Hailing from the Elemental Plane of Air, fog hounds are slender, canine creatures made of semi-solid cloudstuff, becoming less substantial when exposed to fog and mist. Though smarter than an average animal, fog hounds are still beasts, having neither language nor culture.

Despite their extraplanar origin, fog hounds are found on the Material Plane with surprising frequency. On that plane, they are most often found in large fog banks rolling in off bodies of water, and in large patches of ground fog found in low-lying river valleys. Sages speculate that such large areas of fog generate a tenuous connection with the Plane of Air, one that fog hounds can permeate when in gaseous form.

The same rumors that hint at the existence of magical cloud islands inhabited by cloud giants also suggest that fog hounds can be found in such legendary locales. This could suggest that such cloud islands exist in areas where heavy fog is common, or that such islands are actually features of the Elemental Plane of Air. Until such an island is found to exist, either claim is mere speculation.

A 5th-level neutral spellcaster with the Improved Familiar feat can gain a fog hound as a familiar.