Name Workshop
Idea seeds:
Abyssal ocean
Void
Vaccum
Vaccyssal Mist??
Cosmic abyss
Primordial mists
Edge of the world
Brainstorm Concept
Basically, every shard/quilt needs an edge. At the edge there is some form of boundary or terminus. The terminus can be discrete or fuzzy and can take whatever form it needs to take to make sense for that shard/quilt.
Example might be a high seas shard would have the edge of the world waterfall that ships would fall off, a Cloud City might have an impossible fall into the clouds below, a Apollo moon landing colony might have outer space, there might be a colossal wall that defines the edge with nothing on the other side, the mists of the forest might become impossibly thick.
Anything that goes too far beyond the edge is likely to dissociate into primordial energy and fave to oblivion. Specific shards, quilts, or plots might allow passage through the void but those would be major endgame type story arcs, not a matter of course.
The void is related to the vanishing viaduct, which is essentially tendrils of the void or rather when shards form a quilt, there are thin seams where the void remains. Getting lost in the viaduct will lead you into the void. The void is essentially a barrier of indefinite distance between meta regions.