It is a "now or never" situation in a fight against world threatening demons, so most companions reason its a end justify the means situation unless you go completely against their believes.
That is not shown in a believable manner, imo. In the first chapter tension is very high and everyone is under suspicion. You witness inquisitors in-fighting with clergy of Desna, even though she is a good deity. Tieflings are persecuted simply because of their heritage. There is a nice scene with Woljif scaring some people with his shadow trick. And then it goes downhill in the next chapters.
Seelah says something about not working with hellknigths, then five minutes later she is ok with Regill in the party. Sosiel's introductory quest is about an evil necromancer, yet after one comment about the knight commander choosing the lich path, he'll chill together with the raised undead. Third chapter a succubus joins in, because Desna sais she is not evil, and no one seems to be suspicious. She just stands there in the middle of the keep and no one minds it. My lich character tells Irabeth she will sacrifice scruples and souls if she has to, and Irabeth is ok with that... I could understand Regill, because that would align with his beliefs, but she is supposed to be a paladin.
There is a dissonance between how the situation is portrayed in the beginning, and how little reaction is to an evil knight commander later on.
Some consequences come later in act 5 or rather who stayed loyal to you in the meantime. And even companions will leave you later like Sosiel will for being too much of a lich.
