Anyone who knows me at all knows that I think of vampires as unnatural, fetid parasites, with all the connotations that brings. ("Breath of the grave." "Oh yeah, he's hot, if you think old tepid blood is, um, hot.")
So in my feverish afternoon I did come up with one idea of vampires in Amber that I liked.
See, it was all based on the "unto the third generation," line oft-quoted. What if you couldn't actually walk the Pattern after that?
Then my brain said, "No problem, that's why we keep Dworkin hooked up to the tubing. A few transfusions of the old shapeshifter's blood and we can go anywhere but this creepy dump."