Many Necromancers and liche-lords have risen to kingship over the Undead, becoming so saturated with evil power that their physical forms radiate magic. Some Vampires actively seek out the citadels of those lords who have gone before, hoping to take possession of their remains and use them against the living. No mere casket or hearse could be fit to bear the remains of one of these masters of the night. Instead, they are enshrined within a Mortis Engine, a cage of fused bone, surrounded by trappings of grandeur and borne to war by a host of spirits bound to the infernal device. Though all that remains of their evil sovereign may be a wizened skull or a gilded finger bone, these spirits are forced to protect the unhallowed remains for the rest of eternity. The evil soul that clings to the unholy relic attracts the attentions of wailing Tomb Banshees, who shriek and howl in the air above the grotesque hearse. The Mortis Engines are watched over by deathless attendants known as Corpsemasters, trusted servants of the Vampire Counts who have proven immune to the dire energies that emanate from the relics within.
When the Corpsemaster removes the locks and opens the lead-lined reliquary, the deadly artefact inside can be held aloft, stealing life energy from the enemy and energising nearby Undead. The longer a battle rages, the more energies the relic absorbs, and the more powerful it becomes. Mortis Engines can usually be found where the fighting is thickest, drifting ominously near to the battle line where their power is needed most. However, so redolent with Dark Magic are these artefacts that opening the reliquary is not without risk - its power can sometimes tear apart the engine itself. Indeed, if such a dread relic is ever shattered upon the field of battle, the subsequent release of pure evil has been known to smite everything in the vicinity, living or Undead, in a wave of destructive Dark Magic. Some reliquaries also carry blasphemous tomes to battle, or scrolls of parchment rumoured to have been penned by Nagash himself. Oftentimes the winds of magic become nigh uncontrollable when such a fell tome is near. Heavy with evil magics, painstakingly illuminated with such care that their creator's souls have passed into the leaves of human skin that form its pages, these books can be a boon to the twisted practitioners of necromancy, but also the bane of reckless and unwary spellcasters.
- Warhammer Armies: Vampire Counts (8th Edition), Needs Citation