The Beast
A vampire's animalistic side is called the Beast, in what is, I suspect, an attempt to demonize it by dissociation. Alas, merely giving the monstrous urge a different name is not enough to tame it. In the end the Beast always wins, I'm told. If one survives long enough as a vampire, one is forced by one's own nature to do some obscene things. And eventually, one gets acclimated to committing those atrocities and moves on to new ones, and whatever was human in that vampire dies. When the last bit of humanity in vampire dies - and once you watch enough friends, lover ones and descendants pass into the dust of ages, it does die, rest assured - then the Beast takes over once and for all. The vampire becomes an animal. If you ever reach that stage, the odds are you won't even notice when you get put down like a mad dog.
If you will is strong, and you've got a decent sense of self, you can hold out for decades. Centuries, even - I have spoken to a Kindred who is over two millennia old. But you are never, never free of the fear that the Beast will one night triumph, and that fear is what the Beast will use to bring you to bay.
Of course, the best way to fight the Beast is to keep oneself in fighting trim, and that means eating regularly. Then again, eating regularly usually means that sooner or later, you start killing kine - mortals, pardon me again - and the more Kine you kill, the easier the killing gets. So the Beast wins that way, as well. Even if you don't mean to, even if the process begins with an accident, sooner or later you get inured to the sight of a brand-new corpse that you're responsible for, lying dead at your feet. After the tenth, hundredth, thousandth or whatever corpse, it stops being a person and becomes an object, a vessel. A footnote in your history of the ages. And you, at that moment, cease to be remotely human.
