Records of the Three Kingdoms
Xu Chu, courtesy name Zhongkang, was from Qiao in Qiao, Cao Cao’s own district. He gathered the clan behind a wall, later brought them to Cao Cao, and was made a palace guard. The army called him Tiger Fool because of his strength. After Dian Wei he was the most famous guard at Cao Cao’s side.
At Tong Pass in 211 Ma Chao’s attack was very sharp. Xu Chu covered Cao Cao onto the boat and across the river. Xu Chu lived into Cao Pi’s reign. The biography does not fix the year of his death.
Romance of the Three Kingdoms
The novel has him strip and duel Ma Chao to a draw. The histories describe a guard and a withdrawal, not a fair fight in front of the lines.
The nickname Tiger Fool is easy to turn into a type. The book uses him for the strength beside Cao Cao, in the years after Dian Wei.
Reference: Wikipedia · Xu Chu