guan Yu.
Sun Jian
In official history, he was a brave and resolute Eastern Wu tiger who slew Hua Xiong and defeated Dong Zhuo.