The victim of a curse, he became a lycanthrope and was locked away in his cellar laboratory.
You do not even have to have been bitten by a lycanthrope in a misty forest where you have stupidly wandered.
Another way in which a demon is held to cause disease is by introducing itself into the patient's body and sucking his blood; the Malays believe that a woman who dies in childbirth becomes a langsuir and sucks the blood of children; victims of the lycanthrope are sometimes said to be done to death in the same way; and it is commonly believed in Africa that the wizard has the power of killing people in this way, probably with the aid of a familiar.