Cauldrons of Blood

The Cauldrons of Blood are rumored to be gifts from Khaine, who bestowed them upon the Witch Elves as rewards for their single-minded dedication to his cause -- at least that was Morathi's claim when she gave the first of these to brass cauldrons to the Cult of Khaine. Each is kept filled with the blood of countless sacrificial victims, though curiously, it never overflows. The cauldron always maintains the same level, no matter how many gallons of lifeblood are poured into it, as though the very metal of the cauldron thirsts.

Each Cauldron of Blood lies heavy with dark enchantments and, with the proper knowledge, a Death Hag can access these to unleash the many blessings of Khaine. Chief of these is the cauldron's ability to restore youth and vitality to those who bathe within it. As Morathi kept the innermost secrets of the cauldron to herself, all others who utilize this blessing must frequently repeat the bathing process or soon find themselves in their old and withered states once more. In this way, the Hag Sorceress ensures the Witch Elves' loyalty -- with the irresistible lure of eternal beauty.

The Cauldrons of Blood are ordinarily kept safely secured within the great temples of Khaine, but one is occasionally brought forth when a great host of Witch Elves marches to battle. Drawn to the cauldron by the prospect of slaughter, the Lord of Murder's baleful spirit goads nearby Dark Elves to a feverish war-lust that will be spent only when there is no longer any blood to spill.

Source

 * Warhammer Armies: Dark Elves (8th Edition) -- Page 47.