Naberius
Cerbere/ Cerberus/ Naberius is a strong and powerful demon commanding 29 legions who appears as a three headed dog or a raven.
Below you will find a list of demons that can take the form of a dog.
Glasya-Labolas
Caacrinolaas/Glasya-Labolas, the 25th spirit, is a President and Earl who appears in the form of a dog with gryphon wings.