Magic

The magic system universe proposes magic as a type of matter, invisible to the naked eye, and unable to interact with materials. In the Ward Grimoire, Peter V. Brett uses the term "magical spectrum" (in relation to Wardsight), suggesting magic exists either in tandem with, or within, the electromagnetic spectrum. .

Creation and destruction
Magic emanates from the center of the earth, i.e. The Core. It is unclear if magic can be destroyed or created, like traditional matter, or if it is finite or infinite.

Magic is corroded, weakened, or destroyed by sunlight, which is why Demons are unable to stay at the surface after sunrise.

Demons
Raised deep underground, far from sunlight but close to the source of magic, demons have evolved/developed in tandem with magic use. Alagai Ka, the Mind Demon who leads Arlen, Renna, Ahmann, Sikvah, Shanjat, to the core, suggests that exposure to magic influences how the demons think, communicate, and see the world. They are able to see others' intentions, through Wardsight, and communicate with their fellow demons across massive distance, and without the use of traditional spoken language. However, only Mind and Queen demons posess the autonomy or intelligence to manipulate magic in more advanced ways.

Humans
The use of Wardsight allows individuals to see in complete darkness as easily as clear day, watch the flow of ambient magic, judge the relative power of wardings, and see the auras given off by all living things. A skilled practitioner can “Read” these auras to tell what others are feeling or thinking, and sometimes to gain a sense of their past or even their future.

Magic and emotions
There appears to be a strong relationship between human emotion and conviction, and magical power. The juxtaposition between the impersonal and selfish use of magic by demons, specifically Mind Demons, contrasts the emotionally-driven collective nature of humans.

For example, the ancient Krasian monument to fallen heroes, Sharik Hora in the Spear of Ala is particularly powerful because of the conviction with which those who died fighting demons had - a collective belief which, paired with a lack of sunlight, produced immense magical power

Warding
The power of Wards comes from their ability to "Draw" magic from a surrounding area, and re-purpose it. This has to do with the shape of the ward itself, much be unbroken and precise in order to most efficiently re-purpose magic.

Magic can be used for many purposes, for example to sharpen a weapon (Cutting Ward or Piercing Ward), to camouflage or hide (Blending Ward, or even attempt to predict future events (Prophecy Ward).