Sal Lifton is the little girl of about seven, in Reaper Man, who leaves Bill Door concerned that Death's ability to hide his true nature from the human race is rapidly failing. She is the only child of the couple who run the local village pub.
Sal sees a seven-foot tall skellington where everyone else, including her parents, sees long thin Good Old Bill. She is told off for her insolence, and sent to bed loudly wailing "but it's true!"
When the pub catches fire, and Bill Door's desire to help outweighs Death's indifference to something that catches up with every human sooner or later, Bill rescues her from the flames before the boiling brandy explodes. He then gives her his lifetimer to keep her alive, thus hastening his meeting with the New Death.