Final answer:
Without additional context, it is not possible to determine what Ky intends to teach Cassia. The texts suggest themes of learning and personal growth.
Step-by-step explanation:
The provided text excerpts appear to be from a work of fiction, and as such, the context needed to accurately complete the sentence "Ky said he will someday teach Cassia to _________" is not given. Without more context or details, it is not possible to specifically determine what Ky intends to teach Cassia.
However, the texts do suggest themes of learning and personal growth, indicating the possibility that Ky wants to impart some valuable knowledge or skill to Cassia that may aid in her own personal journey or contribute to her sense of security and autonomy, much like the characters shown are learning to manage and find peace in their respective situations.