I am playing a Dungeon World Campaign and am wondering how kingdoms are handled mechanically. Do I just let the tags arise naturally from the fiction (such as trade and supply tags/wealth tags for the "Keep" which is the closest I can see to a castle)? Or something entirely different? Your thoughts would be much appreciated!
The Steading rules don't concern themselves with creating kingdoms (or duchies, baronies, counties, marches, etc.), so they aren't the place to look for how kingdoms can become part of a campaign.
Kingdoms arise during other parts of the game. They emerge from the ideas and improvisation that everyone (players and GM) contribute to the game. There are several ways this can happen, and this isn't an exhaustive list, just examples to give you an idea:
- When you're asking questions during character creation, maybe a player responds that their bard sang in the court of King Leodric. Bam, there's a kingdom somewhere. Ask more questions (possibly from another player) to find out where that kingdom is, and draw maps to have that help shape the world.
- When the game has been running for a while and you look at your map of the world and its Steadings and their tags between sessions, and notice that these ones look like they're part of a contiguous political entity, draw a border and make a note to find out during play what duchy/kingdom/free-city league/empire/etc. it is.
- If you spontaneously introduce a king NPC during play because that's the NPC whose presence makes the most sense at that moment, then suddenly you have a kingdom somewhere (or perhaps, there was once a kingdom somewhere).
- Ditto if as a GM move you say something like “uhh… okay, suddenly the Royal Inquisition bursts into the room, followed by six of their loyal soldiers. The lead Inquisitor points at the Ranger holding the two eye-shaped rubies and demands to know what you're doing with the crown jewels.” Making the natural move for the moment inherently introduces fictional elements into the world, and this can sometimes include kingdoms.
- If you're setting up Fronts after your first session and you find your brainstorming and building off the first session leads you to creating a kingdom or king (perhaps as a Corrupt Government, Misguided Good, Power-Mad Wizard, Chosen One, Place of Power…), then you've got a kingdom.
From the other side, once you have a kingdom, mechanically very little changes. You might decide that Steadings are more likely to have oath tags to the capital of the kingdom (but you don't need to since actual kingdoms are not actually that cleanly organised). The Steading rules are slightly affected, in that when creating a Village you get to make one more choice if it's part of a kingdom or empire. Otherwise, not much changes mechanically.
Fictionally though, being part of a kingdom or other polity will change how you think about people and places. That will change how you run the game, what content you put into the GM moves you make, and how NPCs relate to each other. This will happen naturally, and since Dungeon World drives its mechanics off the campaign's developing fiction, that fiction will indirectly have mechanical effects.