Okay so the Karlach quest comes down to do I believe Karlach that the servants of Tyr are actually a cult working in the service of a devil or do I believe that the (supposed) servants of Tyr are right that Karlach murdered a household without provocation.
I should be able to use detect thoughts, tadpole, sense motive, detect lies or something other than "I guess I gotta believe someone".
Also, last I heard, Detect Thoughts hadn't been implemented yet. But there's also a passive Religion roll I failed in that conversation. I'm GUESSING that it has to do with the fact that
demons and devils don't ever work together so their assertion that a "devil" is working with gnolls (demons) is a bit suspect.
