He Yan
Cao Shuang wanted to dominate the Wei government so he used a series of political manoeuvres to consolidate and concentrate power in the hands of himself, his brothers Cao Xi (曹羲) and Cao Xun (曹訓), and their supporters. He heeded the advice of He Yan, Deng Yang and Ding Mi (丁謐), and relocated Empress Dowager Guo (Cao Rui's widow) to Yongning Palace (永寧宮) so that she could not interfere in politics. He also put his brothers in command of the military, promoted his close aides to higher positions in the imperial court, and made changes to the political structure to benefit himself and his clique. Sima Yi tried to stop Cao Shuang but failed to do so. Cao Shuang became increasingly distrustful and wary of Sima Yi. In June or July 247, Sima Yi claimed that he was ill and withdrew from the political scene. At the time, there was a saying in Luoyang which went: "He (Yan), Deng (Yang) and Ding (Mi) create turmoil in the imperial capital."