Diablerie

Diablerie is an act condemned by most vampires as it involves not only drinking another vampire dry but also stealing away their very essence or soul. Those with Auspex are even able to see the diablerist's aura change after committing such an act.
To commit diablerie, the perpetrator will generally restrain their victim first in some manner. However, regardless if others help to drain the victim only one may attempt to gain the victim's power in full diablerie. Once the victim is drained dry, they may attempt to commit the final blasphemy and take their soul. The vampire must make a contest against their victim and take their very nature and power into themselves. Should they succeed this test the diablerie begins, and for this cost, they will both gain newfound power and suffer from a loss of Humanity. Should they fail this test, the body will quickly decay in Final Death. That is not the final act, however, with additional tests to be made that can cost the character their own life. Should they fail significantly during the rest of the diablerie test, the victim may take control of the vampire's body as their own. This act is the only way to lower a vampire's Generation.