Nibbil is assigned to be the guardian of Annie’s conscience, by the Queen of Annie’s conscience after Annie fantasizes about her neighbor, Yuriko. Nibbil is supposed to be Annie’s “harsh new taskmaster,” but ends up being “dirtier” than Annie. The two hit it off immediately and become friends and lovers. In the second issue she is revealed to be able to change her size at will, all though she is only ever shown as her regular size (a few inches tall) or Annie’s size.
While Nibbil is a part of Annie’s conscience, she is also a physical manifestation, meaning that she can interact with people and objects in Annie’s world as if she were a normal human. Because of this she is able to join Annie in any activity, such as going for a drive, shopping, eating at a restaurant, etc. In the final issue Sage asks Annie about the relationship between Annie and Nibbil, and wonders why she doesn’t have her own physical manifestation off a conscience. Nibbil jokingly replies that perhaps Sage just doesn’t have a conscience at all.
Personality
Nibbil’s personality is mostly sexual. In the few scenes in which she is not thinking about sex, she is shown to have a very playful personality and active imagination. She enjoys dressing up, roleplay, and cosplay, and is shown to enjoy a handheld racing game and large stuffed bunnies in the final issue, and apparently does not like spiders.