We first meet the Wizard Cornelia in episode 22 being confronted by The Flock in her camp. She wears a salmon coloured waistcoat with a high collar typical of a member of The Natural Order .
She has a nervous disposition and is quite concerned with neatness and cleanliness - hence her name.
In episode 25 , Cornelia fell foul to a magical booby trap when attempting to open a small chest the party had discovered previously - this caused her to shrink in size. This curse was lifted by Chalmers the priest in Winkburgh , although it wasn't reversed - she was left approximately 1½' (45cm) tall.