I have a book called (with relentless logic) "A Book of Old Ballads" selected and introduced by Beverley Nichols, Hutchinson, London 1934. It contains 16 wonderful illustrations by H.M.Brock and one of these is for the 3 Ravens. It shows a flesh and blood human female kneeling by the fallen knight. One definition of leman that I've found is a "sweetheart". Mystery? What mystery?