Records of the Three Kingdoms
Xu Huang, courtesy name Gongming, was from Yang in Hedong. He began under the chariot general Yang Feng. While escorting Emperor Xian east he met Cao Cao and later joined him. At Guandu he and Shi Huan intercepted Yuan Shao’s grain carts and burned the supplies. He fought often in the north and in Guanzhong after that.
In 219 Guan Yu besieged Cao Ren at Fan and Yu Jin surrendered. Xu Huang was sent to relieve the city. Before Cao Cao’s main reinforcement arrived he refused a close assault and camped farther out. When the armies joined he broke Guan Yu’s siege lines and shot a letter into the city for Cao Ren. Guan Yu withdrew. Cao Cao walked the field, praised the handling of the troops, and compared Xu Huang to Zhou Yafu of the early Han. That praise is in the biography. Xu Huang died of illness in 227.
Romance of the Three Kingdoms
In the novel Xu Huang is one of the five elite generals and fights with a great axe. At Fan he arrives with the relief, denounces Guan Yu in front of the lines, and the armies clash.
The book keeps the credit for raising the siege and adds a scene of old acquaintance with Guan Yu. The axe is remembered before the grain road and the camps of the histories.
Reference: Wikipedia · Xu Huang