Epcane Plane

The epcane plane, sometimes abbreviated "the ep," is a sort of mirror to the arcane plane. It sits adjacent to the physical world just as the arcane plane does, and has almost the exact same physical properties. Like the arc, the ep is a maelstrom of chaos and entropy where the conventional laws of physics do not apply. The only major difference is that the two planes are polar opposites, and energy from each will cancel out energy from the other.

For a long time the ep lay undiscovered by those in Rideen. This is because even though it is nearly identical to the arcane plane, almost no living being native to Rideen has a connection to it. Whether by evolutionary fluke or some other means, nearly all life in Rideen evolved an arcane rather than epcane bridge. The epcane plane was finally discovered in the aftermath of The Sundering, an event in which beings from another world, connected to the epcane plane instead of the arcane plane, invaded Rideen, nearly destroying civilization. It is believed that the Sundering shifted the arrangement of the planes of reality, making it possibly for epcane magic to enter the physical world for the very first time.

Dangers of Epcane Energy
Although it is practically identical to arcane energy sources, the magical energy produced by epcane sources is oppositely "polarized," and when arcane and epcane magic come into contact, they cancel each other out completely. This makes epcane energy highly toxic to nearly all life in Rideen, as it can damage the arcane bridge that they rely on for survival. In addition, because it is a relatively new addition to the world, life on Rideen has not evolved natural defenses to it, as they have to arcane magic. These facts combine to make epcane magic extremely deadly. A small amount, highly concentrated, can instantly destroy the arcane bridge, killing a creature instantly. Though warding magical devices exist to provide artificial protection from this danger, even those wearing wards know that epcane magic is nothing to be trifled with.

Shadowborn
The Sundering had consequences beyond introducing epcane magic into the world. In the years following, people began to notice children born with an "inverted bridge," one that connected to the epcane plane instead of the arcane plane. These individuals can directly channel deadly epcane magic without being vulnerable to it themselves, making them extremely dangerous sorcerers. With the ability to completely bypass a person's natural magical defenses, they can kill with a single thought, control the minds and nervous systems of others, and wreck havoc upon others. Such individuals are called "shadowborn."

One side effect of a shadownborn's epcane bridge is that many conventional magical powers malfunction on shadowborn individuals. Magical healing can cause severe burns. Exposure to powerful enchanted items can lead to fatigue, even damage to the nervous system in the long term.

Most shadowborn who survive the superstition and hatred of their kind lead ordinary lives. Some may never even learn about their capabilities. However, Rideen's history has been marked by the dark legacy of shadowborn who use their powers for evil. The most notable of these was the Greskel Necrolords, a dynasty of sorcerer-kings who deposed the Khrisholm family and ruled Grellain from 615 to 643 PSE. Though their bloodthirsty regime has long since been overthrown, the memory of a life spent under shadowborn control makes the ruby ikryn particularly intolerant of shadowborn.

The Winter Event
An explosion of epcane magic that rendered the country of Grellain uninhabitable for about a century. The main article on this event can be found here

Vyrcane Creatures
While every being native to Rideen evolved with an arcane bridge, there are other worlds beyond this one. During the Sundering, creatures from the vyrcane plane poured into this world. The vyrcane plane is much like the physical world of Rideen in material properties, but with a vastly different natural environment has evolved an entirely different ecology. Wildlife from the vyrcane planes has evolved a connection to the ep, rather than the arc. This makes vyrcane creatures that have evolved magical abilities extremely dangerous, for the same reason that epcane energy itself is dangerous. Vyrcane beasts have been reported to kill, paralyze, or even control minds without even touching their prey.

Fortunately, because vyrcane creatures evolved without the presence of the arc, they are just as vulnerable to arcane magic as Rideen's native life is to epcane magic.

In Rideen's Culture
For obvious reasons - not the least of which was a nearly world-ending catastrophe, a magical explosion that poisoned an entire country, and a legacy of dark magic - epcane magic is thought of as evil, and is sometimes referred to as necromancy.