Arcane Plane

The physical world of Rideen is only one part of a vast network of other planes of existence. Some are like Rideen, but barren and inhospitable. Others are populated with life not entirely unlike the animals of this world. Still others are something else entirely, not just alternate worlds but alternate states of existence, where the laws of physics are entirely different. The arcane plane is one such state.

The arcane plane, sometimes abbreviated "the arc," is a nearly infinite swirling maelstrom of chaos and energy, where the laws of physics are a suggestion and objectivity is a joke. A boiling sea of entropy so incompatible with sentient life than any creature who entered it would immediately cease to exist. Yet despite this, nearly all life in Rideen is dependent on it for survival, and it is the source of nearly all magic in the world.

Arcane Bridges
Almost every living being in the material world carries in their mind a "bridge" of sorts, between themselves and the arc. When living beings hold an idea in their mind, that idea crosses the bridge, and imposes itself on the arcane sea, forming structure out of the chaos. Simply put, the arc is a plane of thought, where the imaginations of sentient creatures manifest physical form.

Arcane Bridges and Gods
The images formed in the arc are temporary structures - they flit into existence when a mind considers them, and disappear when the mind discards them. But if enough living creatures all hold onto an idea strongly enough, (whether they intend to or not) sometimes that idea can take on a quite literal life of their own. In time, a manifestation of that idea can gain its own identity, its own will. Gods and other arcane beings are the sentient products of the minds of entire cultures.

Arcane Bridges and Magic
The mental bridge to the arc goes both ways: images, structures, and even raw energy in the arcane plane can pass through the bridge and into the mind and body of a living being. Those with particularly strong connections to the arc can often channel its power through their bodies, "nudging" the laws of physics around them and altering the material world. This is the nature of magic.

Origin of Arcane Bridges
It's unknown exactly where in Rideen's evolutionary tree the bridge appeared, or what its purpose originally was. Some scholars believe its purpose is to introduce small amounts of disorder into the minds of living creatures, and is therefore the origin of creativity, free will, perhaps even the soul. Others believe that the bridge evolved as a source of energy, allowing creatures to metabolize the pure energy of the arc in times of scarcity. Still others believe that the bridge was a gift from the arcane gods, or perhaps some even more powerful entity.

Whatever its original purpose, the arcane bridge is tied inextricably to the structure of the brain. If a creature's bridge to the arc is destroyed through any means, the creature dies, practically instantaneously (this is in part why many believe it to be the source or location of the soul).

Beings Without Arcane Connections
While nearly all complex life in Rideen has a connection to the arc, there are a few noticeable exceptions. Microorganisms and some invertebrates lack the bridge. In addition, beasts from the vyrcane plane who became endemic to Rideen after the Sundering possess bridges to the epcane plane instead.

The koromein are the only sapient species in Rideen who do not possess a magical bridge of any kind. Instead, a hard shell of magic-blocking korocite makes them highly resistant to nearly all magic, both arcane and epcane, both benevolent and harmful. It's unknown exactly how the koromein are able to live without a bridge, or how they came to exist without one. Some speculate that the koromein evolved entirely separately from the rest of life on Rideen, though how this could be true is unclear. Others believe that the koromein were deliberately created without a bridge by some higher, unknown power. Still others hold that the koromein people have no soul or internal consciousness, and the bridge can only exist in organisms with sentience. Whatever the case may be, it has been a subject of great debate in Rideen, and the cause of no small amount of prejudice against the koromein people.

The Epcane Plane
The epcane plane is a similar realm to the arcane plane, with an opposite polarity. Magic from the epcane and arcane plane cancel each other out on contact, an effect that can be deadly to any being dependent on an arcane bridge for survival.