The Abyss
The Abyss, also known as The Void, is a theoretical plane beyond Unreality, wherein things even less “real” than the Unreal exist as possibilities.
Very little evidence exists of contact from The Abyss. Some contact with Aboleths suggests all Aboleths are extensions of one being which does not exist, or “exists outside of existence.”
The Abyss is thought not to experience time. In theory, an entity or object that is utterly obliterated beyond the capacity for revival by conventional means could be retrieved if it could be coaxed into a layer of Unreality through the use of powerful ritual. If retrieved in this way, the entity or object should appear exactly as it would have been the moment after obliteration, should the obliteration not have occurred.