I love any woman whatever. He lives anywhere at all. This beginning says that you either don't know or that there is no answer. For selecting an individual out of a group. KIU can mean either who or which .
Similar remarks apply to the other -U correlatives.
For naming a thing. As the -O indicates, the answer should always be a noun. For describing something. The -A will help you recognize the need to answer with an adjective. For pointing out a location.