Described as "an energy field created by all living things," some consider Essence as "something" that can be manipulated and used as though it were a tool.
Though essence is thought to flow through every living thing, it can only be harnessed by beings who have metaphysical access to their essence (also known as their "magical soul"). "Magic users" are able to tap into the essence to perform acts of great skill and agility as well as control and shape the world around them. Most often, this is through the use of spells. A being needs access to their own essence (small "e") in order to join it with, and use/manipulate, the Essence (capital "E") and "create" magical effects. A magic used on or against another being manipulates their essence as it relates to The Essence.
Some rituals exist, however, that deny a being access to their essence. This can be either permanent or temporary. The Corahn Ritual of Sealing, done just after birth, is an example of a permanent denial. The Seal, or brand, received on the forearm, acts as a kind of cap on a valve. However, simply removing the Seal will not reverse the denial.