How much of Duncan's loyalty is still a choice?
Thinking about Frank's six novels here.
In the first book, Duncan's loyalty is fairly easy to understand. He serves the Atreides and dies protecting Paul and Jessica. By the later books, I find it much harder to feel good about people describing him as loyal.
Hayt is returned to Paul as part of a plot against him. Recovering Duncan's identity involves resisting the purpose he was created for. Under Leto II, another Duncan can be ordered whenever the previous one dies, and the new arrival has to confront what Atreides rule has become. His objections barely interrupt the arrangement.
Then the later factions all have their own reasons to want a Duncan, with training and conditioning intended to make him useful to them.
What bothers me is how often people want the man they remember, or the qualities attached to his name, without giving much weight to what this particular Duncan wants. Even affection can become another reason to keep bringing him back.
That makes his resistance increasingly important to me. Do you read it as loyalty to the original Atreides values, or as Duncan gradually finding reasons to live beyond service to anyone else's project?