In 401, Duan Ye, apprehensive of Juqu Mengxun's military abilities, demoted him and replaced him with Ma Quan (), but soon believed Juqu Mengxun's false accusations against Ma and executed him. Juqu Mengxun then proposed to Juqu Nancheng that Duan Ye be killed and replaced with Juqu Nancheng—citing Duan Ye's lack of judgment and ability to govern and that with Suo and Ma dead, there would be no one to oppose them if they made a move against Duan Ye. Juqu Nancheng refused, stating that such an action would be unjust.