The Old World is a magical place. Undead creatures, such as Zombies and Skeletons, while not commonplace, are an accepted reality. Often such creatures are controlled and employed directly by Necromancers or other evil magic-using monsters.
Skeletons, Mummies, and Zombies, as indicated in their entries, need to be controlled by a friendly Necromancer within 24 yards or by powerful Undead Champion or Hero types - irrespective of Necromancer abilities. The number of Undead which may be controlled is equal to the controller's Int. Undead Champions and Heroes do not need to be controlled themselves.
Ethereal Undead[]
Ethereal creatures are Undead wh have no material existence - although their appearance is visible in this world, they are not really a part of it. In general terms, they only exist either as apparitions or as pure energy. Gamesmasters should portray these creatures as the ghostly, uncertain images that they are, sometimes appearing substantial, at other times translucent or shadowlike or simply glowing lights. Because they are not material, they are usually immune to normal weapons and can only be harmed by magic or magical weapons. By the same token, they are often unable to exert any physical force in the material world and must rely upon magical abilities.
Ethereal creatures are subject to the rules already given for instability. An Ethereal creature is usually bound to a fixed area - often a graveyard - and will be subject to instability only if it ventures outside that area.