The Dark Guardian

Ever since I play BBS and saw the Dark Guardian in the final episode I've wondered if the Dark Guardian is the same one that Ansem Seeker of Darkness uses because we know the one the Terra-nort uses is a prison for Terra's heart but Ansem SoD is a Heartless and Heartless are beings who's heart has been consumed by darkness meaning both Xehanort and Terra's heart were completely consumed by darkness so there would be no need for a cage