Geng Zhongming
Kong Youde was illiterate, but was known for his ferocity and martial skills in battle. He was a loyal follower of the semi-independent warlord Mao Wenlong, who operated in Liaodong under nominal Ming supervision. In an effort to unify Ming forces on the northern frontier under a single command structure, general Yuan Chonghuan trapped and executed Mao Wenlong in 1629. Although Yuan had hoped to recruit Mao's followers into the regular Ming army, some including Kong Youde and Geng Zhongming refused to join him. Kong Youde and Geng Zhongming had close relationship, some historical sources indicate that they were sworn brothers, both of them left instead for Dengzhou to work for Sun Yuanhua. While serving in Dengzhou, Kong and Geng were among the officers who learned to use the new European cannons Sun had obtained from Macau.