Die Mörderdame – Assassin

Since long before the comet fell, parents were using the name of Die Mörderdame to scare their children into obedience. Threats that Die Mörderdame would pay a visit to an unruly child were enough to tame all but the most stubborn youngster.

Thought by the adult population of Mordheim to be a myth, Die Mörderdame, or at least a female assassin claiming to be her, has recently appeared in the settlements that have sprung up around the Cursed City. Several high-profile individuals, including Udo from Marienburg and Reinhardt the Red, have been murdered, their bodies bearing wounds that could only be inflicted by one such as Die Mörderdame.

This is from Reaper Miniatures - where it is called Selthak Poisoner, Overlords Solo.