Add a zone or zones where pvp is disabled and where players come together to give resources to build a vampire village. The village could have shops with tiers similar to castles depending on how much the server contributes to them. This could be done by having public village hearts that you fill with blood or other resources depending on which shop the player would contribute to. Once the village is built players would be able to send 1-2 thralls to the village to work in the shops where they also may appear in real time. Either use player thralls as npc vendors for limited time or have npc friendly vampire's appear in the village. Many systems could be implemented within the village to add depth to the game's end game.