Thiefbane

ThiefBane is always (unless wished for before Sam is generated) generated in the inventory of One-Eyed Sam. THiefBane is typically generated with an enchantment, but the greater prize is the instadeath by decapacitation {need to find percent chance) on monsters with heads/necks

Being that the Black marketeer is level 24 and carrying an ascension kit, it may be difficult to kill her. However, this is not neccasary to acquire ThiefBane. If appropriately fast, armored, brave or stupid, and skilled in a proficiency capable of the Technique "Disarm", one is able to steal Thiefbane. That said, you will definately need an escape plan. SInce Sam is generated with gray dragon scale mail on a non teleport tevel, this can be tricky, however the easiest way to accompish this is to apply (break) a wand of digging, trapping her, but make sure you dont leave any items you want in those squares, or do this while near the door (blocks your escape route)