|“||And he shall snatch on the right hand, and be hungry; and he shall eat on the left hand, and they shall not be satisfied: they shall eat every man the flesh of his own arm...||”|
|— Isaiah 9:20, King James Bible|
Diablerie involves the consumption of another Kindred's vitae to the point of Final Death, but as the soul is consumed with the vampire's heart's blood, the vampire's destruction is absolute. Most vampires consider it a heinous act, akin to cannibalism.
The aggressor, dubbed the diablerist, automatically loses some of its Humanity and is branded by black streaks in their aura that may persist for several years. Still, the practice holds a great deal of allure, for it is said to bestow the greatest pleasure imaginable to the diablerist, greater than the Kiss, and can also grant him or her greater power.
Diablerizing the soul of a Cainite of significant age is one of the few ways of lowering one's generation, for if the victim possessed more potent blood then the diablerist's, the diablerist's Generation drops by one, possibly more if the victim was of notably lower Generation. However, there is the risk of some portion of the victim's soul living on within the diablerist. Rumors abound of diablerists taking on the mannerisms of their victims, and even stranger tales speak of the victims consuming their assailants from within and taking over their bodies. Some Antediluvians and methuselahs are believed to have survived their death in this manner.
The Traditions of the Camarilla strongly forbid the practice, but the majority of the Sabbat and Assamites consider it quite acceptable, one of the reasons both groups are viewed with such fear and disgust. While one's rank in a Path of Enlightenment may fall as a result of committing diablerie, several Paths actually encourage vampires to perform the act under the proper circumstances.
Amaranth is a small red finch from Africa, and some theorize the association with the practice of diablerie arose from the predominant color with the bird and with the drinking. Another hypothesis suggests that it comes from a red orchid traditionally sent to the future victim of diablerie, as an advance warning one week prior to the attack in antiquity and the Dark Ages. Others claim that the association with the word came from a Toreador methuselah called "Amarantha", who might have been the first victim of this foul deed.
Assamite studies of vitae have isolated the part within a vampire's blood that contains the soul. They call it "heart's blood" and it manifests as a thick, blackish liquid that quickly grows dry when it leaves the body. Via applications of Quietus, they are able to manipulate the heart's blood to allow them to diablerize a victim later. Furthermore, studies in Quietus have found a way to force the last drop of vitae within a vampire's body to calcify the heart into a semi-translucent grayish-white flask known as a "Debitum". The Debitum enshrouds the spiritual essence (the "heart's-blood") of the victim – which, if examined in detail, can be seen encased within, swimming in despair. Heart’s-blood preserved in this way endures indefinitely. If vampiric fangs pierce it, the heart reanimates, pumping a cupful of celadon-colored, aqueous, non-burning flame vaguely resembling the victim into the vampire's maw. The vampire gains all the benefits of diablerie from this. Heart's blood plays an important role in Assamite society, being used for rituals of the Path of Blood, studies of the Sorcerer and Vizier Caste and used to repay one's master in Alamut.
In gameplay terms, diablerie is rolled by draining another Kindred of blood just as he would a mortal, but continue feeding at this point. An extended Strength roll is made against a difficulty of 9. Every success inflicts one level of aggravated damage, and diablerie is complete when all health levels are attacked.
The supplement The Black Hand: A Guide to the Tal'Mahe'Ra, introduces rules for diablerie that lowers the diablerist's generation by more than one, gaining Discipline dots from Disciplines that the victim had higher than the diablerist and how the victim can possess the diablerist.