In spring 385, upon hearing news that Murong Wei had been killed, Murong Chong declared himself emperor (with his state later known as Western Yan). Murong Sheng was, however, not impressed with Murong Chong, and he secretly told Murong Rou that he believed that Murong Chong will amount to nothing. His judgment was correct, for although Murong Chong captured Chang'an in summer 385, he did not govern his people well, and his Xianbei people became resentful that he stayed in Chang'an (both because he liked the city and because he feared Murong Chui) rather than seeking to head back east to their homeland. In spring 386, the general Han Yan () assassinated Murong Chong. Western Yan forces than abandoned Chang'an and headed east, toward home—a journey during which they went through a succession of five more leaders (Duan Sui, Murong Yi, Murong Yao, Murong Zhong, and Murong Yong) within a span of a few months, with the regime stabilizing under Murong Yong, who settled down at the capital of Zhangzi (長子, in modern Changzhi, Shanxi). Murong Sheng, along with his uncle Murong Rou and brother Murong Hui, settled in as well.