Most likely there is the monster itself as a main character. It might be a grotesque being that is trying to find its place in the world after being created. There could also be a sidekick or an assistant to the scientist who might have second thoughts about the whole experiment.
There could be a female character in the story, perhaps a love interest for the scientist or someone who is trying to stop the monster. Maybe she represents the moral compass in the story and is horrified by what the scientist has done. However, without more details about the 'the frankenscience monster story', this is all speculation.