废帝
In 554, Emperor Fei, angry over Yuwen Tai's execution of the official Yuan Lie () in 553, plotted to have Yuwen killed. However, the news was leaked, and Yuwen deposed him. He selected Yuan Kuo to succeed Emperor Fei (as Emperor Gong). Contemporaneously, Yuwen changed the imperial clan's surname from Yuan back to Tuoba, reversing the change that Emperor Xiaowen ordered in 496.