Niffty is a sinner demon who works as both the maid and cook for the Hazbin Hotel. She was summoned to work in the Hotel along with Husk by their mutual associate, Alastor.

Niffty is hyper, spontaneous, and agile, being very quick on her feet. She is easily entertained, easily distracted, and easily excitable. She dislikes when there is a mess in any room, and has a fixation on men in general. However, she appears to only like "bad boys". She isn't afraid to get dirty, and enjoys cleaning everyone's messes all with a gleeful, yet creepy charm. Despite all of her twistiness, she does have some kind of standards for how she views who is "bad". She has masochistic tendencies, as well as sadistic. She is also shown to suffer from camera shyness, as whenever a camera begins filming her she goes into a state of hypnotic trance where she doesn't move, blink or speak, just stares at the camera until recording is done. Niffty has an extreme case of obsessive compulsive disorder, constantly cleaning the Hotel and obsession with ridding any bugs she sees to the point she would bring out a knife just to kill them. Even when being taken outside of the Hotel, she would be constantly cleaning any mess. She is a kleptomaniac since she collects things like hair or fur from men she is obsessed with.