[Kraven de Sade]

The essences? I'm guessing you mean the characters themselves, rather than the stories built up around them?

It's been a while since I've read Dracula, but what I got off of it was that Dracula was desperate for change, but, despite his available resources, he was incapable of change, no matter how hard he tried. Basically, he was Dracula, as depicted, no more, no less, and that is all he would ever be.

Lestat could change with ease, though at first it was forced upon him. But after that, change was a simple matter. More importantly, he could force those around him to change to meet his needs and growing ambitions (when necessary). He became the perfect immortal... unbound to the world, and therefore capable of adapting to new situations. He embodied the very evolution of humanity, and used that to his advantage.

Louis, on the other hand, while capable of adaptation, found adaptation superfluous. He always existed in the shadows, both literally and figuratively. One living in such a state as he could easily watch the ebbs and flows of human society while remaining apart from it while simultaneously avoiding its notice.