D&D 5E Tips on creating a "verge of war" campaign

[FesterJester]

So I'm DMing for a group on what I thought was going to be like a 2 or 3 shot until the real DM got back and now here I am, 6 sessions later needing to prep a broader campaign. I talked to the group and they want a 50/50 RP/crawl game. I haven't run since high school (a whooooole minute ago) and back then we most did dungeon crawl style games and I see this as a good way to flex my DM skills and do something different. But how?
So I have an idea for a game, but having never run something like this I'd like some input and ideas. You guys have been a tremendous help with my previous inquiries to the hive mind so I have high hopes for this time. (btw, for those of you who helped me figure out the whole devil and angel trapped in a room thing, my PCs totally left that dungeon before technically entering it. They explored the above ground portions, went " dungeons, we wanna know more about the goblins" and left. #fml #myplayers)
So if you have any advice for how to run a 3 nations-are-about-to-go-to-war-over-a-recently-available-piece-of-land campaign, I'd love to hear it.

This is the gist of where I'm at so far.

The city Fortress of Aberwyrnn has been claimed at different times by the Omerian Empire, Braavos and Rashillion as it sits nicely between the three. The Last War of Aberwyrnn was ended when the Dragon Gygax (for lack of a better name) descended on the city and razed the competing armies and claimed lordship over the realm. Now, it seems, the dragon is dead, having not been seen for a generation. The 3 kingdoms are preparing to march their armies forward to investigate the absence and be the first to reclaim the Keep. Our heroes (the PCs) are asked by a close and personal friend, a Paladin of St. Cuthbert, to investigate the keep prior to the 3 invasions (tri-vasion??) so as to avoid calamity and bring the clergy of St. Cuthbert to the negotiating table (gotta have first dibs on saving those souls!). As the players descend the dungeon they learn new pieces of history that reveal secrets long forgotten about each of the realms, as well as those realms backers. I've decided that each Kingdom vying for control has 1 backer (mostly there as flavor and to add verisimilitude to the world): Dwarves for Omer, Elves for Braavos, and Dragonkin for Rashillion (also the supporter hates the the next Kingdom on the list so Dwarves against Braavos, Elves against Rashillion and Dragonkin against Omer). So each time the PC's come out there is a flux of power with their arrival. I figured 3 factions (4 if you include the clergy of St. Cuthbert) is plenty. The only thing preventing war so far is A. nobodies sure who's going to go where and doesn't want to fight on 2 fronts B. they're not convinced that the Dragon isn't just lying in wait like last time and C. The thought that maybe their faction will be shown by the Cuthbert Church to be the rightful owners.

So the question is, where do I go from here? I'm not so worried about the mega dungeon (and yes, it's going to be like 8+ levels) as much as I am running the politics, which I've never done. Any help on how you write political games is going to be amazing! Thanks in advance.

 

[Quickleaf]

You've painted a good "macro" large-scale view of the game you want to run. Your immediate next step - before putting work into the details - should be to confer with your players if that's a kind of game they'd want to play. When pitching campaign ideas, I've found it best to distill your idea down to an "elevator pitch" sentence (and then if that hooks them, you can have a paragraph or a couple paragraphs of overarching description & anything the players would need to know, eg. regarding character creation).

If they're on board, then you get to drill down to details. There are many approaches you can take, but personally when dealing with factions / intrigue, I like to do faction write-ups: What is the nation's character, leadership, government, population, main imports/exports, defenses, religions, whether they finance rival adventuring parties, goals, beliefs, etc.

For example, take the Omerian Empire. Since it's a dwarven empire that, I'm presuming, is roughly equally powerful to an elven nation and dragonkin nation, that indicates to me that it's either a byzantine empire in decline OR that there are treaties/inter-marriages/religious beliefs or other factors complicating the dwarven armies moving on Aberwynn. I like the idea of a byzantine dwarven empire, one riddled with ancient dwarf-holds beneath the foothills, a curse of debauched madness afflicting increasing numbers of the aristocracy (a devil cult maybe?), and dwarven thieves' and assassins' guilds operating in the shadows to shift the balance of power.

"Our dwarves use poison." might be a tongue-in-cheek motto of one of the Omerian regiments. Perhaps the Omerian Empire, now that it's in its twilight, faces the dilemma of vassal peoples – humans, halflings, and others who were assimilated into the empire – beginning to seek greater freedoms (and greater control of their borders & taxes). So why does the Omerian Empire want Aberwynn so much? Well, war is a great way to distract the populace from trouble on the home front...doubly so if they use propaganda declaring Aberwynn a site of significance to minority races/religions within the empire...

The Omerian Emperor might observe an almost quarantine-like existence, fearing contracting the madness spreading through his lands, leading to many calling him the "Sequestered Emperor" behind closed doors. Concerned about the cost of war & rising warlords using the war as a vehicle to propel themselves to power eclipsing his own, the Emperor might finance adventurers (preferably dwarves or at least dwarf-friends) to explore Aberwynn ahead of the military invasion. A great twist would be if the dwarves find something in ruined Aberwynn which could threaten their empire's dwindling stability, such as evidence of a dwarven warlord committing genocide against the gnomes or another minority, and then try to cover it up!

More broadly, you'll also want to think about how you want to implement "verge of war" – is that going to be a narrative device you use to introduce events as you see fit, is it going to involve a countdown timer of some kind, is it going to involve a detailed victory point type system?