The only natives of Limbo, the Void Watchers are more commonly referred to as just Watchers.
The watchers appear as simply large masses of darkness with a single large red eye, the same seen in the 'skies' of their home dimension. The eye only opens when a being from reality nears them.
As being from the void, they are not life forms, they possess no 'real' bodies as they are not composed of matter as we know it. While they normally appear only in the void they also appear on worlds/dimensions that are dying/collapsing, although they can only be perceived by special beings.
Their true powers are unknown but it is known that the Weekee are afraid of them, especially the Rebels.