Unknown Shadows

From Glen Cook Wiki

Supernatural creatures which inhabit Hsien, aka the Land of Unknown Shadows. They were created by the original Shadowmasters who enslaved Hsien in a past age, using the Shadows from the Glittering Plain as base material. While regular Shadows are basically mindless, shapeless, tormented entities which know nothing but a ravenous hunger for human life force, the Unknown Shadows are (at least somewhat) intelligent and take the form of various distinct creatures and species. Some of the largest, such as the carnivorous duck or the wowsey, appear to be one of a kind. Others, such as the baobhas, seem to be fairly numerous. Like Shadows, they are often difficult to see, no more than a two-dimensional silhouette at the corner of your eye which disappears under direct scrutiny. However, they can assume shape and even color when they want, and mimic humans or animals (e.g. crows) with real physical presence.

The Unknown Shadows absolutely worship Tobo and will do anything for him, even following him across the Glittering Plain. To others, they can be somewhat more dangerous.