Sequel idea.
Before you get all excited, it's just an idea I had just now, I might write it in the future when I know what to do with it, but for now it's just something for you to think about.
It's a slight AU from what I've already written in that it'll have a wrong-boy-who-lived story line for Harry's era, so everything I've written so far up until Harry being born will be the same. The idea is the typical WBWL story with Harry's sibling getting mistaken as the killer of Voldemort and he gets pushed to the side, so Sirius decides to take Harry and adopt him as his son; so when Harry goes to Hogwarts he is an Addams and his parents have to deal with it when they find out. Harry's twin will not hate Harry but quickly rekindle their sibling bond with each other, Harry's twin easily accepting Harry as an Addams and even embracing the Addams way of life due to their twin bond, also both will be the boys-who-lived as apposed to just Harry.