So in my story, the main character's mom had this boyfriend (he was this typically cliche bad boy) but they broke up and the mom obviously ended up marrying someone else via dad. But this boyfriend was stuck up on her like Snape in Harry Potter and he had a son and that son felt like his father was deprived of him because the father was heart-broken after years still and still loved 'mom'. So this son seeks revenge on 'mom' and her family. Killing basically all except for the main character- but he's out for her next.
I don't have a title for this yet, and I was thinking of a title that means when your parents' actions or past affects you. Or anyone's actions really. Like when someone's mistakes/past/actions/decisions affect someone's whole life.