If you're trying to translate something specifically about "ki" you might need to explain the context to get a good Spanish translation.
For example:
* "Ki" in a martial arts context might be translated as "energía vital" or "fuerza interna"
* "Ki" in a spiritual context might be translated as "energía universal" or "fuerza cósmica"
Let me know if you have more context and I can help you find a more specific translation!