王世充
Cheng Yaojin became a prisoner-of-war after Li Mi was defeated by Wang Shichong. Although Wang Shichong treated him generously, he still felt disgruntled with Wang's ways and complained about Wang to his former colleague, Qin Qiong. When Wang Shichong was at war with the Tang faction led by Li Yuan at Jiuqu (), Cheng Yaojin and Qin Qiong defected to the Tang side on the battlefield along with their followers. Wang Shichong was afraid of them so he did not order his men to stop them.