The leader of the black cavalry is Liu Yongfu. He was originally from Guangxi. He was born in a poor family and could only make a living by farming. Natural and man-made disasters, because of successive natural disasters, led to the failure of the banker, and then Liu Yongfu went everywhere. Unfortunately, natural disasters continue, and he is hungry. Later, Liu Yongfu's parents and uncle starved to death. In order to bury his family, Liu Yongfu had to sell his property. Later, Liu Yongfu took part in the Heaven and Earth Uprising and took refuge in Wu Yazhong. Liu Yongfu helped Wu Yazhong destroy Huang Sihong. Therefore, he won the appreciation and trust of Wu Yazhong and was awarded the "vanguard of the enemy in the left front", so Liu Yongfu began to have his own army-"Black Flag Army".
Later, when Wu Yazhong was besieged by the Qing army, Liu Yongfu saw something bad and led the "black cavalry" to flee to Vietnam. Liu Yongfu, who fled to Vietnam, has no strength to compete with the Vietnamese government. He chose to win over, so the "black cavalry" became the Vietnamese army. Later, Liu Yongfu cooperated with the Vietnamese government many times to crack down on thieves and helped the Vietnamese government destroy Wu Yazhong. Later, the Vietnamese government granted Liu Yongfu land. Liu Yongfu and the Black Flag Army, who had been wandering for many years, finally gained a foothold in Vietnam and bid farewell to the days when they had no fixed abode. The Black Flag Army is also growing, from the initial 200 people to more than 2,000 people, and has become a military force that cannot be ignored on the Vietnamese border.