The most detailed account in the books shows pulling to be torturous both physically – like ""an iron hand pulling one's heart out between one's ribs"" – and emotionally. To Will – who was also enduring the pain of his dæmon being separated from him for the first time – it felt as bad as if he had, within his mother's earshot, asked for someone who was about to kill him ""instead to kill his mother because he didn't love her"". A permanent separation between human and dæmon kills both and releases a huge burst of energy, which, for instance, is harnessed by Lord Asriel to blast a hole between two overlapping universes at the end of "Northern Lights". The General Oblation Board initially accomplished this separation through simply tearing child and dæmon apart, but this generally resulted in the subject dying of shock.