Martial cultivation and moral virtue
Wuxia's central principle is that martial skill and moral character are not separate — that true mastery of a fighting art requires inner cultivation as well as physical training, and that a character who is technically brilliant but morally corrupt has not truly mastered their art. Writing wuxia means building a world where this connection is real: where the highest martial achievements are available only to those who have also achieved genuine ethical cultivation, and where moral corruption produces specific deficiencies in martial performance. This is not allegorical — it is the genre's cosmology, and it should be built into the story's causal logic.