Uncontrollable

What will happen when a young Harry escapes the hands of his relatives? What will happen when he is raised by an Azkaban-hardened Sirius? What will happen when Hogwarts sees a boy with a different upbringing and not the naive child they were expecting? He is uncontrollable and out for something that nobody but Sirius is aware of. Grey!Harry. Powerful!Harry Slowburn Harry/Ginny