The Parallels are alternative worlds within Rune Springs, existing in the shadow of the regular world. They are imperfect mirrors, showcasing a world where different decisions were made from the real world. They are not real, rather being a hallucination experienced by anyone who enters a Rune Spring. But they do not last forever- each will reset after a short period of time, returning for a brief moment to a perfect reflection of the real world. As this process repeats itself endlessly across history, they are sometimes referred to as the Eternal Dream.
Origins
Like the springs themselves, how Parallels first formed isn't fully understood. It's known that Runes generate within them before being spat out by the respective Rune Spring, but any information beyond that has not been uncovered. The Cult of the Runes believes Parallels are connected to the lingering consciousness of the Liath, but there is no worldwide consensus on their origins.
Generation
After Runes are born into the air from a Rune Spring, they float throughout the world until they are absorbed by a living being. This being, provided they are sufficiently sentient, then generates Personal Runes inside themselves. The Personal Runes then attempt to return to the very Rune Spring the original Runes emerged from. If they are successful, they provide information critical to the generation of a Parallel.
Personal Runes have a shorter lifespan and maximum distance they can travel before fizzling out. As a result, Parallels only extend so far as Personal Runes can return to the spring from. Anything or anyone outside that range will simply not exist within a spring's Parallel.
The Cult of the Runes believes that Runes are pieces of the spirits of the extinct gods, the Liath. This belief goes on to hold that Parallels are a form of communication from the Runes, from their perspective, on how they see the world around them.
Mechanics
Parallels are mirror worlds, mimicking the real world around the Rune Spring. But due to the nature of the Runes, the people inside these mirror worlds make different decisions from their real counterparts. Despite their appearances, Parallels are not truly real. While tangible in some form, the world visible within is a massive illusion, a projection of the Runes. The people in them can be interacted with by interlopers, although projected persons will believe them to be spring spirits.
Parallels only persist for a relatively short time. After an average of three months (the time varying depending on the Rune Spring), the world will reset, becoming for a brief moment exactly like the real world outside the spring. But almost immediately, the people within will begin to make different decisions.
The differences in the decisions they make compared to their real counterparts are influenced by the Runes around them. For example, the Nesilene Rune favors aggressive spells while de-emphasizing defensive ones, and the people within the Nesilene Parallel tend to make more aggressive decisions than their original versions.
Entering a Parallel is accomplished by descending into the correct intercanal in its corresponding Rune Spring. Thousands of mages perform this practice every year, both to meditate in a world made of Runes and to appreciate the fine details of life through the differences visible in the Parallels. The Cult of the Runes requires that each mage make a pilgrimage into the Nesilene Parallel at least once in their lifetime, with many mages making pilgrimages from across Nesilene just to fulfill this requirement.
Parallel Paranoia
Parallel Paranoia is a phenomenon where people fear that something they saw transpire in a Parallel could also occur in the real world. This most commonly forms after a person witnesses something terrible happen to their Parallel self. A person suffering from Parallel Paranoia will usually do anything in their power to prevent what they saw from coming true, even if it involves life-changing or self-destructive action.
There is no known cure. Once a person has exhibited traits of Parallel Paranoia, they are forbidden from entering the Parallel again.
Prism Parallels
Using a Parallel spell and a Prism Lantern, a mage can temporarily create a small, makeshift Parallel around them wherever they want. However, these work substantially differently from regular Parallels. The differences from the real world date back far longer, often being predicated on key historical moments playing out entirely differently.