The Flickering Realms is a fictional dimension in the Marvel universe which first appeared in 1995 in Wolverine Annual Vol 2 1995 as the N'Garai dimension and it appeared as Chthon's dimension in the next year, in issue #90 of the 1st volume of Doctor Strange: Sorcerer Supreme.
The Flickering Realms (aka, the Dimension of the Darkhold) was created by Chthon, one of the Old Ones. The dimension has no map, due to its constantly changing landscape. One may cross stones, then swamps, followed by snow, and then sands; in which the snow burns like fire and the stones bleed. The only thing that is constant in the dimension is danger. Within the dimension is the dimension of the N'Garai which is full of demons.