Volturi kings' siren

As much fun as it was being a sarcastic asshole, Joy was always on the lookout for more in life. After her pod was slaughtered by siren-hunting vampires, she became cold, never letting anyone in. She decided that to be safe, she had to leave the waters which she called home. Always traveling, on the move. It'd been so long since she had seen any of her kind, and while she had a few run-ins with the monsters that killed her pod, she always just ran away or ended up killing them. Many of her years after the incident were spent training, so she was quite skilled at returning the favor. It got boring and predictable, so she stopped actively seeking them out. Eventually she just stopped caring. Why worry about living and killing when she could have some fun? So instead of traveling for safety, she now traveled for the experience. Then one day she fount herself in Italy. Deciding to take a tour of the iconic "Volterra Castle" was either the best or worst decisions of her life.

I guess you'll have to read to find out.