“I miscalculated, my friends, I admit it. My curse was deflected by the woman’s foolish sacrifice, and it rebounded upon myself. Aaah... pain beyond pain, my friends; nothing could have prepared me for it. I was ripped from my body, I was less than spirit, less than the meanest ghost... but still, I was alive. What I was, even I do not know... I, who have gone further than anybody along the path that leads to immortality. You know my goal - to conquer death. And now, I was tested, and it appeared that one or more of my experiments had worked... for I had not been killed, though the curse should have done it. Nevertheless, I was as powerless as the weakest creature alive, and without the means to help myself... for I had no body, and every spell that might have helped me required the use of a wand...
Harry Potter and the Goblet of Fire, Chapter 33, The Death Eaters
Hans Horcruxes räddade honom. Som Slughorn förklarar nedan.
“I don’t quite understand how that works, though, sir,” said Riddle.
His voice was carefully controlled, but Harry could sense his excitement.
“Well, you split your soul, you see,” said Slughorn, “and hide part of it in an object outside the body. Then, even if one’s body is attacked or destroyed, one cannot die, for part of the soul remains earthbound and undamaged. But of course, existence in such a form...”
Harry Potter and the Half-Blood Prince, Chapter 23, Horcruxes