Similar to a ghost
The difference between these undead and regular ghosts
is that these beings have a thin veil of darkness surrounding them. They also are not acting out of insanity but out of hatred of light and all living things.
These beings are powerless in sunlight and will flee from it.
It is said they drain a beings strength and upon killing a creature, they turn its soul into a new wraith. Resurrecting a creature is impossible until its soul which has been turned into a wraith has been destroyed.
Perception and Sensory Capabilities
Hearing, sight, can sense life energy