The Raving In-betweens
'I didn't miss the end of the world [Final Part]'
The Crushing Fist (Part 2), Our Final Acts (Multiple parts)
The Raving In-betweens are not a form of reality in their own right, rather they are the section of multi-dimensional space that exists between realities which have not been bridged through the use of Portals.
Typically, the Raving In-betweens would not be accessible, however due to the compression of The Crushing Fist, cracks and fissures have formed in many realities within the Outer Shield. Such fissures are characterized by a jagged purple glowing crack, which can be entered by people to travel between realities.
Each person who enters the Raving In-betweens experiences them differently. Typically, travelers would report strange sounds and smells, as well as blasting winds. While some would see the path beneath them as grey flat stone, others would experience it as a grassy lawn, or in the case of Conn Thompson, white hospital tiles. All duplicates of Noah Fulmer reported travelling to be like wading through glimmering dust that pulled at them like tar. A consistent aspect of the experience was that anyone who looked up would turn completely insane.
The perceived physical distance traveled apparently correlates with the distance between realities within the multiverse. As The Crushing Fist has continued to compress the Outer Shield, this distance has decreased significantly.