Hellflayers of Slaanesh

The Dark Prince of Chaos prides himself on the splendour of his decadent realm. Alas, the constant warfare and anarchy that so defines the Realm of Chaos has ever worked against Slaanesh’s pursuit of perfection by leaving battle-slain corpses littered across his lands like the petals of a particularly repulsive plant. Thus do the Hellflayers ride hither and yon across the alabaster plains, their reaping blades cutting and slicing the distaff flesh into small pieces that Slaanesh’s otherworldly flora can easily devour.

Of course, Daemonettes being the preening and selfish creatures they are, the menial work of tending and feeding their lord’s garden is a weighty chore. There are no emotions to feed upon in such a task; no tortured and amplified sensations to sample. Without such things, Daemonettes grow lethargic, and their forms can even start to dissipate. So it was that for a time that only those creatures who had displeased mighty Slaanesh were sent to crew his Hellflayers, there to while away the millennia serving the bloody harvest.

Yet if Daemonettes are cruel, they are also wily. It wasn’t long before a particularly willful pair defied their master, and brought their Hellflayer not to the battle’s aftermath, but to its gory height. Within moments, blades prepared for rotting corpses proved just as keen when set upon living flesh. Severed heads and limbs flew like chaffed wheat; daemonic ichor spattered across the Hellflayer’s steeds and crew. Yet all this went unnoticed by the Daemonettes, for they were gripped by a battle-rapture they had never known. Like all things sprung from Slaanesh’s spiteful land, the metal from which the Hellflayer had been forged was deeply attuned to the sensations of the living. As its blades sank into flesh, each victim’s every suffering was transmuted into a spiritual incense so intoxicating that it drove the Daemonettes into an impassioned frenzy, magnifying their speed until their strikes became so swift that no eye could follow them.

When Slaanesh learnt what had transpired, he was angered, for no Chaos God easily tolerates flouted authority, "iet he was also pleased, for that lone Hellflayer had wrought much carnage — Slaanesh’s armies have ever been weaker than those of his dark brothers, and anything to alter the balance was cause for delight. So it was that the D ark Prince decreed that to ride a Hellflayer would no longer be a punishment, but an honoured station of war. Ever since, Hellflayers have driven in the vanguard, blades mangling and maiming foes caught in their path. As for the two rebellious Daemonettes, Slaanesh transmuted them into unfeeling marble and set them on the far end o f his causeway, their backs forever to the decadent glories they had once known and enjoyed. The accursed ones stand, even to this day; a silent reminder to all the D ark Prince’s followers of what happens to those who would dare flout his will.

Source

 * Warhammer Armies: Daemons of Chaos (8th Edition) -- pg. 54