Cao Shuang
By Cao Rui's will, his distant cousin Cao Shuang and Sima Yi were regents, but Cao Shuang soon became the dominant figure in the government; while he put on an appearance of respecting Sima Yi, he effectively pushed Sima Yi aside in governing the empire. How Empress Dowager Guo felt about this is not clear, for her political role during Cao Shuang's regency appeared to be minimal – even though Cao Shuang (and later the Simas) all at least formally submitted important matters to her, they decided on those matters without real input from her.