Unquiet Horsemen are the skeleton cavalry of the Undead armies of the Vampire Counts.
In the ancient kingdoms of the Old World, and in marked contrast to the Nehekharan kingdoms further south, horsemen were comparatively rare. Most kings saw little point in maintaining battle-trained beasts, for such creatures caused additional complications in the support of an army and so only the wealthiest of warriors chose to fight from horseback.
As a result, only a few score of skeletal cavalry were available to the necromancer Heinrich Kemmler at the Battle of the Cairns, carrying their long spears for a new master.