How to kill an Ardat-Yakshi

It's quite simple really... sneak up from behind when somebody else is trying to kill her and shoot three bursts to the head, or use two to three proximity mines, its really that simple. Whatever You do... don't ever, ever try to fight head on with an Ardat-Yakshi.
So yes my players had an encounter with an Ardat-Yakshi. Of course they did not fight her directly. It came to a standoff between the witch and asari commandos that were pursuing her and the decision of the players would tip the scales in favor of her or the hunters. The choice was not easy since they did not know her for what she really was, at least they were not sure. Needless to say Aryah (that was her name) was very powerfull and had a unique skill set ranging from manipulation to poison making. The group was under the influence of hallex for most of the encounter, so it was hard for them to deny her help that she was asking for. Her plan was to escape her perusers and with the assistance of the players get into a corporate controlled base to which the commandos had no access. There she could resume her killing spree. Thankfully the turian Tremorius a military veteran had a moment of clarity and at the last moment he decided to put Aryah down .