Why is Death so intrigued with Liesel? What does this say about Death's character? What does it say about Liesel's character?

Death is impressed with her, as far as he is impressed with humans sees her as a "perpetual survivor." He (if death is a he) finds Liesel courageous in the face of Man's humanity. He does not want to take her but knows that he will have little choice in the matter. Death states ‘I saw the book thief three times’. This is Death's way of telling is he has been watching this girl and she is in his memory.