杨玄感
While Yang Su was alive, Emperor Yang had been deeply apprehensive of Yang Su's power and angry with Yang Su's arrogance, and after Yang Su's death, he made the comment, "If Yang Su did not die, his clan would have eventually been exterminated." Yang Xuangan heard rumors of this comment, and was apprehensive of Emperor Yang. As he saw how the imperial governance had deteriorated under Emperor Yang and believed how many officials who were prior subordinates of his father Yang Su would support him, he plotted to depose Emperor Yang and declaring Emperor Yang's nephew Yang Hao the Prince of Qin emperor. As he followed Emperor Yang on a campaign against Tuyuhun in 609, he saw how disorganized the Emperor's train was and considered an ambush at that point, but his uncle Yang Shen (楊慎) dissuaded him from the action. Later, during Emperor Yang's preparation for war against Goguryeo, Yang Xuangan volunteered to serve, and his volunteering greatly pleased Emperor Yang, who trusted him more and more and gave him input in important governmental matters.