You could call it a Construct or one of the Returned. Maybe a Draugr. It's not entirely the same concept, but Draugr can adjust their bodies to be much larger than their fleshy selves. There is also the Leich or Lich, but I think DnD has overplayed that name so its original ambiguity is kind of lost. How about a Ghast?
You could also call him an animus, if you don't mind all of the psychology students snickering every time. Animus refers to the latin term for a soul, but its your world. Do as you will.
Then there are the words that deal with what they do rather than are, like calling them Ravagers or Reavers.
Let's see, since you mentioned Frankenstein's monster, he was described as an ogre, wretch, creation and fiend. Not very descriptive or unique, though. You could call him a Promethean, after the name of that book.
All I got for now.