Wraith

Wraiths are ghosts that gave in to despair. they are present in Ghost Story.

Description
Wraiths are ghosts that gave themselves up to despair and sense of self-reason. They are every dangerous, especially to fresh Shades. They devour memories which are the equivalent to life for a shade (ghost). When they eat a new Shade fresh from the world of the living with unfaded memories, they become powerful wicked creatures that could threaten mortals as well as spirits.

In the Series
In Ghost Story, a Wraith almost got Harry but Sir Stuart killed if with a memory. Lemurs attack Mortimer Lindquist's house bringing Wraiths with them as their attack dogs.