A very rough idea I've beenbumping around in my brain. 

There lies a vampire royal family that rules over all vampires. The King and Queen have 12 children who are to be mated and the eldest son is to rule. The humans in the realm are looked down upon by vampires and are basically there for food. The other vampires are under the rule of the family but live there lives close to how we live ours in our world.  

Basically it is the life of the royal family,  their lovers, and some humans.  Anyone wanting to play king or queen just has to claim it. The eldest son will be played by yours truly. You are able to have as many characters as your u are able to handle.