I had one male vampire that fell in love with a mermaid. She did not want to leave the sea so he was racing to develop a vampire cure so that they could live in the sun together.
A vampire child was born into a “human” family. The parents broke up when she was a child. Every other week she lives in Sulani with her dad and every other with her mom in Windenburg. She plans to move to the Forgotten Hollow when she ages up. None of her parents really prioritized her needs.
I like having a vampire create a family with a sim that is not a vampire. Then I make the kids in CAS with the sim of having one vampire child and then one or two like the other parent. Sims know who their grand-parent is but after that there is no family tree connection. At that point I usually let them retire from the world. Drink a vampire cure and celebrate birthdays at a accelerated speed so that they die of old age while there still is someone in the household who knows who they are.
I have a mod that made vampire attacks happen again. Sometimes I make scary vampires that can frighten my regular sims.
Vampires are nice to have on a rotation. Then you get a break every now and then. I also mod them to age up until adults when they stop. I just got tired of YA’s and let the vampires become really well kept adults instead.