17. Neville Longbottom
Neville is hugely important in shaping the entire course of Harry Potter and truly represents what is to be apure of heart Gryffindor. Longbottom, whose parents suffered dramatically at the hands of the Black family, never seeks revenge or picks a fight just for the sake of it. He knows the difference between good and bad and knows when to pick your battles. Dumbledore recognises Neville's potential through his ability to stand up for what is right, even if that means standing up to your friends, and more importantly, he also grows into a significant magical threat. Neville shapes the course for Harry, as he could have been the Chosen One too, and he saves the day in The Deathly Hallows, showing that his herbology expertise is only part of his armoury.