Khainite Assassins

Assassins are masters of a subtle and murderous magic, trained from infancy to be the chosen warriors of Khaine. They move silently and with a precision that surpasses even the standards of other Elves. Blindfolded, an Assassin can walk sure-footedly across the spears of an embattled phalanx, or strike a precise flurry of blows so that each cut exploits a different weakness of armour or flesh. 1a

The Cult of Khaine hires out its Assassins to the rulers of Naggaroth in exchange for sacrifices, wealth and political favour. Though the price is high, the Assassins' skills are such that there is a constant demand for their services. Many Assassins ply their deadly trade in the Dark Elf cities, eliminating their employer's competitors and aiding in coups against the ruling families. Some are hired by admirals of Black Arks to train Corsairs or sow terror amongst the targets of their raids. Assassins are also often employed to ensure loyalty amongst a Dreadlord's regiments. Such is an Assasin's skill at mimicry and concealment that the troops he accompanies usually remain wholly ignorant of the infiltrator within their ranks. The uncertainty this causes helps to keep rebellion to a minimum, for no Dark Elf can be absolutely certain with who he is conspiring. 1a

Assassins are masters of using poison, and they coat their weapons with a variety of toxins -- some are deadly, others paralyze or stupefy their victim. One scratch from some of these poisons is enough to send a man into agonizing paroxysms as his nerves burn, his heart explodes or his bones crack and shatter. The Assassins take great pleasure in the awful demises of their victims and can keep prisoners alive for many days. Often, they can extract confessions and information from captives much more quickly that the crude tortures used by other Naggarothi interrogators. 1a

Source

 * Warhammer Armies: Dark Elves (8th Edition) -- pg. 36