Oh, no no no... not a potential time paradox plotline where the previous envoy is an older version of himself.
Diedhauser striking fear into the heart of the emperor himself is proof the emperor is not the true power among the humans. He's just an imposing figurehead, as he himself admitted. I admit I mistook him for being outright evil, but his true self being this also does not absolve him for having enabled the genocidal war that he did not want.