I couldn't stand Shadowheart because her dialogue just sounded weak... "oh poor me, I have trust issues because dark mommy doesn't love me". Then I saw the cutscene where

she stabs Lez in the throat in the middle of the night. This was shortly after Lez threatened her with a weapon drawn. Lez actually did the same thing to my main character but I just let it go. Lez and SH agreed to settle their differences in the morning but SH murdered Lez in her sleep instead. SH knows she can't beat Lez in a straight up fight and she doesn't want anyone else siding with Lez.

Such a great character moment on so many levels. She instantly went from a helpless whiner to a vicious renegade. From a RP perspective, I would want someone like that as a close friend and definitely not an enemy.