i think that what it will come down to is a really ironic twist like it will take the combined powers of all the main characters. or like Neville will end up being the one the prophecy talked about and he will win the inal battle or harry will have to sacrifice himself to kill voldemort with him now that they are linked to each other honestly there are a lot of different things that J.K. could do with it and she would probably want to keep the story rolling so there are a number of ways the battle could end but i am totally a harry potter conspiracy theorist so these ideas are always floating around in my head im nuters