called p'o, and written with the characters for 'white' and 'demon,' that is, 'white ghost,' belongs to the lower, earthbound, bodily soul, the yin principle, and is therefore feminine. After death, it sinks downward and becomes kuei (demon), often explained as 'the one who returns' (i.e., to earth), a revenant, a ghost.
Jung identifies the revenant explicitly with the Chinese p'o soul — the earthbound, yin, feminine soul-component that, unlike the ascending animus, returns to matter as demon or ghost after death.
, Collected Works Volume 3: The Psychogenesis of Mental Disease, 1907thesis