모용수
In 369, when Huan Wen launched a major attack against Former Yan, the Former Yan emperor Murong Wei and regent Murong Ping panicked and sought assistance from Former Qin, promising to cede the Luoyang region to Former Qin if it rendered assistance. Most Former Qin officials suggested a refusal, but Wang reminded Fu Jiān that if Huan conquered Former Yan and added its territory to Jin's, Former Qin would not be able to stand. Fu Jiān therefore sent a force commanded by Shi Yue (石越) to relieve Former Yan, whose general Murong Chui defeated Huan, with Shi's assistance. However, Former Yan refused to cede Luoyang, and Fu Jiān commissioned Wang to lead a 60,000-men force against Former Yan later that year. Wang's campaign seemed even more promising after Murong Chui, fearful of Murong Ping's jealousy and the emperor Murong Wei's mother Empress Dowager Kezuhun's hatred toward him, defected to Former Qin. Fu Jiān greeted Murong Chui with great honors, but Wang distrusted Murong Chui.