"With the construction of the Golden Cage came a fundamental shift in the way the world worked - the politics between Realms, and the the potential for future conflicts. No longer was it possible for an Aurali unit to simply fly from Astrum into hostile territory... and this was equally true in reverse as well. This imposed upon the world a kind of enforced peace which has stood until this day. Of course, scholars, philosophers and historians may continue to debate whether the constancy of living in a cage, large though it may be, was a fair price.
— from the preface to volume one of "The Cage of War: Recounting the Events and Influence of the Caelestise-Sura War" by Eiryen Nesaleen


Overview

Many millennia ago, when the Caelestise-Sura War had been raging for over 250 years, a certain group of powerful Mortal, Demon and Celestial magic-users and psions came together and plotted its immediate end. The undertaking that followed was neither swift nor simple, and sacrifices were made in its doing... but they were undeniably successful: when the Creators of the Cage made the golden walls rise, the war was dragged, unwillingly, to its end.

Opinions may differ on whether the result was worth the cost, but the wall has unimaginably held strong for all the tens of thousands of years that followed - long past the death of its architect, Peydin Kalil, and likely past some of its immortal weavers, as well. Though that is difficult to tell, as not a one of them has ever claimed responsibility for its creation.

The Cage

A typical section of Cage wall on less complicated terrain.

The Golden Cage is a massive barrier made of, if not gold, then some substance that resembles a pale and heavily polished gold. It is beautiful for a cage - covered in intricate engravings with a surface that carries the sunlight and colors around it like a canvas.

Though typically regarded as a wall - and it is, in most areas, essentially just carved and straight metal stretching above the treetops - in some places, the wall is made of many vertical levels instead. There are also areas that intersect with the land in a more welcoming way - a series of archways, a golden path. These are the areas that surround the Gates.

Function & Special Properties

The cage runs along the Astrum-Gaean and Gaean-Incaendium borders, cutting through, or climbing over, mountains and rivers as it goes. Where it intersects with a geological feature that requires movement such as rivers or streams, it will have an arch in the wall that allows that movement. If someone attempts to use these arches to pass between Realms, the wall will respond by lowering a sheet of metal that dams the water and bars the way.

The wall is, in fact, extremely responsive - almost as though it is alive. Though it does not cover the shoreline, and there is no visible section of wall in the waters of the Boundless Sea, there does appear to be a segments buried inside the seafloor, because if a person attempts to travel between Realms either swimming or by ship, a great groan will be heard, and the ground and sea will shake as a massive segment of wall emerges from the water to block their path.

Defenses

The Golden Cage is seemingly protected by some form of barrier that defends it from attacks, though it is not visible and cannot be felt when it is not in active defense.

A multi-layered section of wall working through difficult terrain.

This barrier extends far above the actual physical height of the wall - farther than anyone has managed to fly - which means there does not seem to be any means of going over the wall either.

The only known way to travel between Realms, therefore, is through one of the handful of Gates that are placed along the length of the Cage Walls.

The Gates

One of the Gates along the Cage wall.

There are several Gates distributed across the length of the Golden Cage walls, each separated from the other by hundreds or thousands of miles. As mentioned, these Gates are the only way to move between Realms; it is impossible to go directly from Incaendium to Astrum or vice versa.

That said, the Gates themselves have no security and no locks. There are no trials one must go through in order to pass through them. They can be freely traveled across at will. There is, however, a catch: the Gates are not scaled with the walls. That is to say, while the walls are extraordinarily tall and infinitely wide, the gates are only tall and wide enough for one person on horseback to pass through at a time.

Once entering the gate, a person must then pass through a tunnel - a passage through the thickness of the wall itself - before arriving at the next Realm.

This makes launching large military campaigns against another Realm extremely difficult: not only would a large force take days to travel through the bottleneck, they would also arrive on enemy territory in a trickle. This means an invaded nation would always be able to dispatch the enemy one or two people at a time, making it virtually impossible to launch a large-scale attack without a guaranteed defeat.

Gate Regions

The area around the Gates is, as discussed earlier, somewhat different than the rest of the wall - that is to say, a bit more hospitable. There are decorative golden trees and ferns, paved roads, and grand, wide staircases. Some believe these are among the most beautiful areas in Empirica Sin. That said, they are often difficult to get to, as Gates are not always placed in the most easily accessed areas - one gate is situated near the top of a mountain, for example.

Creation & Purpose

The Golden Cage was "constructed" by an unprecedented (and never repeated) alliance of powerful beings from each land in order to put a stop to the seemingly unending Caelestise-Sura War. By permanently imposing movement restrictions between Realms - and bottlenecking travel in such a pointed way, the intention was to prevent another large scale interrealm war from taking place in the future. This was successful, but the creation of the Cage did not come without cost.

As arguably the most powerful and consequential use of interacting Ability Spheres in Emprican history, the construction of the Cage required an immense sacrifice of materials, energy and unfortunately, life. Though the Creators understandably never disclosed the specifics of their "recipe", the foremost sage on the subject of power and its applications, Oriana Tansea, has suggested that it would have required the presence of multiple Metal Elementalists (already rare, see: Element Affinity), multiple Magic-users specialized in either Conjuration/Weave magic, Exchange/Transmutation magic or both, and multiple high level Psionics experts well-versed in the Creation sphere.

Other specifics necessary would vary based on what combination of creators were actually present - a metal elementalist teamed with a Creation psion and a Weaver might be able to create large swathes of wall from essentially nothing, but it would take a great deal of time and energy to produce. An Exchange specialist, on the other hand, could significantly speed the process, but at the cost of additional prepared material or even something more substantial, such as life energy.

The most pressing question - the one that most stubbornly evades understanding - is the that of the Cage's defenses. How were the responsive defenses created? Why does the Wall respond as though it is aware? How has the Cage resisted unravelling attempts by powerful Dei? The world may never know.

Or Will It?

The Secret of the Cage

The question of the Cage's efficacy and durability is actually entwined with the answer to a lesser known mystery: What, specifically, happened to Samar Kalil, the first of the Aedvectis, and the adopted mother of Peydin Kalil?

By the time of the Cage's construction, Samar had grown old - her storied life coming to a slow close. In her time as an Empirican - living specifically as a Gaean, Kalil had helped to solidify the mortals' ability to use magic. She had helped to design systems through which the potential of Void Dancers could be extended far past their natural limits - an act she saw as necessary for the continued safety and defense of Empirica Sin's most vulnerable population: the mortals.

That being the case, she chose to spend what remained of her life on the creation of this, the most powerful and effective defense Gaean could have. She allowed her life energy, her soul and her consciousness to be permanently woven into the wall itself. It is, therefore, the remnants of Samar's will that controls the actions and defenses of the wall. But there's more.

The Cage was created with a particular enchantment that allows essential invulnerability at the expense of a single extreme vulnerability - a spell that might, for example, create a fully invulnerable person who could be instantly killed with a blow to an otherwise non-vital area of the body.

In this case, the vulnerability was Samar. Her will to keep the Cage intact is what holds it intact.

For this reason, if someone attempts to uncreate the wall, they are drawn into a mental space with Samar's lingering spirit... where they must attempt to convince her to unmake the wall.