As a result of the nuclear blast, Number Six is killed, and as a Cylon her memories are automatically "downloaded" during the blast to be later resurrected, as revealed in a later episodes. For the duration of the series, Baltar is haunted by a version of Six only he can see. This woman toys with alternate explanations for her existence, from a Cylon chip in his brain sending signals, to an hallucination created out of guilt over the attacks, and thirdly to her being an Angel sent by God to watch over him, and Baltar finally assumes the latter following a medical checkup and rationalising that her extraordinary information to solve problems cannot simply be his own mind.