The World of Emptiness is the home dimension of demons and monsters, some of which manage to cross into our dimension, wreaking havoc. The beings summoned by the Pale Gate Rune also hail from the World of Emptiness. The Gate Rune, one of the 27 True Runes, holds the ability to open portals to this dimension and other strange beings, such as Yohn, also reside within this place.
The World of Emptiness has been described as being dark and gloomy. This dimension is also said to be where the dead are sent temporarily, although it does not appear that this state is permanent. Given the wide variety of beings inhabiting the World of Emptiness, it is clear that the name refers to the dimension's bleak landscape, rather than a lack of inhabitants.