Spirits

Spirits are ethereal creatures, often Undead, that seem to resemble various once living beings, though whether they are actually the souls of the departed or something other is open to speculation.
  Ghosts and Poltergeists are minor spirits, whose anger and power quickly fade. The Spectre and the Banshee, however, are creatures of a far purer force. They are cursed by their own crimes, be they murder, defilement, or the violation of a sworn stricture or solemn vow, and their punishment is their imprisonment between the realms, eternally chastised by their own guilt.
  This torment soon drives them mad, and they lash out at the living with incoherent rage. The Spectre can draw away the life of a Human with a touch, whilst the Banshee can do the same with a scream. Those who survive such attacks are rarely sane afterwards.
  The Wraith is an even more powerful spirit. It too is driven to violence and insanity, but its rage is far greater. Wraiths are the spirits of great Necromancers who experimented with the blackest magic in order to acquire immortality—and failed, leaving only an echo of their identity on the Winds of Dhar they manipulated.
  To come so close to their goal yet be denied drives them instantly insane and fills them with an unimaginable hatred for the living, whose souls they take great pleasure in draining away. They carry ethereal scythes and are often confused with images of Morr—and they most certainly bring only death wherever they pass.
  To even behold a Wraith, Spectre, or Banshee can be enough to scare a mortal to death. As spirits, they are all also invisible to the naked eye and immune to mundane weapons. They can pass through all barriers and fly across the land at incredible speeds. They can thus single-handedly devastate any armies who have not already fled in terror.
  However, the force of will that keeps the spirit present means that summoning and controlling them is far from simple. Vampires prefer to use them as guards, luring them to specific locations where they will happily slaughter any trespassers. A powerful Spectre can protect an entire castle from intruders for millennia and thank his master for the constant supply of souls.
  Many Spirits are unable to stray far from their place of death, though the precise distance they can wander is enormously varied, depending on such factors as the willpower of the Spirit when alive, the number of years since its death, and how determined it is to achieve its release.
  The dead do not rest easy. The various Spirits of the dead often return to haunt the lands of the living. Some seek only release, while others hate the living with such passion that they give themselves over to evil.