Sima Yu
Due to Emperor Mu's young age, his mother Empress Dowager Chu became the ruling authority at court and served as regent, although she largely followed the advice of He Chong and Sima Yu the Prince of Kuaiji, who served as co-prime ministers. (Sima Yu took that position after Empress Dowager Chu's father, Chu Pou (), declined) After He Chong's death in 346, his role was taken by Cai Mo.