Anima is the natural energy resonated from the Soul. It is used to perform Soulcraft.
Anima is given off naturally by any being possessing a soul, but also exists in the environment as influence from the True Soul. Anima can be best explained as the spiritual material that makes up a Soul, and is the energy that they give off.
Soulcraft is the art of manipulating the Anima of the Soul into the real world to affect the environment in some way. It can most simply be described as "magic", but is not as simple.
All sentient creatures are capable of manipulating their Souls to perform acts of Soulcraft, and the variety of crafts are nearly limitless, ranging from energy projection to propulsion to infusion. Soulcraft can generally be used in every area in some way, and can assist in anything from everyday chores to combat.
There are different Soul types depending on the being in question, and therefore Anima will behave differently from person to person, taking on different strengths and attributes depending on the Soul.
The True Soul, being the original Soul from which all others were born, possesses the strongest and purest Anima, having power over all of Creation, governing the fundamental laws of the universe and holding influence over everything in it. However, the True Soul cannot be contained within a living being, and is instead resonated by Creation itself, acting as a catalyst for all other Souls and for Soulcraft.
The Anima of a Lord Soul is generally the strongest of all Souls that can actually be possessed by far with the possible exception of the Nephilim. The abilities granted by these Souls can govern the very fundamental laws of Creation, being closely linked to the True Soul.
The Anima of a Human's Dark Soul is the most flexible of all, being able to harness the abilities of both Light and Dark as well as being able to be neutrally attributed. This gives a Human amazing flexibility and potential as an Animage, being able to master multiple different types of Soulcraft.
The Anima of an Angel or Demon's Light Soul is more closely linked to the True Soul than the Dark Soul. This gives an Angel or Demon a distinct power difference between a Human, but lacking the flexibility of a Human's Dark Soul, they can only master one type of magic, either Light or Dark, for Angels or Demons respectively. The Light Soul consists of two aspects, belonging to Angels and Demons respectively.
The Anima of a Hybrid possesses both the flexibility of the Dark Soul and the raw power of the Light Soul, being an incredibly powerful combination, though coming at the cost of being much more unstable. Soulcraft is generally much harder for a Hybrid to master than a Human, who can learn quickly, or an Angel or Demon, who have a natural affinity for Soulcraft. A Hybrid who has mastered Soulcraft is a force to be reckoned with.
The Anima of the Soul of a Nephilim is unknown in its power an attributes. It is unknown how closely linked it is to the True Soul, and is thought by some to be a completely different entity altogether. What is known is that it holds incredible power.
The Rythulian Soul was created artificially by combining the Angel and Demon aspects of the Light Soul together in an attempt to create Nephilim, as the theory back in the time when they were created suggested that Nephilim were a direct combination of Angels and Demons. Though the Rythulians were not Nephilim, they were still among the most powerful beings in terms of Anima and Soulcraft since the Lords themselves, and indeed could rival Nephilim.