Moon phantom?

Hero’s existence is ephemeral, based on the phase of the moon. (Why - What caused this?) A crime solving detective, he/she is only fully “solid”, in this world, when the moon is full. When there is no moon, he/she can only indirectly interact with the world through supreme concentration and only in such manners as slight movements of objects, a barely perceived whisper or a tickle on the back of a person’s neck. As moon begins to appear the hero begins to “solidify” into our world and based on % of phase has several different powers. I.E if there is a crescent moon, hero can walk through walls, float on a wind current (devise some costume device for ability to control direction). When moon is half-full gains ability to blend into shadows to be unseen – now too solid to pass through solid objects, body remains incredibly light and partially transparent , giving ability to easily climb walls, leap up to 20 ft etc. (has full strength for these activities but body mass too light to effectively engage in physical combat) At Full moon, hero is completely solid and visible. During this period he/she is at most vulnerable state but has very good martial art skills (aikido).