'Nunc Dimittus' by Tanith Lee tells the tale of a vampire's aging servant who sets out in the mean city streets to recruit his own replacement. The title derives from a Biblical quote in Latin: Nunc dimittis servum tuum, Domine (Now dismiss Thy servant, O Lord), taken from Luke 2; 29. It was my introduction, not only to an author, whom I still admire, but served as a pre-cursor to my later enjoyment of the vampire stories of particularly Anne Rice and Poppy Z Brite, and the exotic experimentation with the concept of gender that characterized Storm Constantine's work.
Specifically, my fascination then and now, lay with the beautiful young predator Snake, who sees quick opportunities for his own insatiable appetites in the house of Princess Draculas, not quite seeing the tightening of a noose in every step he takes, regardless of direction. This character was, and remains typical of an archetype I am fond of including in my stories. In real life they might be termed 'dangerous to know, great fun to watch'.
In today's vampire fiction, of course, a character like Snake would have been the blood-drinker, but in this story, part of the twist is that he is the human.
If you are interested in tracking this story down, if only to measure it against today's flood of vampire literature, it appeared in an anthology entitled 'A gallery of Horror', edited by Charles L. Grant.