Yunru's younger brother.Siyuan is a middle school boy who is in the rebellious stage. Regarding the situation at home and the contribution of his sister and mother to him, Siyuan does not ignore it. However, because he is still young and unable to change the current situation, Siyuan always feels unspeakable anger.He was angry that his existence had caused his mother to suffer a lot and his sister to suffer a lot of injustice.