Ka's Links
While they are twins, Ka is sometimes astounded by how different their ways of thinking are. There is some level of similarity in that both tend to be more calm (especially for Ka considering his firey demeanor), the extent of which is well exceeded by Fu who is by far more carefree and forgiving. Ka still cares for his twin though, but he doubts their relation sometimes...
Fu thinks that Ka is silly, but loves him dearly regardless. He doesn't seem to understand why Ka views them so differently all time, since they have common aspects as well. He thinks that his brother needs to lighten up even more but he doesn't try to change anything about his sibling since he accepts who he is no matter what.