The reason why Hideki killed Dylin was because Dylin had rebelled within the family and killed the chief of the family, Sanxing, as well as other important members. Dylin rebelled because the Zi Chuan family did not trust him, and as the commander, he had to quell the rebellion. As the heir of the Zichuan family, Zichuan Ning escaped to the Far East and asked for help from Zichuan Xiu to defeat Dylin and take back the capital. In the end, Hideki attacked Dylin. After an intense battle, Dylin was defeated. Hideki supported Hideki and returned to the Imperial Capital. As for the specific motive and background, the search results did not mention it.