The Essence of Life, or simply Essence is the energy that one's Soul radiates and is an extension of themselves in the Aileron series. All living things that possess a Soul naturally give off Essence, which can be used to identify a person and read their characteristics. Azmyth possesses the ability to see Essence and is capable of training others to do so as well.
Essence is the natural energy or "life force" that radiates off the Soul of living beings, such as plants, animals and guardian spirits. Essence is different and unique for each individual and can serve as a way to identify certain individuals, much like a fingerprint. A person's Soul and Essence can vary in color, size and intensity of brightness and radiance. The color of an individual's Essence is typically the same colors as that individual's eyes. A person's Essence can also shift if the individual experiences a significant enough change, becoming either weaker or stronger as a result.
Essence also plays a key factor in determining compatibility. It aids in determining if two or more individuals can have a strong connection with each other if their Souls and Essences can connect well and maintain a harmonic state. If the Essence of two Souls can attune well with each other, than their compatibility is strong whereas if the Essence of two Souls cannot attune well with each other, than their compatibility is weak and fractured.
Essence does not grant any powers or skills that can be practically used to its wielder. To those who can perceive and sense Essence, it serves as a way for them to detect nearby people or even locate and track individuals with a specific Essence.
Essence cannot be seen normally by the naked eye and can only be seen by those who possess the ability to perceive Essence. This is an ability that guardian spirits possess naturally and can teach to humans. At its most basic level, this ability simply allows individuals to see the Souls of living beings and the Essence they give off. With more training, one could focus on a single individual's Soul and read the Essence. This allows them to focus in on the Soul and Essence's unique properties and determine the individual's characteristics, personality and even intentions and morality. For example, individuals with a dark Essence are typically corrupt and immoral while individuals with a light Essence are typically altruistic and kind-hearted.