Hexwraiths

Hexwraiths were riders who hunted the helpless for sport: huntsmen of men, slavers, cavaliers who ran down fleeing peasants and called it exercise. Now they are the hounds, not the hunters, in any way that matters: bound as Nagash's outriders, patrolling the marches of the underworlds and running down every soul that tries to slip the Great Necromancer's tally.

On the battlefield a Hexwraith charge is a horror that ignores every rule of war. The riders do not strike the enemy line: they ride through it, passing through banner, breastplate, and body like wind through wheat, and where they pass, soldiers drop with frost in their veins and their souls dragged away as trophies on invisible hooks. Fortress walls stop nothing. Shield-walls stop nothing. The only defense against Hexwraiths, the free peoples grimly note, is to be standing somewhere else.