She's the leader of an organization that's mandate is "to spill the blood of the south" and wanted to a monster to kill countless people and enslave all of Thedas. The only reason she can turn against him is because she realizes Corypheus' plan will also be bad for her. If she's not a cackling villain, I'd say she's only a slight step below that.
She isn't really the leader, she's more Corypheus' lieutenant. He's the one calling the shots, and the Venatori make references to 'The Elder One' far more often than Calpernia as their true leader.
She turns against him because she realises that he isn't really there to make Tevinter better, but to make it his demonic plaything. If he betrays his most loyal followers, then how can he value the lives of the slaves and the commoners of Tevinter? She leaves Corypheus not just out of self interest, but because she realises that he is a hypocrite, and his and her goals do not align.
The proof of this is that she doesn't leave to enact her own dastardly plan, but instead with a noble objective, shared by your own companion, Dorian (Dorian approves, btw)
Thanks! I think she's a sympathetic character. In DA:I pretty much everyone was working for Corypheus, so I can't hold it against her that much. I feel like nearly everyone must have forgiven some person or group that fell for his crap. She was in a more vulnerable and sympathetic place than most. I think it'll be interesting to see how she and Dorian's views compare, if they're both featured enough to get a picture of it in the next game. A lot of their views seem the same about the value of Tevinter culture, but coming at it from totally different backgrounds. It was interesting seeing her perspective on slavery in the short story. I wonder if Dorian will have any deeper opinions on slavery once we see him again. It could be interesting to see what her wants vs what their political party wants. I hope Dorian is.. more invested in some of her concerns by the time we see him again, but I worry about their group being far less interested in the rights of slaves than I'm comfortable with after our first conversation.
It makes me disappointed to have just gotten Samson. He's got the sad story with the love letter passing, but it just isn't on the same level. It's so obvious that they had a favorite on this one. Another thought, though, both she and Dorian say something about Tevinter being the "cradle of civilization" or "where life started in Thedas", something along those lines. No love for Arlathan. I'm sure Solas is over there like, "OH COME ON", every time we talk to a vint. lol
The other thing with Samson is that we did see him in DA2, and he was a person who, while morally questionable, and not exactly sober, he was doing the right thing (helping mages in need) and doing it because he sympathised with them. Calpernia was someone we'd never met before, and that may be why she had a slightly better storyline.
Like all red templars, Corypheus used his lyrium addiction against him - though Samson was hardly unwilling to go along with the worst of Corypheus' shenanigans. Whereas Calpernia was still, in my opinion, within the confines of moral ambiguity with what she did - she only killed bad people, and only when necessary.
It's obvious that there was no way for Samson to be a part of a peaceful world after the death of Corypheus. He was gone, both his mind and whatever good there ever was. Calpernia, however, was redeemable.