Murderer

The Murderer is a Thief class male human encountered in the Spellhold Basement area. 
==Gameplay==
The game places seven of these creatures (all are identical) in locked cells that can't be opened by the party. Nor can the party see inside the cells to know if they are there.
At a specific point triggered by Jon Irenicus dialogue during the fight with him vs. the party and the assisting asylum inmates - the murderer's cell doors are opened. The dialogue corresponding to this is:
:"Here! Fight amongst the mindless assassins I would sacrifice! I shall find others to serve my needs! This place is yours! I hope it is your tomb!"
The creatures are scripted to move to the location of the party members. They move by foot and are invisible due to the MAGE01.ITM they have equipped.
As soon as a creature is within detection range of a party member, the WTASIGHT script takes over and they attack (probably from an invisible state).
In effect, this allows one single Backstab attempt. As the game only crafted these creatures as a 3rd level thief, the backstab multiplier is weak and not really a threat unless a party member is already heavily wounded. And even so, they need to actually be able to hit a party member, and their THAC0 is mediocre.
==Related Quests==
* Escaping the asylum
==Mod content==
The Sword Coast Stratagems makes some revisions to these creatures, mainly to raise their underpowered capabilities more in-line with thieves found elsewhere in BGII to scale better with the party's experience at this stage of the saga.
The murderer is now a level 7 Assassin kitted thief, with one scripted use of Poison Weapon available. It also gets 1 pip in single-weapon fighting style.
The creature is assigned a new AI script better able to execute a "backstab plan" and go invisible again after the initial attack. This will make them more effectual than the vanilla opponents are.