The villain himself is often very memorable. He might have a complex personality, not just pure evil. Maybe he has a soft spot for his family, which makes him more three - dimensional. The main character who is becoming part of the family is also memorable as they navigate the strange new world of the villain's family. And there could be a wise old family member, like an elder, who has a lot of secrets and knowledge about the family's past and future.
Well, love might be a theme too. It could be a love that defies the expectations of the 'villain' label. Maybe the protagonist falls in love with someone in the villain's family and this love challenges the pre - conceived notions about the family. Also, power struggles within the family could be a theme. With the villain's family, there are likely to be fights for power, inheritance, or control.
One interesting plot twist could be that the main character, who initially tries to resist becoming part of the villain's family, discovers that the villain has a noble reason for their actions. For example, the villain might be trying to protect a group of people from a greater evil that the outside world doesn't understand. Another twist could be that the family itself has a secret power that the main character unlocks, changing the power dynamic not only within the family but also in the world they inhabit. And perhaps the main character realizes that they are related to the villain in a way they never expected, which adds a whole new layer of complexity to their relationship and the story.
The protagonist is usually quite interesting. They are the ones thrust into the world of the villain's family and have to navigate through all the challenges. Their journey of adaptation and trying to fit into a family with a not - so - good reputation is captivating.
The siren might start as a mysterious and somewhat menacing figure. As she gets involved with the villain's family, she could gradually soften. For example, she may develop empathy through her interactions with family members. She could also learn new values from them and start to question her own motives.