I finished reading Frankenstein last night. I am amazed that Mary Shelley was only 19 when she wrote it in 1816. Looking at her book with fresh 'author' eyes, I see a tragic tale defined not so much by circumstance but by characters.
Victor, Henry, Elizabeth, and even Victor's creation are all at first conveyed as innocents. Their purity sets the stage for the diabolical acts that follow. I could go endlessly on, but I've secured my lesson learned. Not all stories mandate an evil villain.
It reminds me of the preacher who tells a joke on Sunday morning. He always garners a response. Often times, the lively response elicited isn't from the content so much as the humor wasn't anticipated in a church service.
Sometimes the scariest of stories need that same offsetting base. The horrible seems worse because we first tasted the goodness, a clearing of the pallet. Mary Shelley gives that in Frankenstein with her goodly characters and to a lesser extent, serene settings.