In all of Centasi history, from the mythical prehistory of the Old Kingdom to the countless wars and petty conflicts of the modern age of the Hundred, there is no figure so feared, so influential, so historical, as the Howler.
The Sark-Hound is a basic form of Sark which is created for a very specific purpose, to wit, the hunting and killing of the necromancer’s enemies (in Centas, the place of the banal zombie is taken by these creatures).
If you want to add a "supernatural" touch to your campaign, define the rules of magic and the universe. Make your players comfortable with those rules. Then your new supernatural creatures must then break those rules.