"Oh look, another new arrival. You'll forgive me if I sound less than enthused. Conditions down here aren't the best, and one more mouth to feed, one more potential point of conflict is the last thing we need.
Yes, everyone down in these dungeons are weasels. They should've said something about that to you on the way down, maybe it didn't register or you thought it was metaphorical. The mad king views everyone he throws in his dungeons as a weaselly traitor, so even if by some miracle we manage to escape, everyone will see what we are...at least according to his warped mentality.
...Has it really not set in for you yet? You're in here too, you're one of us now. Look down at yourself...but try not to make a big deal out of it, hmm? It gets exhausting, managing everyone's existential crisis. When you're done freaking out, follow me, we'll get you settled in..."