The Obscura Veil is the connective tissue between story universes — the membrane that separates them while also, in rare and poorly understood ways, allowing something to pass between them. It is not a place. It cannot be visited, mapped, or measured. It is the condition of there being more than one world.
Most inhabitants of child universes have no awareness of it. Those who develop awareness of it — typically through anomalous events, inherited memory, or exposure to things that should not exist in their world — rarely survive long enough to share that awareness in any useful form.
The Veil does not have a will. It does not act. It simply is — the way gravity simply is. The entity that has learned to move through it, however, is another matter entirely.