What about Wyll and Mizora?
Well, personally, I saw in Wyll a certain deconstruction of the image of a "good warlock who made a pact to protect the innocent". So, in interactions with him after your party is given additional power, he accepts it without question, hinting that he's not entirely altruistic, he can also be petty and downright sadistic when it comes to exacting his revenge on the goblin who cost him his eye, lashing out at the player if they try and talk him out of it. It is possible that he can be taken to evil, like Keldorn in the BG 2.
And what about Lae'zel who thus far has given like zero signs of wanting to become nothing more than another loyal Githyanki reaver?
Reading Lae'zel's thoughts suggests that, despite her outward severity and cruelty, she is scared and uncertain. She is afraid to let her Queen down.
It seems to me that at some point the player will have the opportunity to reveal the secret of Vlaakith by changing Lae'zel's opinion of the githyanki and their goals.
For some reason I think she might even join Sha'sal Khou, become more tolerant or something.
