When openly displaying her true nature, the infernal creature's natural form is one of exaggerated sexuality - with large, soft, breasts and ample curves clearly intended to draw the eye. Her skin is a shade of dark red - smooth, and entirely free of any blemish. Her legs will typically end in a pair of cloven hooves, and a pair of curved horns will often extend from her forehead. She will also often possess a strong, and agile, tail - and, may even possess a pair of large, bat-like, wings.
In her true form, there also seems to be a roughly equal chance that she will present herself as a true female, or that she might come equipped with something extra.
While the succubus may assume a wide variety of other forms, when she wishes to disguise herself, there does seem to be on in particular that she prefers. This stolen form is similarly beautiful - though, perhaps, not to the same exaggerated extent. in this form, she will appear as a lovely young woman with blonde hair and pale skin. She will be tall, though not quite as tall as in her natural form, and with a figure that seems toned from frequent exercise.
While disguised in this way, she will most often restrict herself to a purely female form - though, she may make the occasional exception.