When I met a badly wounded "Laz'el" in Lower City sewers in Baldur’s Gate I thought it was suspicious.. (Orin already fooled me twice before and Raphael told me I have a traitor in my camp..) So during the conversation I changed character to my trusty assassin Astarion.. and make him sneakly move near her ready to hit... but he entered the conversation! I was baffled but insisted, piked Shadow heart and casted a ranged lvl 1 holy spell (can't remember the name now.. the one that make the following attack more probable to hit). Well it killed Orin, gave SH the legendary dagger and the nether stone and started the cutscene about Orin death! Except my Tav is still in conversation with a now clearly visible Orin who behave like Laz'el and keep mocking me, than reveal herself and than vanish... So.. dk what happened and if she is considered dead or not.. but got the dagger which is nice