Excerpt from "A Dissertation on the Realms," by H.R.M. Thansor.
Chapter 14, introduction. "The eighth realm of Peris is the first of the realms that traditional portals simply cannot be opened into. No Realm Mage has ever been documented as setting foot in this land, though it is quite certain that not many would want to. I, myself, have no desire to ever enter the Eighth Realm, even if a way were suddenly discovered.
Peris, as with many other realms, is time-locked. Every single day, at exactly noon, a portal may be opened for a period of about half an hour. However, this portal allows only for passive viewing, as if peering through a window pane. Attempting to cross through this window will result in the portal breaking, forcing you to re-cast the portal once more. Unlike many of the other time-locked realms, Peris does seem to be in sync with Calsin, in that portals may be cast from anywhere in Calsin and see into a corresponding location in Peris (rather than all portals opening to the same location). As such, detailed maps may be found of the land, as mages wandered far and wide gathering the information.
However, as I said, I doubt very strongly that many would care to enter Peris. It is likely that, upon peering through a portal for the first time, you will notice nothing but undead. In fact, even with experience, it is possible to become sidetracked by the sheer number of the monsters. Estimates at the number of zombies in that world have been estimated in the billions, if not higher. The ground that they walk on appears as rotten as they are, with only twisted grass stems and charred trees rising from the flat, marshy ground. No signs of civilization have ever been found, indicating that the realm was either born undead, or the last remnants died out so long ago that there simply isn't any traces of them left."