Out of the Darkness and Into the Light
From a distance, wights can easily be mistaken for any number of humanoid races. Upon closer examination, however, their true nature becomes apparent. As undead creatures, wights are nightmarish reflections of their former selves, with cruel, burning eyes set in mummified flesh over a twisted skeleton with hands that end in sharp claws.
Like all undead, wights exist on both the Prime Material and Negative Material planes simultaneously. It is this powerful link to the negative world that gives them their fearsome level-draining ability. Further, it is this draining which provides them with sustenance.
As they are not living creatures and have no rightful place in our world, many animals can sense the wight’s presence. Dogs will growl or howl with alarm, horses will refuse to enter an area which wights inhabit, and birds and insects will grow silent when the creature passes near them. In addition, their presence will gradually cause the plant life around their lairs to wither and die, marking the region as unclean.