When Sam was six months old, his mother Mary (a retired creature hunter) was engulfed in a massive conflagration by yellow-eyed demon Azazel (one of four Princes of Hell). Her death was not premeditated, but rather a result of her incidental interruption of Azazel's visit to Sam's crib in the night – a contractual option Azazel had acquired with Mary's "consent" years before Sam was born, and which Azazel was now exercising in order to feed Sam his own demon blood to bestow him with psychic powers. Sam was saved from the ensuing housefire by his father, who then gave him to then-four-year-old Dean to carry outside, but Mary tragically died. Since that event, Dean has felt responsible for Sam and became Sam's de facto protector, largely due to their father's absence when he was away tracking Azazel.