Sima Daozi
In 396, Emperor Xiaowu, after offending his favorite concubine Honoured Lady Zhang, was suffocated by her in his sleep. However, with the crown prince being developmentally disabled and with Sima Daozi being foolish and unthinking, no one investigated his death. Crown Prince Dezong took the throne as Emperor An, and Sima Daozi, as uncle, served as regent.