All men and women have secrets. Desires wear away self-control, and one's holding back slowly gives way, and a dam-burst of vice is the result.
Mellamy will listen to you. Mellamy will absolve your sins. She smiles, takes your hand, and for one last night, those whom she blesses indulge themselves as they see fit, be it in gambling, drink, drugs, sex, or violence, until they pass out from exhaustion. When the sun rises again on them, their sins seem distant and far away, and the concept of indulging again, just a little, is foreign to them. One can simply no longer understad the appeal, and can no longer bring themselves to participate: alcohol and drugs may poison from overdose, but the poor fellow will be clear-headed throughout, and dice will not favor him.
As a consequence of this shortcut, though, one's self-control in other matters wanes, and many of those who call upon her once to force them to behave will find themselves wanting her aid again, to restrain this new hunger that has sprung up inside of them (in game terms, each application of this permanently reduces the target's Temperance by 1).
Mellamy appears as a lovely, tempting young woman with ruddy hair and grey eyes, dressed in argent sheets and veils that never truly reveal, but hit at what must lay beneath. She may take other forms, though this is her favorite, and no matter what shape she wears, she may be picked out by her necklace of clam-shells, and with every vice she steals, one of them opens and births a Pearl Child.