About The Soul

The soul manifests as a parallel body to the physical body. It even has "organs" of sorts. It's impervious to physical harm, but it can be harmed on a metaphysical level with specific magical techniques and artifacts. "Death" of the soul does not immediately lead to death of the body, but it still has severe consequences. It completely removes one's access to magic, and is strongly linked to a host of physical ailments and diseases.
Souls are also what separates normal humans from mages. A soul can be simplified into two layers, an "outer skin" and an "inner skin". In normal humans, the difference between the "outer" and "inner" soul is only a few millimeters up to maybe just below a centimeter in families with some magical ability. Both the "outer" and "inner" soul follow the contours of the human body. But mages have very large "outer" souls, and many magical schools teach techniques to enlarge the "outer" layer of the soul even more. This gives mages much bigger protection to all kinds of magic and energies.
The soul acts as a barrier to direct spells, by rejecting any kind of hostile spells around the soul. This means that a mage needs considerable power, time or knowledge to defeat the natural "shielding" that souls provide to say cast a death curse. But if the same mage would just use an indirect killing spell, like a gust of burning air, and the soul would not provide any protection.
The soul is also used to generate a guiding tool for cast spells. Many methods of expression rely on the soul as a start for casting a spell.
Scholars are divided on whether the soul came into being from divine influence, or whether the soul has evolved in response to ambient magic.

Type

Metaphysical, Astral