Question: how did neville get the sword of gryffindor to kill nagini?
Answer: So how does Neville pull the sword from the Sorting Hat during the Battle of Hogwarts? ... The sword was truly Gryffindor's and he didn't steal it … Its first allegiance always was to a worthy Gryffindor, and it was going to come back when someone really, really needed it. And it came back to Neville.”