Erase the Future (Collab with BookwormCM18)

In a world without Harry Potter, Neville Longbottom was defeated by the ruler of the world, Lord Voldemort. As the Dark Lord gains control, someone decides to take action. Traveling back in time, she tries to create a world where Harry Potter exists, but that might be hard. How to make two people who cannot be any more different even like each other, she doesn't know.