"what I'm about to tell you, Hermione is something that only the cruellest and inhuman amongst us would do, even us Demons wouldn't do it, but Voldemort did to the disgust of the world, the reason why Harry has had to deal with Voldemort twice now despite him dying years ago is because he made what is called a Horcrux or to put it simply he tore a part of his soul and put it into an item, and as long as these exist he cannot die, no matter how many times you destroy his physical body he won't stay down".