Buckle in, because this is gonna be quite the long and meandering post.
Last month, there were a lot of questions from my writing group about how the magic system in my books works. So, I've been doing a lot of thinking and workshopping how exactly somebody can throw a fireball or turn into a wolf.
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Part one: power.
Where does the magical energy come from, and how do humanoids manipulate it? The answer requires a basic understanding of the theology/metaphysics of Natris. (The planet my book is set on)
Any and all forms of magic originate from the Veil, a barrier that separates the observable universe (reality) from Abdonya and Encore (hell and heaven). The Veil can best be described as the power of creation and change. Power is drawn through the Veil via access to a khar, a spirit. There are several main types, along with an enormous number of subtypes that I don't have the time to list. Firstly, there are divine khar, which are less powerful and more varied versions of the seven gods; the Lord of Day, the Lady of Night, the Lord of Storms, the Lady of Flames, the Mother Below, the Father Above, and Leviathan. Secondly, there are demons. Demons all have unique names and temperaments, whereas a divine khar will only have a name if it is a direct creation of one of the gods. Lastly, there are the khar of dead animals. These are much more common however, they yield much less power to the user.
These three main types connect to the Veil in two different ways: demons and divine khar have an inherent connection due to their supernatural nature, and the khar of animals can only connect to the Veil once said animal has died. Even then, they are not fully connected to the Veil. An animal must be bonded to a person in order to completely merge with the Veil. Otherwise, you have the small chance of being able to see the apparition of said animal near the place that it died.
But how, you may be asking, does somebody use the magic? And what happens when they use it?
Well, I will answer that question with the last part of this post. A human - or other intelligent species - can touch the Veil and use magic if, and only if, they are bonded to a khar in a similar way to the spren bond in Stormlight. Except without the oaths, armor, and blade. What kind of magic they use is dependent on what kind of spirit they are bonded to.
For example, if someone were bonded to a divine khar, they would be able to manipulate things that that khar is relevant to, such as fire, the sun, shadows, storms, the sea, time, or flora. Someone bonded to a nature khar, however, would do much different things. Take a wolf, as an example. A person bonded to a wolf would take on wolf-like behaviors and features, to a certain extent. Their senses of smell, hearing, and sight would be enhanced to those of a wolf, their hair would go from it's natural color to gray and their eyes would take on a yellow-golden hue. A person would also take on some of the behaviors of a wolf, such as becoming far better at working with, shall I say, a pack. These changes - save for being able to transform into a wolf - are, also, genetic, and therefore are passed down. Genetic changes and traits such as these are the reason certain great houses and clans are associated with certains animals.
There are built-in limits to the magic system, but that - and what being bonded to a divine khar or a demon entails - is for another post.