The basic premise of this world is that all doing-of-magic is the same fundamental action as the shapeshifting, just with different emphasis.
The other half of the basic premise is the seven elements - diagram, poorly organized spreadsheet. To summarize, they are:
- Tila - sky, air - freedom, movement, speed, flight, travel, language, communication; insubstantial, gaseous
- Meili - light, fire - energy, chaos, creation, destruction, vitality, perception, inspiration; forceful, radiant
- Baisa - iron, metal - lightning, forge, machine; rigid, durable, instantaneous, eternal
- Dema - earth, underworld - birth, death, life, nature, stone, matter, wood; wild, dark, solid, secret
- Kalu - night, darkness - void, absence, winter, death, sleep, mystery, the unknown; cold, dark, empty
- Lasti - water - patience, persistence, unity, immortality, travel, change, origin; liquid, mutable, essential
- Aleil - twilight - transition, reconciliation, boundary; liminal, ambiguous, between
There is a lot of overlap between elements, often neighbouring ones but sometimes unrelated or even opposed. For most conceivable purposes, there's probably at least two different ways to do the thing using different elements or combinations of elements.
In increasing order of difficulty, these are the kinds of magic you can do in this system:
Aspecting is temporarily borrowing some specific aspect (hence the name) of an element to do something with.
Aspecting is an active, conscious process; if your concentration falters, you lose whatever magic you were holding onto. This can be unfortunate if the thing you were doing with magic was "fly". But if all you want to do is cheat at hide-and-go-seek, or move small objects around, or light a candle, aspecting is really useful.
While in theory it is possible to borrow multiple aspects at once, in practice it's disproportionately difficult even from a baseline of "hold these two concepts and their elemental associations in the forefront of your mind continually while at the same time using them to accomplish effects". It's been done with two aspects of the same element, rarely, by highly skilled aspecters, and there might be some people who have briefly managed to hold two aspects of allied elements, but there isn't anyone who can hold two aspects at the same time firmly enough and for long enough to actually do anything with them. This is your introduction to the concept that combining elements is really hard.
Binding is permanently borrowing some aspect of an element, so that you can turn it on and off at will and use it casually without worrying about it cutting out on you if you get distracted. (You can also use aspects from multiple elements at a time this way, but it's still unreasonably difficult. Two is possible; three is right out.)
You tend to need a lot of practice with the specific aspect you want to bind, which is why you rarely see someone with a flight binding even though lots of people want one. Someone who has done a lot of binding can pick up the skill well enough that they only need to play with a new aspect for a few hours before they know it well enough to bind it, but having too many bindings can start to feel crowded, because they're always available in the back of your mind. Some people find just having one binding too distracting to live with.
It's possible to unbind a bound aspect, but it's harder than binding it in the first place, and rebinding is a substantially different skill from initial binding, and between the two of them most people find rebinding much harder. (I can't quite figure out how to explain the way that it's different, but it's sort of like the initial binding is you telling your brain "hey, we have this thing now" and the unbinding is you telling your brain "actually let's not have this thing", and then when you try to put it back, you're like "hey, we have this—" and your brain is like "oh yeah we USED to have that thing but we don't anymore!! I'm paying attention!!")
Subsequent unbindings and rebindings of the same aspect after the first unbind-rebind don't get harder all over again, so somebody who manages to pick up rebinding as a skill can bind and unbind pretty casually without worrying about whether they're going to want it again in ten years.
Mantling is temporarily picking up a whole element.
Paradoxically this takes less active attention than aspecting, and it makes aspecting that element much easier. If just barely being able to handle two aspects of the same element at a time isn't enough for you and you want to do complicated things, the thing you want to do is learn how to mantle. It's not worthwhile if you were only going to borrow a single aspect at a time anyway, but it's the only way you're ever going to get to manage three without having all three of them bound.
You really have to know an element pretty well in order to pick up its mantle; it's recommended that you get comfortable with several different aspects of it first, ideally without binding them because having to actively hold the aspect offers a better chance to get really familiar with it than just having it bound.
Also, holding a mantle is obvious in a way that holding an aspect isn't. You will have a kind of elemental aura hanging around you, and there might be minor physical changes, which come on gradually as you hold the mantle and revert when you let it go.
Holding two mantles at the same time is the next thing to impossible. They have a lot more elemental depth to them than mere aspects, and the interference gets pretty dire. You definitely wouldn't have any concentration left over to do things with them.
Hopefully it's obvious what the next step is: when you bind a mantle, you end up able to shift that element.
Most people who are serious about magic have at least one bound mantle (also called an elemental form); on average, it takes about three years to go from "I'm comfortably skilled at aspecting" to binding your first form, of which about six months is the time you sink into getting familiar enough with that element in particular to hold its mantle in the first place. So if you want to collect all seven, it's going to be the work of years unless you're a prodigy.
Now this is where the real fun starts: if you have more than one bound mantle, it's possible to hold two at once. And if you practice that enough, you can then bind the combination and have an elemental form that lets you casually use both elements at the same time.
Binding a two-element mantle is really difficult, and nearly everyone who has one has Aleil-and-something because Aleil is kind of the bicycle of elements - combining stuff is kind of its entire thing, so it's much easier to combine Aleil with even an opposing element than it is to combine two other elements even if they're allied. For the same reason, the only three-element form that's actually in common usage at all is Lasti-Aleil-Tila.
This post ran away with me and it's way past my bedtime so I'll stop here, with one final note: I might end up tweaking the difficulty of combining elements in various ways, because I originally wanted combined forms to be much commoner than they ended up being once I'd sorted out all the implications of my initial worldbuilding ideas.
(Ok I lied, multiple final notes: Yes, this does kind of have the same "super combo special" vibe as Threefold. I actually think I might've ramped up the difficulty of combining elements in a subconscious effort to make sure that seven-element gods weren't a thing that could reasonably ever have happened.)
(and Miresta is probably not actually the name of the world because Mirestava is the name of the conlang so logically Miresta is a country....... ok i'm done)
