Interesting thread. I'd like to see this discussion continue as I enjoy giving the players the ability to shape the world around them and in 5e they get tons of gold and there's not a lot they can do with it. With the right rules set up for something like this, you could run a great political campaign or a game-of-thrones type deal, or have the PCs inherit kingdoms and play as their descendents, etc.
Some specific ideas...
- CHARGE Combine Knights with a Warhorse for a heavy cavalry unit
- Location, Location, Location - This begs for a big hex-based map. Assign resource values to specific hexes, assuming you have commoners laboring there. You could get as granular as you wanted (wood, food, etc) or just do a generic gold value. Perhaps allow the construction of a building provide "ownership" to hexes within a certain radius (with more expensive buildings like castles extending the zone of control), and if those hexes are attacked, the guards at the building are the ones who respond, you could use the skirmish rules but honestly I would probably favor something simpler for most combats that don't involve the PCs, but I'm not positive yet.
- Build it and they will come - Some other ideas for simple buildings would be guard towers, stables, and mines.
- Nice guys once you get to know them - In addition to their named purpose, Bandits, Thugs, and Bandit Captains can also be used to represent militia.
- You're a wizard, Harry - The evil mage statblock from Lost Mines could be used to represent a low-level mage.
- Manifest Destiny, Mother****ers - The PCs might discover an indigenous population that could be leveraged for cheap labor or made equal partners, or maybe they know something about the surrounding terrain. Even if the PCs don't kill or enslave them, these creatures might come to resent their presence and stage an uprising or a rebellion when the party least expects it.
- I know a guy - PCs could borrow money to build stuff, but have to pay it back (with interest). This could open some interesting opportunities for the players to, for example, borrow money to construct an outpost near a valuable mineral deposit (cave or something), sinking a ton of borrowed gold into its construction only to discover that there's a chromatic dragon nearby that doesn't like them getting so close to his lair, so he torches the outpost unless the PCs stop him. If they fail to stop the attacks, they're on the hook for the borrowed money but have no way to pay it back (cue an adventure) and your interplanar loan sharks start sending increasingly powerful interplanar debt collectors after them (maybe a pit fiend named Vinny).
- You gotta spend money to make money Many players, when presented with the above option of borrowing money, will elect to "play it safe" and pay out of pocket for everything. To make it more realistic, make sure there are consequences if they don't act quickly on information (a rival team moves in and takes ownership of the land, for instance), so they are more tempted to borrow money in order to seize an opportunity before they lose it.
- Best of the Best Sir! With Honors! You could rather easily create upgraded versions of the stock NPC statblocks to represent more elite units (that are more expensive to train, maintain, etc)
- Behind every great man... Optionally provide the PCs with NPC advisors, a "cabinet" if you will, to advise them on various courses of action. They would have expertise in a specific area, but also their own motives. Make sure any NPC you put as an advisor to the PC has a full set of bonds, traits, ideals, and a few skeletons in the closet. The goal should be that, most of the time, the NPCs are providing valuable advice and insight, but every now and then, due to something going on behind the scenes, the NPC might advise something that isn't strictly in the best interests of the PCs. For example:
Moe the Mining Consultant - Moe can oversee a surveying team that gets sent to a recently discovered hex, and a month later he can estimate how much gold the hex is worth if you were to mine it, as well as any dangers from doing so. Moe is good at his job and loves the PCs ever since they saved him from the kobolds in the mine, but his wife is the daughter of major crimelord with various interests of his own. The PCs discover a hex that is worth double or triple the normal value, but Moe's father in law has already "staked it out", so Moe claims that the vein is less lucrative and kicks back some of the earnings to the family. If the PCs ever visit the hex, they will see something is off, or maybe if this happens a few times, the treasurer begins to notice inconsistencies in the accounts and tells the PCs that he thinks Moe is swindling them. This leads to interesting conflict and RP opportunities that could go a bunch of different ways, driving adventure on the micro and macro level!
- You can't take the sky from me - Griffons, Wyvern Riders, the sky is literally the limit. When it was still under the control of the Zulkirs, Thay had a large division of elite griffon riders that were trained as Warmages and used as scouts and to support land units.
- I am become DEATH, destroyer of worlds! Undead are a lot more useful in this perspective since they don't cost money to feed, but many of them move very slowly due to vulnerability to daylight unless they're in dark tunnels or a swamp or something. Take a page from the Thayans and have laboratories where you can experiment with and develop new forms of undead. Maybe your PCs won't, but their neighbors might!
- These boots were made for walking... Get inspired by the Ranger's favored terrain and maybe give creatures that are native to a specific region various advantages or faster movement.
- Oh.... the Weather Outside is Frightful... Modify movement, production, food consumption and production based on the season. Basically production grinds to a halt when it snows or something.
- Bandits? We prefer to call ourselves "privateers". - Mercenary companies for hire. With Ogres. Including Hobgoblins, Orcs, Goblinoids, etc. Hire them to harass neighbors.
- Gonna be a baller, a shot caller... Once you're really high level, you would basically be functioning as a patron for other adventurers, thus you could hire minion adventurers to quest on your behalf. For example, the above-mentioned mining operation is threatened by a young dragon, but you're level 19, not worth your time. Hire some adventurers to go and save the village! Make a table that randomly determines which adventurers are available to be hired on a given day/week/month. You could retain the services of an adventurer for a longer period of time, maybe to be the governor of a town. There's gotta be a chance that the adventurer flakes out and goes to do something random, as adventurers are wont to do. Perhaps a rival convinces the adventurer that you're an evil despot that must be dethroned! Suddenly you're defending your castle from these pesky self-righteous adventurers...
- The Truth? You can't HANDLE the truth! The PCs should be asked to sit in judgment over community events and disagreements, over land, resource allocation, maybe the guards are being jerks to the populace but you need them because your outpost is next to a bunch of cannibalistic elves. The decisions should have consequences.
- In today's news You've GOTTA have random events. Famines, earthquakes, plagues, a freak magical phenomenon, discovering a previously unknown gold mine in your borders, usurpers claiming to be the TRUE leader of your kingdom, refugees from an interplanar conflict, Tiamat being summoned by cultists at an ancient site that turns out to be about 4 miles away from your newest village, the discovery of an ancient artifact of evil with dire portents for the future (like the one ring), an ancient prophecy, Drow raids from the underdark.
- Diplomatic Immunity - The PCs should definitely be able to hire and use spies to learn what's happening in neighboring areas, as well as scouts, of course.
Just a few thoughts.
