 Yu and the official Cui Guang (崔光), without first consulting Emperor Xuanwu's wife Empress Gao (Gao Zhao's niece), quickly declared Emperor Xuanwu's young son, the crown prince Yuan Xu, emperor (as Emperor Xiaoming).When Empress Gao wanted to put Emperor Xiaoming's mother Consort Hu to death, Yu, Cui, the eunuch Liu Teng (劉騰), and the general Hou Gang (侯剛), protected Consort Hu by hiding her.Yu and Cui soon forced Empress Gao to confer regent authorities on Emperor Xuanwu's uncle Yuan Yong the Prince of Gaoyang and Emperor Xiaowen's cousin Yuan Cheng (元澄) the Prince of Rencheng, and when Gao Zhao subsequently returned to the capital Luoyang from a military campaign against rival Liang Dynasty that Emperor Xuanwu had commissioned, Yu and Yuan Yong ambushed him and put him to death.