Ether

((This is just a concept, and might become "harder" in terms of system strength in the future. It is based on the Khert from Unsounded.))

According to most scholars, the Ether is assumed to be the source of all magic. It is an invisible, intangible mesh of concepts (or aspects, as they are also called) that suffuses the world itself, and mirrors reality. Where there would be a fire in our world, there is a billowing cloud of fire aspects in the ether, which, in turn, can be divided up into even more conceptual aspects such as heat and light. Any being with a soul (as well as a few rare materials) can learn to manipulate the ether through magic, and so, by proxy, manipulate reality itself.

In its simplest form, magic is just moving aspects around in the local ether - taking the example of the fire, a novice mage might command and reshape the flame, or, more interestingly, transfer the heat aspects into a cup of water to heat it. Or, if they are in a plain of grass, they might borrow the sharpness aspect from the very edge of the grass around them and use it to create an invisible, cutting blade in the physical world.

Depending on the user, this manipulation of the ether can be more or less subconscious. While a guild mage would certainly think in terms of aspects, and where he could draw them from, a giant would think more about what he is trying to achieve, and his subconscious achieves the rest.

((idk how to write this but I'm also considering there to be "imaginary aspects" such as force of will, which can then be used to enhance/transmute already existing aspects, like making an existing, small flame into a fireball. But maybe they are just transmuting their lifeforce instead? of course, for that there would need to be something defined as "lifeforce". Storing aspects is also an important thing to consider, and how it would work. Could aspects be rendered "inert" for a period of time to be safely stored? Or maybe not, and that's part of the limitations that mages face. This could be used as a reason for why demons and giants can store much more magic than humans, due to them having more powerful bodies (possibly with gems or something that hold huge amount of isolated aspects --> loot from killing them?), and why people like the Lightbringers use divine artifacts to channel the power of their god, because their bodies wouldn't be able to handle it long-term. Although speaking of them, that brings up the point of incantations and why they would be used? Possibly as some kind of mantra to bring them into the right mindset or something (meditative of sorts). Because with a system like this incantation or not wouldn't really make a difference unless it affects the psyche of the caster.))