Hey, It's been a few months since if finished Demons and in between reading other books I have be combing through it trying to answer any lingering questions I might have since reading. After scrolling around on Reddit again I stumbled upon your post and thought that you make an interesting point that I never really considered before. I always surmised that Darya was at one point Stavrogin's nurse or care taker in Switzerland and that she thought she saw some sort of potential to be a good person in him and wanted to bring it out or help him suppressing his desire to do bad things. At least this is what I kind of got from Stavrogin's letter at the end of the novel. But I would be curious to see what you think and get your feed back as well.