Mad Hettie lives as a tramp in London. In Preludes and Nocturnes, Sandman #3, she is revealed to be 247 years old, born in 1741. She was said to have hidden her heart from Death.
In Death: The High Cost of Living, she is shown to be rude, miserly, and constantly complains about the lack of knowledge that present day youth have.
She has been accused of being a witch, and also appears to have abilities as a haruspex, however she merely states that "you don't get to your two hundred and fiftieth birthday without learning a few tricks".