Hell hounds1 are beasts of massive power, used by other daedra to track and hunt their prospective victims. Hounds are nonsentient and cannot be controlled without the aid of another daedra. When they find themselves on the Material Plane, they usually fall back on predatory instincts, hunting and killing whatever they can catch. Most of these are found and eliminated by the Lothanasi in relatively short order.
Suspira has a hell hound named Jambris that often accompanies her on her ventures into the mortal world. When in disguise, Jambris appears to be a large mastiff.