ChangXi

I actually got surprised myself on another playthrough just yesterday where I was doing pure evil, but she decided to spare the nightsong anyway, which didn’t happen last time I did an evil playthrough. Maybe it’s random in some way, or maybe there’s a dialogue you need to have during some point that I missed this playthrough. I do know if you destroy the grove she becomes clearly upset about it during the party in camp, but I neglected to speak to Shadowheart almost entirely this playthrough so it’s possible I missed some dialogue trigger. I’m not sure myself now

Fun fact about the companion quests, what descisions you make as the player will change what your companions do if you let them make their own descisions. For example, if you side with the goblins and destroy the grove then Shadowheart will actually not reject Shar if you let her make her own decision.