Every living thing has life energy. It is used to power our magic and also allows those who are sensitive to it to locate others. Once you learn how to sense the energy you can find others. Every life energy has a signature just like each type of magic has a signature. The only thing to remember is that using too much can leave you a lifeless husk.The life force or energy of all living things can be tapped to use as a power source for the magic of Corrigenda. Usually, only the caster can tap into their own life energies unless they join a circle and pool their energies to perform complicated magics. This use is rarely used but when it is it draws equally from the pool of energies. As the circle is formed a leader is chosen to guide the energy. The leader actually risks having more energy drawn from them as they are the focus. Once the energy is depleted it takes time to renew. This is only possible through the process of rest and proper nutrition. A user of magic who abuses his body will find it harder to regain life energy. As a practitioner of magic progresses they learn their limits and how to work within them. Such as using finesse instead of brute force to achieve the same ends. There are a rare few, who learn how to tap into the life energies surrounding them. Through their senses, they can attune themselves to the passive energy of the plants and the very land where they are.
History & Usage
For the dragons, the use of life energy was as simple as breathing since it was used for flight and their ability to shapechange. They used the ability to shapechange to become members of the other races and learn from them. With the Fae, the use of life energy was a study for manipulation of the world around them. This was used to remove themselves from the material realm and protect their peoples. They never considered militaristic uses as they preferred to live in harmony with the nature around them. There are members of the Fae who enjoy using it for pranks on the other races. The majority of humans did not discover how to utilize this energy until after the "Unending War" when they began to study with the Fae. The unfortunate consequences of this is they turned this knowledge towards warfare amongst their own kind.
Depending on the race the common uses of this energy differ greatly. Though there are links to the world through the use of magic. There are many humans who prefer to try to cut themselves off from it. Those who cut themselves off from the link to the world around them do so in order to attempt to disguise their actions from others. What they do not realize is that by doing so they limit the effectiveness of their magic. Those who do not use magic tend to find it easier to remove the link though it does nothing to hide their life energies. There is one group in the Kingdom of Herigmark which has specialized in certain magics utilized in peacekeeping efforts and law. These are the Truthseeker who are employed by the crown.