so umm, for clarification what would be the responsibilities of the Dungeon Master compared to an animal trainer in your system?
I'm thinking of making "normal" animal training and even exotic taming a pre-requisite to gaining the Dungeon Master.
Dungeon Master would be an "uplifted" normal dwarf who is the best exotic tamer in the fort, rather than an immigrant noble, whose uplift would occur as part of a special "mood" style event. Triggering this would require special pre-requisites.
Upon hitting this upgrade, they will leave for a while, and come back as a Dungeon Master, with new menu functionality, in the same way that a manager lets you set workshop profiles when appointed, or brokers let you see the value of your fortress production. The functionality of a DM, however, would be more specialized and not strictly necessary for running a basic fortress, probably dealing more specifically with how breeding, taming, or training is handled from a more abstract and high-level way, or else giving specific breeding instructions (as in, making specific males more likely to breed with the females of their species in order to encourage specific traits).
DMs might also carry specific other benefits, like going out into the wild, and taming a wild animal from a biome region a few regions away from the fort itself, possibly bringing back an animal that the fortress otherwise would not have access to, and giving the fortress the ability to breed and semi-domesticate them. Maybe players could have an option to encourage the DMs to go out and try again to tame more wild animals, as well, instead of just staying in the fort.
More generally, what I see could occur with nobles is something vaguely related to the notion that the game should start out simple, and get more complex, rather than slamming the player straight into a learning cliff by throwing everything in their face all at once, and leaving it to them to figure it all out.
Games like Mount and Blade handle the "informal tutorial" of the game by having more and more complex aspects of the game become available to players as they become more wealthy and powerful. At first, you can hardly do more than struggle to survive against bandits, but you learn how to handle that, and gain more money. Then, you can start learning how the economics of the game works when you gain the ability to start investing in businesses or incorporating trade between towns into your ambling between towns as you can afford more and more pack mules. You learn how the politics of the game works only after you have acquired enough status and power that the nobles in the game actually start taking notice of you, and allowing you into their inner circle. You never see the aspects of the game that relate to management of towns or villages until you actually own one, and the politics of the game only kicks into full gear when you're actually influential enough to actually start turning the tides of wars or outright carving out your own personal kingdom.
The game has a natural progression of complexity and difficulty in balancing all the complex forces vying against one another because complex parts of the game are simply out of reach of the player at the time they start the game. You can see armies marching across the maps at the beginning, but the armies don't care about you, and you're not powerful enough to significantly influence a major conflict, anyway.
Pushing more advanced game elements onto pre-requisites to expanding your fortress (as per
Class Warfare) changes the dynamic of the game into one where complexity is introduced to the player gradually, and at the player's own pace of comprehension.
This would mean that more complex aspects of animal husbandry, for example, would be hidden from view until the player proved they were both interested in and capable of large-scale animal taming and breeding.
Expanding this principle into further nobles that activate different advanced features (that are not implemented yet) of gameplay, such as hypothetically having a general noble requirement for pushing armies across the map when we get the army arc in, or a "barkeep association master" of some sort for advanced functions of the upcoming taverns would provide a gameplay function of shielding a new player from some of the information overload as more complex parts of the game get added in as the game develops.
In some sense, they wouldn't have much direct responsibility, the way that brokers or managers or Chief Medical Dwarf function now - they do specific things at specific times, but they also just passively enable new functions of the interface simply for existing. (Maybe the Dungeon Master is the specific noble who is directly responsible for the import/export of creature knowledge, as had been previously suggested. Plus they can do that "go on a journey to tame new creatures" thing, although that leaves their other functions temporarily disabled.)
Honestly, I think that having a straight-up "Beast Master" that you just call a Dungeon Master and give some of the dungeon master flavor (tendency to wear cloaks) would be fine. The short-lived confusion that having a "Beast Master" named a Dungeon Master might give newer players would be worth the nostalgia bonus and D&D reference.