Magath are spirits that are formed by the paradoxical hybridization of two (or very rarely more) spirits from entirely different choirs. The magath's actions become unpredictable and often destructive as it attempts to embody multiple irreconcilable natures simultaneously. In many cases, magath are driven mad and flee across the Gauntlet, possessing appropriate hosts as Spirit-Ridden.
Magath are most often formed when one spirit devours a spirit with a radically different nature, and in so doing, adopts its fundamental nature. Note that merely consuming a spirit from another choir is not enough to alter a spirit's nature; the nature of the concepts embodied by both spirits would have to be alien to one another to form a magath. Thus, a wolf-spirit that devoured a fear-spirit would likely become more powerful in its frightful aspect, but a car-spirit that consumed the essence of a holly-spirit might well become a magath. Barring extreme circumstances, merely associating with spirits of another choir is not enough to alter a spirit's fundamental nature, especially if the concepts embodied by the two spirits are similarly associated in the material world.
Magath that are not insane or otherwise harmful to the spirit world are quite rare, but do exist. Even so, the most benevolent or innocuous magath are often seen as anathema by the Forsaken in general and the Bone Shadows in particular.