司馬穎
After overthrowing Sima Lun, Sima Jiong became the regent—as Sima Ying, who was initially named coregent with him, declined and returned to his stronghold of Yecheng. He became arrogant and extremely controlling, and failed to pay even basic courtesies to Emperor Hui. He also became suspicious of Sima Yong the Prince of Hejian (the grandson of Emperor Hui's great-granduncle Sima Fu the Prince of Anping), because Sima Yong had initially wanted to support Sima Lun, until he saw that Sima Lun's cause was hopeless. Sima Yong knew of Sima Jiong's suspicion, and started a conspiracy; he invited Sima Ai to overthrow Sima Jiong, believing that Sima Ai would fail; his plan was then to, in conjunction with Sima Ying, start a war against Sima Jiong. Once they were victorious, he would depose Emperor Hui and make Sima Ying the emperor, and then serve as Sima Ying's prime minister. In winter 302, Sima Yong declared his rebellion, and Sima Ying soon joined, despite opposition from his strategist Lu Zhi (). Hearing that Sima Ai was part of the conspiracy as well, Sima Jiong made a preemptive strike against Sima Ai, but Sima Ai was prepared and entered the palace to control Emperor Hui. After a street battle, Sima Jiong's forces collapsed, and he was executed.