Clavicus Vile is the Daedric Prince whose sphere is the granting of power and wishes through ritual invocations and pacts. Vile has a companion named Barbas. While capable of selective shapeshifting, the form it assumes most of the time is that of a dog. Vile himself is depicted as a small jovial fellow with horns protruding from his forehead. He is aptly described as a Daedra who likes souls for the sake of having them.
For more information, see the main lore article.