What are peoples feelings about D&D using the term "ki", in the context of cultural appropriation?
Generally, I find it to be a useful near-universal term, whose meaning is relatively clear, and that applies to any Martial class including any superhuman feats. But if D&D employs it, it would also reuse it in contexts that might misrepresent Japanese meaning? (And similarly other cognates such as Chinese qi.)
If it is necessary to avoid this potential problematic if misrepresentation, maybe use a term like "aura" or "lifeforce". The Greek term would actually be psukhe (psyche), but modern psychology appropriated it to emphasize the unconscious aspects of the mind. But now psyche seems almost synonymous with mind in English. I like "aura" best, as its mystical capacities are clearer since it is more than muscle.