Hidden World

The Hidden World is a phase of the world, where magic gods other than Othinus resided. It was later breached by Aleister Crowley in order to challenge the magic gods.

Etymology
Kakuriyo (隠世) is a Shinto term that refers to the world of the gods and spirits, and is also interpreted as the world after. In contrast utsushiyo means visible or open world, the world of humans.

Principles
In this phase, the concepts of distance and time don't matter, and direction and depth are also indistinguishable. When Niang-Niang appeared before Nephthys and the High Priest, she tells that she was a "hair's breadth and an infinite distance away", implying that the phase is not a fixed space and that time doesn't pass in the phase. Indeed, the magic gods rely on "destiny's hand" to allow them to meet each other.

The phase is described as "dark" or a "black world", but it is referenced that it may not be wholly accurate to describe it as both being dark or being a place. All in all it is similar to the Black World, and the difference between them being that the Hidden World is a phase where the Magic Gods of the true Gremlin reside and that even Othinus could not detect its presence, let alone destroy it.

A special property of this phase is that it prevents the magic gods from escaping, though it is implied that they are there willingly in order to not influence the world because their sheer existence could destroy it, though they still do complain about being there after the events of Othinus' remaking of the world and its aftermath.

After Aleister Crowley breached the phase and entered it, the Hidden World was apparently "destroyed" or "lost", which implies that this phase had lost its purpose in separating the magic gods from the rest of the existing world. High Priest, Nephthys, and Niang-Niang were the first known magic gods to have entered the existing world after losing their Hidden World, consequently having to weaken themselves to prevent them from destroying the world for merely existing.