Yuwen Shu
After Emperor Yang took the throne, Yuwen Shu, as one of his confidants, became more and more powerful, eventually becoming one of the most powerful individuals in the realm; Emperor Yang also elevated his title to Duke of Xu (許國公). In 607, Yuwen, in order to allow Yun Dingxing (雲定興), the father of Yang Yong's favorite concubine Consort Yun, to join Emperor Yang's regime, persuaded Yun that Yang Yong's sons needed to die, and then persuaded Emperor Yang of the same. Emperor Yang poisoned Yang Yong's oldest son (by Consort Yun), Yang Yan (楊儼) the former Prince of Changning, and exiled Yang Yong's other sons, but eventually had them all killed. It was only after the deaths of Yang Yong's sons that Yuwen was able to recommend Yun to Emperor Yang, who made Yun one of his chief engineers.