On Elder Soteria the veil between worlds is wearing thin.
The evil things of the world were trapped in the Dark Aether, a world between worlds that was created in the final acts of the Timeless Ones before they vanished.
A mirror has special power, the obvious ability to reflect sight from one place to another and allow one to see themselves is simply the surface. Mirrors have the special ability to build a bridge between planes of existence, though they must be prepared to do so.
The mirror must be made from pure and polished silver, once made it must then be infused with magical or psionic energy until the metal takes on a bluish-white hue, casting its reflections of the material plane a soft hint of blue color.
Once infused with energy, the mirror will begin to, itself, bridge planes together haphazardly, to control this one must place the mirror within a frame which contains Aanneomi runes, the runes will form framework in magic to control the mirror’s bridging.
When set into a properly constructed frame, the mirror can then safely controlled and the runes will keep the energy from diffusing from the metal while at the same time providing a way to focus and direct the bridge.
The only natural surface which can create a similar bridge is that of pure water. The water must be calm and undisturbed and resting in a receptacle with not only runes to control the effect but to augment the natural reflective properties of the water. Since water itself is an item of potent magical and psionic power, it does not need to be infused but instead kept protected from contamination, disruption and given focus.
A shadow of the real world, created in parallel to the normal prime material plane but separated from it. This plane can be accessed through using the power of mirrors to bridge planes of existence. Still powerful wards were created by the Ageless Ones so that transit between planes would be impossible. Those wards pushed the Dark Aether away from the material plane even though the nature of both planes being so close together would naturally attract them.
The wards are created using rune stones with carefully constructed Aanneomi runes on both sides of the divide. The barrier between the Dark Aether and Elder Soteria was created by the Ageless Ones. This barrier is wearing thin but it isn’t just wearing thin between the Dark Aether and Elder Soteria, that barrier is somehow having a diminishing effect on the other inter-planar barriers separating the living and the dead, dreams and reality, and a host of other planes which should never touch directly.
On the side of the material plane, the stones are placed centered within powerful wells and most are buried there, locked away underground away from prying eyes and sticky fingers. The stones themselves are massive, being at least twice as tall as a person and as wide as 4 or 5 people. They are made of amethyst with runes carved deep in the surface and the inlaid with pure silver. The sheer amount of magical energy present in the stones increases their weight and hardness to beyond the point of even several times that of diamond.
The stones themselves have been seen by many and much of the runes are recorded in very old records at the Rose Palace, though no one has ever known exactly how the runes work. The stones was woven into the very fabric of magic of Elder Soteria, they have been there is long and the barrier they produce has been there so long that there is now a give and take with the flows of magic of the ley lines, wells, and the stones. The basic idea of the stones is to provide a barrier of purification and protection which is focused particularly on keeping the Dark Aether divided from the material plane.
On the opposing side are made of the material Black Obsidian, though this is hardly spoken of in any but the oldest of the old records residing at the Rose Palace. The exact runes and reasons placed on these stones are completely unrecorded anywhere, the Ageless Ones warned that such magic could be turned to very dark purposes and did not wish anyone to be able to learn its foundations.
These stones serve a much darker purpose than the ones on Elder Soteria, where as Elder Soteria contains magic which protects it, these stones contain magic which strives to stop the plane from being anchored to the material plane. Without such an anchor this plane drifts slightly in time and space relative to the material plane of Elder Soteria.