Once a dimension purely containing energy, the Aether, in its current state, is a Conceptual Realm. It contains the impressions of everything that living beings share thoughts about. 'Fire' in the Aether can be considered the true 'Concept' of fire, a shared vision from everything that lives of what fire means to them, and the same goes for any other concept within it. Fire, Force, Anger, Life, Royalty, these concepts which permeate the Aether can be thought of as the 'shared vision' of what these things really mean, brought into being by the energy that makes up the Ethereal realm.
Conceptual Heirarchy[]
If you imagine the Aether as a vast space, with Concepts taking up a certain amount of this space, there will be concepts that take up more space than others. It's a crude idea of the Aether, given that it doesn't have any actual boundaries or 'space' as we know it to be, but it helps to imagine the heirarchy present between concepts.
The concept of Royalty, for example, is something that only humans, dwarves, elves and other sentient races that know of such a system understand. That concept will be based on the shared vision of what 'Royalty' means. However, the concept of Fire is something that almost every living being understands and knows about, a primal force that sits within the memory of almost everything. Because of that, the concept of Fire will have a much greater presence in the Aether than the concept of Royalty would, holding a greater 'domain' or 'strength'.
There are also concepts based around physical principles. The 'Concept of Gravity' might have a name given to it by sentient beings, but the concept remains the same for every living creature, as all experience it and understand that it exists.
In that regard, there is one concept that stands above all others in the heirarchy, something that no living creature with any kind of thought can escape: the concept of Transiency, the idea that nothing will last forever, that everything will eventually change or perish over the course of time. All other concepts obey this nature, and that is what makes Transiency such a powerful force.
Drawing upon the Aether[]
Trying to harness the energy of the Ethereal realm isn't anything new, and has been something attempted since the very first Era. However, when a being from the physical realm attempts to connect to a realm of pure energy/concepts, it can potentially destroy their mind and body, as well as what's around them. This was first attempted by Gilgamesh in the first Era, though the results of this were catastrophic.
The the Age of Gods, the overflow of the Aether caused by Mikhael and Vesca resulted in the creation of beings known as the Chosen, those who were bestowed certain concepts and came to embody them, causing complete havoc throughout the world. Though their bodies were a harmony of physical and conceptual, eventually their non-physical nature would overpower their form, creating incredible creatures known as Abominations. To date, the Abominations are the worst known form of drawing upon ethereal energy, as their very presence in the world warps reality itself.
In the current era, in the Age of Crystal, a stable form of this has been established as Ethereal Magic, the act of drawing upon a concept and bringing it forth with the energy provided. Unlike the Age of Gods, the Aether now only trickles through into the world, gently connecting to a select few who can then draw upon its power in a limited way. The danger of the ethereal realm is still a very real thing, however, and even a powerful Ethereal Mage's body can only handle channeling so much energy before losing their mind or body. In the worst circumstances, an Ethereal mage can end up being sucked into the Aether itself, never to return.
Relationship with The World[]
It's unknown as to how the Aether began or why it exists, but we do know that it has existed at least as long as the World has. The first time the Aether was ever introduced to what we know as 'reality' was when the ancient being Gilgamesh, who harnessed the power of the thirteen Earthen Gifts, tore through our reality to access the realm of energy, at which point it poured into reality at an incredible rate. The World, fearing what this would wrought, left that reality aside and created reality anew, leaving the old one to become both filled and consumed by the energy of the Aether.
In doing so, the Aether absorbed the first 'concepts', ideas from the sentient races of the first Era that were strong enough to influence the vastness of energy and cause it to take shapes and forms. Because of this, it formed a 'connection' to the World's reality, allowing it to seep through the barrier and continue to affect the inhabitants of The World. The Aether had grown hungry, desiring more concepts to allow it to take shape almost by instinct.
Though the details no longer exist, this process has repeated itself eight times, and each time the Aether leaves a mark on the World. Insistent in its present course, the World has been forced into its 9th Era, each time attempting to create a defense against the Ethereal energy that pursues it, and each time the Aether evolving to become more and more dangerous. Because of this, the World has hidden that which it holds most dear away, hidden in a smaller reality only barely connected to that in which it currently resides.