Byleth - Il Demone Dell'Incesto (1972)

Mark Damon stars in this decidedly average Italian period horror movie as an unstable duke with incestuous feelings towards sister Claudia Gravy.
 Director Leopoldo Savona doesn't hold back on the flesh content with softcore fumblings abound, it's just a pity he didn't concentrate more on the suspense elements as it may well have made the movie
a lot more entertaining.
  To be honest i've never been a fan of Damon and this does nothing to change my opinion, a film i think that will be quickly forgotten.