Typically in a vampire - themed novel like this, there could be a brooding vampire as one of the main characters. He might be an ancient vampire with a dark past. And then there could be a human who is either very curious or in some way fated to cross paths with the vampire. There might also be other vampires or vampire hunters who play important roles in the story.
I don't know specifically, but it could be a vampire and a human. Maybe a powerful vampire male and a human female.
Since I haven't read 'vampire's kiss novel', it's hard to say for sure. However, in similar vampire novels, the main characters often include a vampire with unique abilities or a special status within the vampire community. There could also be a human character who has a special gift or is just very brave and independent. Additionally, there might be a secondary character like an old vampire mentor who guides the main vampire, or a human friend of the main human character who gets involved in the vampire - related events.