Professor Dementor is a supervillain and mad scientist, who seeks to dominate the world. He is a sort of foil to Dr. Drakken, as they are similar in villainy style, but Dementor seems to be more famous and successful. His real surname is Demenz (the German word for dementia), his first name is unknown. (from Kim Possible wiki: http://kimpossible.wikia.com/wiki/Professor_Dementor)