In my opinion, the Dream Guardian we have is fine, but the twist of them being the Emperor is odd (and then it turns out they were Balduran too?). If our Guardian was simply the Emperor and not Balduran, I could accept it - it'd be the reason why they know so much about the tadpole. Especially if they were just an unwilling True Soul who was unfortunately turned before being sent out to search for the Astral Prism, thus ending up in there (who has a taste in very elaborate fashion, even for a Mind Flayer). That would be far less jarring. I think it'd be good if at every meeting or just when actually entering the Prism at the Creche, the player could pass an insight or perception to see the illusion slip for a moment.
