Wolf Frankenstein is the villain of this piece
Not Ygor, not the Monster, but Wolf more than anyone else. First, on arriving in Frankenstein, he promises the suspicious townspeople they have nothing to fear from him. Then he treats the tales of what his father's creation caused with great disdain and jumps at the chance to continue his father's work, even after hearing the commissioner's first-hand experience of the Monster. Then he goes and does it all again, directly causing the death of at least four people, and only being alarmed when his own family is threatened. And after pushing the Monster down into the sulphur pit, he leaves the town with smiles all around. He should have been put on trial for murder. Anyone agree?
If there is a hero in the piece, it's police commissioner Krogh, who again confronts the Monster despite the trauma he suffered as a child, having his arm ripped off by it.