Perhaps the most sophisticated aspect of "The Dunwich Horror" is its handling of characters. On its surface, it seems puzzlingly without a protagonist. Its focus shifts from Lavinia Whateley to her father "Old" Whateley to her son Wilbur Whateley and then to Dr. Armitage, yet the narrative holds together and suspense is maintained.

This is because the real main character is the usually off-stage and invisible "horror" itself. Soon after the birth of Wilbur, Old Whateley declares that "some day yew falks'll hear a child o' Lavinny's a-callin' its father's name on the top o' Sentinel Hill!" This would seem to be Wilbur, although the mysterious happenings at the Whateley's farm suggest that Old Whateley may have had someone else in mind. The Whateleys buy cattle in extraordinary quantities. Most of these disappear, while others are seen to be anemic and to have strange wounds about their bodies...