Kazarak limitations
From LSWiki
A number of disadvantages are apparent from the bond between the Kazar and the host body. One of the most severe is that the process is completely irreversible. Once a host body has been taken over by the Kazar, nothing can retrieve the original life-force and bring the body back to normal. The host body will eternally be a bound servant of the Kazar demons.
A second disadvantage, probably the most disconcerting to those newly-bound by the Kazar, is the fact that no natural healing or rest will restore their bodies. Kazarak can rest for any length of time with no appreciable benefit. Many magical and mundane methods of bodily healing work either to a lesser degree, or not at all on a kazarak. The kazarak is entirely dependent upon their possessing demon for all regenerative functions.
The complex construct of geoturgic runes that surrounds the body of a kazarak interferes with the operation of many magical protections and auras, rendering them useless or completely unusable for the kazarak.
Since the essence of a kazarak is comprised of an energy-channeling demon, many forms of damage that deal with the control and application of magical energies affect kazarak differently than most targets. While the kazarak may be able to siphon off some incoming energy for their own use, it is equally likely that the attack will disrupt the link between host and Kazar, causing much more severe damage than would normally be expected.