Alright, fair enough. I do like the idea of having different methods. It could lead to a nice "preference based" market for how you own your slaves.

The idea I had for the character who is already a slave, was that he had been bonded to the family for generations, perhaps even since the initial enslavement of vampires. At first he resisted like anyone else, and was forced into it with starvation. Maybe the bond with his first master or two in the family was of the more invasive, and then as he became more docile, he became more of an adviser and butler to the his later masters.