I was thinking, you know, if we were going to have a vampire walk this American landscape, well what if it was a new species of vampire? And it sort of hit me then. What if it really was a new breed with new powers and new characteristics and what if the vampire bloodline every once in a while mutates or evolves as it hits somebody new? Then it hit me that this is a story about an American vampire that was born in the Old West and he has these sort of confounding powers to the old guard and from there it bloomed into this idea of vampire genealogy and evolution throughout history, all the way back to pre-modern times.