World Encyclopedia: Magic and abilities
Dherak
The power all magic draws on. Angels and Drúir carry it inside them, and it can run out.
Dherak is the word for the energy that makes magic possible. Magic draws on it every time it is used.
Ahra tries to explain it to Chris on board the ship to Déynáir, after using a little of it to dry Chris’ clothes. He ends up with an image that is easy to grasp: a battery you carry inside your chest, one that recharges itself while you sleep.
All Angels and Drúir have Dherak. Ordinary people from the normal world do not.
Magic has a cost
Every time you do magic, you use up some of your Dherak. Use too much too fast, and you become tired and empty and have to rest before you can try again. The students learn this the hard way during the island test.
Dherak can be neither created nor destroyed, says an old text. It can only be moved from place to place, and the price is always paid.
Everywhere in Anglien
According to Haltora, Dherak is not magic itself but what makes magic possible. It is not found only in people but also in stone, water and air in Anglien, and most of all in Angels and Drúir.
To Chris, it also has a smell. It is a bit like copper, and it hangs faintly over all of Déynáir, stronger around people who carry a lot of it. Read more under the sense of smell.
Spoiler (revealed in chapter 12)
When Haltora lets the new students feel their own power in the first lesson, Chris senses something far bigger than what Ahra called a battery. He describes it as an ocean. Haltora notices, and from that day on he is harder on Chris than on the others.