Introduction
Long ago, I decided that I wanted my games to be as far as possible from murderhobo campaigns. I set things up so the party would be stationed in a single place and work to build a civilization. It has worked amazingly well for over 15 years, generating great stories and games that players remember fondly. I strongly recommend running sandbox-style games where the PCs build, support, and manage tribes, cities, and empires. I know that I'm not the only GM or gaming group that does this, but it's still a minority play style, and I want to make it more popular.
Here's a brief list of campaign ideas, with a variety of tones and alignments, that fit this pattern:
1) A tribe of savages in a wilderness area has recently been converted to the worship of a civilized god, and a local power broker has hired the party to assist and guide them.
2) Due to the recent death of a powerful monster, new lands are available for settling, and the party members (and possibly their family and friends) are pioneers.
3) A war has recently ended with a peace treaty that gives independence to the contested area, and sets it aside as a new multi-species country that accepts immigrants and war refugees.
4) The region (or world) is doomed by something coming many years in the future unless enough nations can be united to prepare a defense. The party is the chosen heroes who must accomplish this.
5) The party has been assigned to govern a poor and rebellious province beset by monsters and enemies.
6) Existing civilizations are crumbling into ruin and decadence, and the party has sworn an oath to each other to carve out a new empire for themselves.
Any GM can run a civilization-building game just by deciding to do it, and it will probably work well. All you need is for the group to have a shared desire to make this kind of story happen. Even if you are a new GM, and have only run modules and published adventures, you can still run a civilization-building game by following these guidelines. Most existing modules can easily be adapted to this game style, and the civilization building is the grand narrative that ties it all together.
I did not start by making civ-building rules and following them. I evolved the game style over time, adding innovations to nudge the gameplay in better directions. I am sharing these with you, so you will have less trial and error.
Claiming Real Estate
In a typical RPG, the party will clear the monsters out of some location, take any valuable loot they can carry, and then leave. It's rarely discussed what will happen after they leave, but it's often assumed that a new group of monsters will move in and repeat the cycle.
In a civilization-building RPG, any dungeon or wilderness location that the party clears becomes a real estate property that they own. After the party claims a property, they can work to develop it into a site. Usually this involves spending resources to fix the property up, convincing an appropriate allied population to move in, and putting an allied NPC in charge.
The map starts with a small area surrounded by monsters, wilderness, and/or rival civs, but over the course of the game, if things go well, it turns into a large, well-developed civilization controlled by the players.
Collaborative Mapping
In a typical RPG, the map is an optional piece of fluff, but when the party is building a civilization, it is central to the game. The characters are literally rewriting the map every other session. The overarching goal of the game is to change that map and make it better (from the character's point of view). When the game is going well, the players will argue over how they should change the map, they will expend effort and resources to add new things to the map, and they will go on quests to claim control of parts of it from monsters and NPCs. Your job is to encourage this behavior.
A good GM follows the way of the Tao. This is especially true when making your campaign map at the start of the game. The best way to make a map is to not make a map. Just start with one or two places and a blank piece of paper, explain the campaign idea, and tell your players that the rest of the map will be filled out based on the identity and backstory of their characters.
For example, in my longest running game, the map started with just two places: a tribe of kobolds that had recently been converted to the worship of Bahamut, and an elf city with a patron who gave the party the mission to help them out. The players filled in the rest. One was a wizard, so we put a wizard university on the map that he named and described. Two others were elves from different societies, so those got added to the map, and then we worked out what the diplomatic situation between the three elf cities was.
My favorite mapping software is a spreadsheet. It's easy to use and easy to share. I resize all of the cells so they are square, add a very light border to make a grid, type things in, add small pictograms or images, and print it off. During the game, changes are scribbled onto the map as the party alters the world. After a few game sessions, I update the file and reprint the map. Here's what it looked like well into the campaign (after many more locations and plot twists had been introduced by me and the players):
Cooperatively generating the map alongside character creation sets a good tone for the game. It gets the players invested in the shared storytelling. Ideally, they will have families they care about who live close to the action. And it tells them that the game will be about shaping and changing the world.
Persistent NPCs
In any game, it is very helpful to have the party be accompanied by at least one NPC on every mission. They can tell the character facts about the situation, as they see them, which allows for better role-playing and description. I recommend that the 'voice of God' never tell the PCs anything directly unless it is immediately visible to their senses or they pass an appropriate skill check.
These NPCs are especially important in this kind of game, because everything the party does has long-term consequences. Things that are obvious to you may not be obvious to the party, and having an NPC ally be the 'voice of reason' is a good way of nudging them away from doing things that seem stupid to you. But keep in character and be sure that they know that all NPCs are sometimes unreliable narrators with their own agendas.
A good setup is to have three three key NPCs of the party's level, each loyal to the civ but with different priorities and goals. Each of them is a source of missions, where they ask the party to go with them to accomplish a goal or respond to a crisis. But the party will not be able to do everything they all ask, so they have to prioritize.
Make a character sheet for them and keep them at party level. If necessary, design them to cover gaps in the party. Play them in combat, and design encounters for the larger party. If you have new players, use them to demonstrate basic combat tactics and options that the players may not be aware of.
New Systems
The three tricks above are the most important, and they might be all you need. If the party is staying in one collaboratively-created location, claiming and developing all the real estate it clears out, and working with NPCs who are sources of quests to improve the local area, then you have a civilization-building game.
Most groups just handle the effects of development narratively. This is fine, but it can help to add a bit of structure to explicitly model and reward certain player actions.
Civilization Saving Throws
To solidify the sense that the civilization is a real thing with an identity, rather than just a collection of places on the map, it should have its own saving throw modifiers. Whenever something threatens the civ, it gets a saving throw to resist, and the players only have to get involved if it fails. I'll present simple rules for managing and improving the civ's saves later, if you want them, but really, 80% of the value of this rule comes from doing literally anything at all to allow characters to affect the saves, and having the saves affect the plot.
There are many systems you could use to track and manage these saves. Atlantis: Second Age has a flavorful system of assigning six elemental attributes to locations, which the party can work to improve. But I use the 5e system of six attribute-based saves.
The Strength modifier represents the civilization’s military and law enforcement ability. Making a Str save means sending in troops. Anything that improves the training, equipment or leadership of soldiers, police, or militia increases the Strength modifier.
The Dexterity modifier represents the civilization's ability to quickly move people and resources from one place to another. Making a Dex save means sending in money or supplies. Good transportation networks, liquid markets, and anything that increases the disposable wealth of the civ will increase its Dexterity modifier.
The Constitution modifier represents the health and quality of life of people in the civilization. Making a Con save means the people toughing out a situation, doing a lot of physical labor in a hurry, or outsiders being won over by their quality of life. Anything that increases food security, medical care, or the social support systems increases the Constitution saving throw.
The Intelligence modifier represents the level of education of the civilization. It also represents the ability of the government's internal and external intelligence apparatus to discover plots. Making an Int save means devising a good plan or a clever solution to a problem.
The Wisdom modifier represents the piety, morality, and cooperativeness of the civilization. It also represents the church’s ability to respond to supernatural threats. Making a Wis save means people looking out for their neighbors and doing the right thing for the community.
The Charisma modifier represents how loyal the population and NPCs are to the party, the government, and/or the ideal of the civilization. It also represents the pride and energy and valor of the people and NPCs. Making Cha save means people deciding to be loyal, and/or reacting with bold energy to a threat.
Write the saving throw modifiers for every friendly civilization in a box on the map, under the civ’s name. Whenever something happens in-game to strengthen or weaken a civilization, adjust its saving throw modifiers. Always tell the party that you are doing this, and mark it down immediately, so they see the effects of their actions.
Adapting Modules
The easiest way to use this system is to make the civilization saving throws decide what module to run. Choose two different level-appropriate modules that you think would be fun: one about defending some civilized place being threatened, and another about going off on an adventure to explore a dungeon or wilderness area. Then, decide on a civilization saving throw for the defensive module, using one of the saves above. If the civ fails the save, use that module, but if it makes the save, use the adventure one. In either case, change the module so that one of the key NPCs introduces the situation and accompanies the party.
After they succeed on a defensive module, do some role-playing to increase some of the civilization's saving throws. After they succeed on an adventure module, do some role-playing to develop or rebuild the area and add it to the civ, and maybe lower one or two saving throws to represent the civ getting stretched thinner. If you want a bit more structure, supplement the role-playing with the systems I describe below.
Then repeat the process with two more modules appropriate to their new level, one defending a civilization and another clearing a new place.
In order to give an extra incentive to build up the civilization, and the resources to do it, try to choose adventure modules that give more rewards, or add an extra treasure hoard to the adventure module. It also helps to make the tone of the defensive modules more gritty and desperate, with a risk of NPC death, and make the tone of the adventuring modules more heroic.
Military Action
When players can influence a civilization, they can command military forces, and often they will want to use those forces to go and do something. You want to let them do this, but you want to run an RPG, not a wargame. The solution is to use military action as a method to generate interesting level-appropriate encounters.
Whenever there is a battle, do the following:
1) Split the enemy forces into roughly-equal-power fronts that would each be a Hard encounter for the party.
2) Have the civ roll a saving throw (usually Strength) for combat on each front.
2a) (optional, for larger and better-trained armies) Whenever the civ fails its first saving throw, it rolls a Charisma saving throw. If it succeeds, the unit retreats in good order and the front remains stable.
3) Wherever the civ fails one or both saving throws, the PCs, functioning as the tactical reserve, come to the rescue. Roughly 80% of the civ's forces on that front will be fleeing, 10% will be dead or wounded on the field, and 10% will be available to assist the party.
If the party wins all of its fights, their civ wins the battle.
This should usually generate 2-3 balanced encounters (without any rest) for a fun game session, although it may stretch to two sessions with a less-experienced gaming group. In addition to being a lot easier to run, it is more realistic than a typical strategy game. Before modern armies, battles, even large ones, were often decided by the timely actions of individuals.
For more details, see my post on Mass Combat.
Civilization Level and Effects
A civilization will attract predatory attacks with challenge rating up to its level (technically, a Medium to Hard encounter for a party of that level). Monsters or armies will be attracted by the increased wealth available to loot, and the characters must defend the civilization. In general, higher-level threats don't bother looting lower-level civilizations, because the return isn't worth the trouble.
A civilization will have NPCs with a level up to its own. These NPCs are not automatically loyal to the party, but with good role-playing and investment they might be recruited to assist with quests. In general, however, the NPCs spend their time pursuing their own goals and dealing with lower-level threats to the civilization.
These two rules produce a realistic way to supply the party with level-appropriate encounters, assuming that the civilization's level is about the same as the party's level, which will usually be the case if things are going well.
There are two choices for deciding the civ's level.
1) Handle it narratively and use it as a balancing mechanism. If things are going badly, the civilization is a few levels lower than the party, which makes things easier to deal with. Conversely, if the party achieves extraordinary success, the civilization will be a couple levels higher than they are, and they may be overextended.
2) The level of the civilization is equal to the number of fully developed sites it has on the map. Depending on the scale you choose, a site could be an entire province or nation, but I usually run smaller-scale games where a site is a town, mine, port, or farming region. To develop a location into a site, the party must first clear monsters or enemies out by adventuring there, and then work to develop it. At your discretion, you can also require some work or attention at existing sites to level up the civ.
If using the rules for hit dice activities below, the amount of work required to develop a site and integrate it into the civ is a number of successful projects equal to the civ's current level (some of which might take place at other sites).
Ideally, the players see leveling up the civilization as its own reward; making a high-level civ means victory in the game. But you can choose to give them other benefits. Here are a few suggestions:
Buying, Trading, and Selling Magic Items
The players can attempt to purchase magic items if (and only if) they are closely linked to a civilization. They choose the type of item they want, then roll a Persuasion or Investigation check, with a bonus equal to the civ's level. Add 1 to the DC for each level the party should be to purchase the item. If they succeed, they roll on the appropriate table, and may pay the item's cost to purchase it.
For example, using the D&D 5th edition DMG:
DC 15: Table A (50 gp)
DC 20: Table B, or permanent common items (100 gp)
DC 25: Table C or F (500 gp)
DC 30: Table D or G (5,000 gp)
DC 35: Table E or H (50,000 gp)
DC 40: Table I (500,000 gp)
The DC increases by 2 for each previous attempt, success or failure, to make any trade in the magic item market since the civilization last gained a level.
For every 5 points that the roll beats the DC, the number of items available to purchase is doubled.
For example, if a PC wants a permanent uncommon item, and beats a DC 25 (which usually requires a level 5+ civ even with a decent skill and roll) they can roll for an item on Table F, and pay 500 gp if they like it. If they beat a DC 30, they roll twice and may purchase either one for 500, or both for 1000.
It is usually best to give surplus items to aligned NPCs. However, if necessary, the same procedure can be used to trade or sell items. A PC can try to replace one item with a different random item of the same type by using the procedure above, and paying the item instead of money, or they can get 10x(d6+4)% of the item’s cash value.
Buying Mundane Items and Vehicles
The procedure to buy magic items can also be used to purchase expensive mundane items, like warhorses or plate armor or ships. Treat them as a magical item, and interpolate the DC (e.g. plate armor, at 1500 gp, would require DC 28)
Additionally or alternately, the civ’s sites can be used to restrict what items can be purchased. For example, metal items could require a mine or a port, perhaps in addition to the proper level.
Producing Magic Items
There are two different philosophies and rules systems for producing magic items. One says that production should be a unique and complicated affair, and another allows for mass production. I actually recommend using both.
Unique Item Quest
The same rules can be used for producing an item in a unique way, reassembling an ancient broken item, and questing for an item. If the party is closely connected to a civ, they can try to purchase a formula or map or clues for an item that can be obtained locally. Then, to get the item, the party goes on adventure, appropriate to their level, that gives no other treasure.
The difficulty and expense is one step on the table below purchasing the item directly. For example, meeting a DC 25 check allows the party to learn about an adventure that will result in a random item on Table G, and they can purchase the details (which could be a map, a required key, or the assistance of an NPC in crafting or reassembling it) for 500 gp.
Mass Producing Items
In D&D 5e, using DMG rules, most of the difficulty of producing a magic item comes from finding the formula. Once you have that, it is relatively easy to make more. Some people may disagree, but I like leaning into this and making it a feature of the world. The PCs should be allowed and encouraged to set up a site that manufactures items for use and export. Civilizations can be known as the place that makes a particular item.
If the party is connected to a civ, the party can attempt to develop and/or commission a formula for an item that can be mass-produced with local materials. The item will be random, and developing the formula for is one step on the table above the item. For example, a formula for a random Table A item requires a DC 20 and costs 100 gp. Once they have the formula, they can set up a site and staff it with NPCs to produce the item. This does not necessarily require spellcasters, anyone with appropriate tool proficiencies and a thematic connection to the item should work.
Once the site is up and running, its output will scale with the civilization. The scaling should be roughly exponential rather than linear. In general, the site should start by producing one permanent item, or four temporary items, per year. The first few times the civ levels up, the output is doubled, and after that, it increases by a smaller percent. For example, a level 7 civ with a new site for making +1 halberds will produce one every year, but a level 17 civ should produce hundreds.
Much of the early output will likely be prototypes, or go to NPCs who helped provide the skills or raw materials or capital to make the production site happen. But once the site is regularly producing, the PCs can regularly buy the items at the listed price, or make a skill check to buy the items at half the listed price.
Other Downtime Activities
Most downtime activities can be gated by the civ’s level and/or the sites it has on the map. For example, Carousing may not be possible unless the civilization is at least level 5, or has a proper urban location.
Rules Changes
Aside from the civilization level rules and item purchasing, everything I've discussed so far can apply to any game system, but a few of my recommended rules changes are specific to the modern-rules D&D family of games (3rd+ and Pathfinder). If you are using another system, you probably want to make similar adjustments.
Yearly Long Rests
One of the biggest problems in the flow of the game is that the party has an incentive to take a long rest after each encounter. Good GMs constantly have to fight this to preserve game balance, by inventing reasons why resting is impossible. One very good tool is to switch to the Gritty Realism rest variant, but you can go a lot farther.
I recommend changing the rules so that an 'adventuring day' becomes an adventuring year. A long rest takes 3 months, and characters can benefit from no more than one per year. A short rest takes one month. Any magic items or class abilities that refresh per day now refresh once per year.
Aside from the narrative and flavor, this changes very little about the flow of the game. There will usually be some role-playing and a couple of combat encounters between each short rest. You might have to adapt published adventures that are designed around rest periods, by making the events stretch over longer times, but most shorter modules are unaffected.
This rest variant encourages a grand and epic scale of role-playing. It might take 50 years of game time to get to level 20, even if the party is handling as many encounters as they can every year. It forces hard choices, because the characters will not be able to handle every threat. It allows for more depth of strategy, like using intrigues and plots and feints to burn through spell slots of an enemy spellcaster and then attacking before they can long rest (and the PCs should be paranoid that someone is trying to do this to them).
Hit Dice Activities
Any game system that allows people to do things outside of adventures needs rules for determining how many things the PCs can do, and how successful they are likely to be. This system is one I've used successfully for years. The flavor is that hit dice represent a pool of energy, vigor, focus, knowledge, and connections that can be used to accomplish many things, not just healing. Whenever a player wants to undertake a major project, they must spend a hit die to roll a skill check.
To support this, there are two rules changes:
1) A long rest restores half of the characters' hit points, but all of their hit dice.
2) A player's lifestyle proves a bonus to hit dice recovery: +1 for Comfortable, +2 for Wealthy, +3 for Aristocratic. This can allow them to have more hit dice than their level.
If you introduce a situation, or if it develops naturally, it is usually not appropriate to require spending hit dice. Just roll the checks as normal. Spending a hit die should be something that the player chooses to do, to affect the world, over a period of weeks or months. Some examples of projects that require a hit die are:
Discovering an important piece of information (trying to find who committed a crime, searching a ruin for clues, etc.)
Teaching skills to the population
Training the army or militia
Recruiting an NPC ally
Purchasing a magic item
Negotiating a peace treaty with a neighboring civ or creature
Learning a new language or tool proficiency
Resolving a dispute between factions in the civ
Helping with the harvest to ensure a good food supply
Supervising a construction project
Turning a dungeon or ruin into a new fortress or settlement will require several of these construction projects. After the party clears out a new space, ask them what they want to do with it, and give them an estimate of how many successful hit-die checks it will take to accomplish that task.
Most XGE downtime activities should also use up a hit die, but increase the scale, so it represents about a month of work rather than a week.
This system forces interesting choices, and has two mechanical advantages. First, it makes combat interesting even if there is little or no risk of defeat. The party always has an incentive to win as efficiently as possible, to preserve their capacity for downtime action. And second, it makes leveling up matter in a game that is mostly about skill use and role-playing, with relatively few combat encounters.
Earning Money and Lifestyle Costs
In order to practice a profession and earn money, characters spend a hit die and roll a skill or tool check. They get the check result times 50 gp. Or they can play it safe and take a 7 on the die roll, simply spending a hit die to guarantee a minimal income.
Optional rules: Each character can earn money a number of times per year equal to half the civ’s level, rounded up. In general, civs below level 5 can only support one roll for each skilled profession, so there could be trouble if another PC or key NPC wants to practice the same profession. If they cannot negotiate and both attempt to practice, then whoever rolls lower gets somewhere between nothing and half the roll.
A Modest lifestyle costs 350 gp a year, Comfortable costs 700, Wealthy costs 1400, and Aristocratic costs 3,500. For simplicity, pay these costs at the beginning of each long rest, and apply the relevant hit die bonuses.
Most PHB background features will provide either free lifestyle support or advantage on the profession skill check, as long as the character acts appropriately. (It might be hard to use Folk Hero Rustic Hospitality to get a free Modest lifestyle if you have been acting like a tyrant). Any feature that does not give a feat or a regular gameplay benefit should benefit the character in this way. If a feature provides a free modest lifestyle, then all others cost 350 less.
If a character is unable to afford a Modest lifestyle and has no appropriate background feature, then the civilization will provide it, although this will cause a reduction in a save modifier. (A desperate leader is an ill omen and will cause doubts.)
1st-level characters with no external means of support must use their only hit die to support themselves, unless they looted enough money in their adventuring year. This can create a sense of scarcity and desperation, which they eventually grow out of. This is often appropriate for skilled players, but for new players, you usually want to be nicer. I recommend giving them a free Comfortable or Wealthy lifestyle from some source, so they are not desperate, and they have two or three hit dice to spend on healing and civilization-boosting projects.
Crafting
Crafting uses the same rules as earning money: Spend a hit die and roll a tool check, and add value to the project equal to the check result times 50 gp. Usually this means turning 50 gp of materials into 100 gp of finished goods. If players were spending a hit die to earn a living in a related profession, then higher rolls can turn into crafted items. For example, a player working as a blacksmith who rolls a 19 can get a Comfortable lifestyle from the first 14, and then turn 250 gp of metal into 500 gp of items.
If the civilization has a formula for a magic item, and a working site devoted to that item, a character with spellcasting, an appropriate tool proficiency, and/or thematic connection to the item can craft the magic item in this way. This increases the civ’s base rate of production rather than replacing it.
Capital Improvements
I do not use complicated rules for how to manage a civilization. I'm not trying to make a tabletop equivalent of a grand strategy game like Crusader Kings. Usually we just narratively handle the growth of civilizations and the character's interactions with them. However, good role-playing often comes from forcing discussions and hard choices about how to spend limited resources.
So here's a simple system that links uses an abstracted resource called Capital. Capital includes physical objects like trade goods, specie, tools, and weapons, but also social capital like the population's skills, loyalty, cultural pride, and cohesiveness. You can make the Capital tracking as simple or as complicated as your group wants. You can have it all be a big lump, or just separate physical and social capital, or be specific about what was earned after each mission.
A core loop of a civilization-building RPG is the party claims locations, and acquires Capital, and uses the Capital to fix up the locations and improve their civ. This should be handled abstractly, in a freeform storytelling kind of way. Most parties will have lots of ideas for what they want to do. The main function of Capital as a resource is to force them to make choices. There should always be more locations to develop than Capital on hand, so they have to choose which locations they care about most.
Spending a unit of Capital replaces a successful Hit Die Activity. A project that would normally require a hit die and skill check can be accomplished with Capital instead. If you are tracking different types, you can require that an appropriate type be used for a project, or count it as two successes if you think the party used it in a clever or appropriate way.
At the end of some missions, the party obtains Capital. If you want this to be roughly balanced with the standard rate of treasure accumulation, then the Capital replaces the money, gems, and art objects in treasure hoards; and the party should get about one unit of Capital per level per year. Magic item rolls from the hoard can be given at the same time, but it is often better to give them out in different missions. A good 'adventuring year' is to have one session where the party goes out to clear a new location and hopefully get magic-item loot, and two sessions where they are handling threats and earning Capital (by looting the invaders and/or generating trust and loyalty in the population)
In addition to boosting the civ like a Hit Die success, one unit of Capital can also be used to produce 500 gp of specie and/or trade goods, or give two players a Modest lifestyle, or give one player a Comfortable lifestyle, or upgrade a Comfortable lifestyle to Wealthy.
Capital can also be used to provide estates for the players. Two units of capital is enough to set up an estate that gives a Modest income each year, and four is a Comfortable lifestyle. This does not mean that they are earning an interest rate of 25% a year, it means that they have an efficient setup with trusted servants, so they're no longer paying hotel and restaurant prices for their lifestyle.
Increasing Civ Save Modifiers
At your discretion, Capital (and Hit Die activities) can be used to increase the civilization's saving throw modifiers. If the type of capital is appropriate, the cost is two times the new modifier (minimum 2). For less appropriate forms of capital, it could be three or four times the new modifier.
If you do not use this rule, be sure to sometimes increase the modifiers based on the plot and the PC actions.
Play example: A level 5 party just led the army in a victory against a horde of thousands of zombies. The army did most of the work, but the party intervened in a few places where the battle was going badly. They are hailed as saviors, earning 3 units of social Capital. The civ's Charisma saving throw is +1, and the party would like to boost it. The GM decides that this is an appropriate use of the Capital. It will cost 4 Capital to raise it to +2, so a player decides to spend a Hit Die to add the 4th. Given the situation, the GM calls for a DC 10 Persuasion check, and the character easily passes. The civ's saving throw is increased, and the change is marked.
Recommended Game Flow
A good flow for the game sessions is to start with the PC's going on a mission that they chose and planned last session, or handling a crisis or cliffhanger that was revealed last session. Do what you can to wrap that up when there is about an hour left in the session. Then, they return to their home base, take a short rest, and roll several civ saving throws against new events. Events can be chosen at random on the table below, or they can be based on what just happened in that game session, or they could be a 'slow burn' plot development from previous events. I recommend one of each.
After the rolls, the party holds a planning discussion. Different key NPCs will present their opinions and lobby for different actions. The party can role-play and make skill checks to learn more and decide what to do. Ideally, this ends the session. Before the next session, plan and create the session and encounters for the event that the party chose to intervene in, possibly by finding and adapting a module. Usually this is a straightforward combat mission or role-playing, but it could also involve investigation or going on a quest to find a special item.
After three such sessions (usually spring, summer, and autumn) there is winter, and a long rest, and the next session will be spring of the next year.
Rolling for Events
One at a time, announce the event, and have a player roll the initial save. After the save, read the result. Encourage the player to tell a more detailed story about what happened. If the event causes the PCs to roll saving throws on a failure, or otherwise does not have a secondary Civ saving throw, handle it immediately.
After all initial saves are rolled, the party chooses whether to follow up on successes. All success rolls require spending a hit die to attempt. Then, if there were any failures, the party chooses whether and where to intervene. If failure would cause a site to be lost, decide which site is at risk, and tell the party now. At your discretion, if there are two failures at the same site, the party can try to handle both of them, but they will not get a short rest between the two missions.
All events and encounters are the level of the civilization unless otherwise noted. If the party fails or retreats from its mission, failure is automatic; there is no secondary saving throw.
After the party returns from whatever mission it chose, they learn what happened in other failures. Roll the secondary saves. If the site is lost, it is replaced with either the civ's undeveloped property or an enemy location. This could be a ruin, or an active enemy site. It can be attacked and or reclaimed later. If every major population center in the civ (usually towns and cities) is lost, the civilization collapses into ruin and chaos. (This should not mean the end of the campaign. The PCs can continue to adventure in the ruins, salvaging what and who they can. If you have plans for the story to continue after civ failure, then the players will know that failure is a real possibility. For real tension, try to set things up so that there is a 25% chance of civ failure even if the players do their job well, and tell them that you are doing this.)
In the early game, I recommend just two or three rolls for the entire civilization. As the civilization grows to more sites, and accumulates competent NPCs and increases its saving throws, and as the players become more comfortable with the system, make more rolls. For a forgiving game, low-level civs start with save modifiers of 0, with one or two at +1. For more gritty games, start with modifiers between -3 and +1.
Events Table
If rolling randomly on the entire table, roll d100 and add the civ's level. If rolling randomly within a type, roll d10 and treat the 0 as a 0.
0s. Environmental Events
Intervening requires a number of successful hit-dice skill checks equal to the civ's level. It is rare that these problems can be solved by fighting things, but at your discretion, the party might do a task for a deity or larger organization capable of assisting.
0. Grazing lands are barren. Wisdom DC 10.
Success. People find new pasture in your civ. No effect.
Failure: Herders move into neighboring lands, triggering conflict. Strength DC 15 or roll two Invasion Events.
1. Crop yields are lower. Dexterity DC 10.
Success: Food is delivered. No effect.
Failure: Lean times. Constitution DC 10 or an NPC is lost (either they ran away or starved).
2. Grazing lands are barren. Wisdom DC 10.
Success. People find new pasture in your civ. No effect.
Failure. Herds must be culled. Intelligence DC 10 or -1 Strength
3. Crop yields are lower. Dexterity DC 10.
Success: Food is delivered. No effect.
Failure: Widespread theft and riots. Strength DC 10 or -1 Dexterity
4. Grazing lands are barren. Wisdom DC 10.
Success. People find new pasture in your civ. No effect.
Failure. People consider abandoning the area. Dexterity DC 10 or site is lost.
5. Crop yields are lower. Dexterity DC 10.
Success: Food is delivered. No effect.
Failure: Refugees. Wisdom DC 10 or -1 Charisma.
6. Lack of timber. Intelligence DC 10.
Success: Replacements are found. No effect.
Failure: Constitution DC 15 or -1 Dexterity.
7. Crop yields are lower. Dexterity DC 10.
Success: Food is delivered. No effect.
Failure: Murmurs of rebellion. Charisma DC 10 or site is lost.
8. Crop yields are lower. Dexterity DC 10.
Success: Food is delivered. No effect.
Failure: Plague. Wisdom DC 10 or roll three Disease Events.
9. Foul weather. Dexterity DC 10.
Success: No effect.
Failure: Travel is hindered. If the PCs go anywhere this season other than adjacent sites, they must make a DC 10 Constitution save or lose a hit die or take a level of exhaustion.
10s. Disease Events
Party intervention in failure might involve going on a quest to find rare healing items, or to petition the assistance of gods or another organization, or in some cases, to track down the disease vector.
10. Dysentery. Constitution DC 12.
Success: No effect.
Failure: Constitution DC 15 or an NPC dies.
11. Barracks fever. Constitution DC 10.
Success: No effect.
Constitution DC 15 or -1 Strength.
12-14. Disease spreads everywhere. Constitution DC 10.
Success: No effect.
Failure: All PCs immediately make a DC 12 Constitution save or suffer one level of exhaustion.
15-17. Evervation. Constitution DC 10.
Success: No effect.
Failure: All PCs immediately make a DC 12 Constitution save or lose hit dice equal to one third of their maximum, rounded up.
18. An outbreak of ague. Constitution DC 10
Success: No effect.
Failure: Intelligence DC 15 or -1 Con.
19. A key NPC is infected with lycanthropy. Constitution DC 12.
Success: They are partly cured and remain in control, and gain a shifter racial ability.
Failure: Charisma DC 15 or they become a monstrous adversary.
20s. Political events
Intervention in failure is role-playing, investigating, and possibly attacking ringleaders or mobs.
20. A key NPC has low morale. Charisma DC 10.
Success: No effect.
Failure: Dexterity DC 15 or lose the NPC.
21. A group of religious fundamentalists claims that society is corrupt. Charisma DC 10.
Success: They send you a plan to improve society. DC 10 religion for 2 Capital.
Failure: They riot and threaten to rebel. Strength DC 15 or site is lost.
22. A new tavern opens. Intelligence DC 10.
Success: DC 15 Performance for 2 Capital.
Failure: An NPC develops an addiction. Wisdom DC 15 or they spiral into insanity.
23. Foreign criminals arrive. Charisma DC 10.
Success: Local 'power brokers' make them an offer they can't refuse. No effect.
Failure: Local criminals join them. Intelligence DC 15 or Wisdom -1.
24. Diplomatic dispute with neighbor. Charisma DC 10.
Success: Dispute is resolved.
Failure: They demand tribute. Dexterity DC 15 or roll two Invasion Events.
25. An honest cop has been poisoned. Intelligence DC 12.
Success: NPC investigators find the perpetrator and antidote.
Failure: Constitution DC 12 or NPC dies.
26. Police corruption. Wisdom DC 8 + Strength mod.
Success: Clerics succeed in anti-corruption reforms.
Failure: Charisma DC 15 or -1 Wisdom.
27. Succession crisis. Charisma DC 10.
Success: A change of government or personnel that has no direct effect on the party's operations.
Failure: Wisdom DC 15, or a key NPC is exiled (or killed), and replaced with a different NPC three levels lower.
28-29. Neighbor requests help. Constitution DC 12.
Success: NPCs can handle it.
Failure: Send lawyers, PCs, or money. Intelligence DC 15, Dexterity DC 15, or -1 Wisdom and the neighboring civ loses a site or is destroyed.
30s and 40s. Military events
Party intervention in failure is leading a military response. Roll seven DC 10 Strength checks, and every failure is a level-appropriate encounter against a mass of troops led by an officer.
30-31. Portal to another plane opens. Add a portal location to the map. Wisdom DC 10.
Success: Local priests seal the portal - for now.
Failure: Hordes of demons or extraplanar creatures. Wisdom DC 12 and Charisma DC 12 or site is lost.
32. Great Modron March. Intelligence DC 10.
Success: People work around them. No effect.
Failure: Conflict. Strength DC 10 and Constitution DC 15 or site is lost.
33. A horde of undead. Constitution DC 12.
Success: People build traps and barricades and hold out until the undead collapse.
Failure: Strength DC 10, Wisdom DC 10, and Charisma DC 10 or site is lost.
34. A horde of undead. Strength DC 12.
Success: The militia handles it.
Failure: Strength DC 10, Wisdom DC 10, and Charisma DC 10 or site is lost.
35. The plants come alive. Wisdom DC 10.
Success: Druids negotiate a peace. Nature DC 10 for two Capital.
Failure: They attack. Strength DC 15 and Charisma DC 10 or site is lost.
36. Workers are disgruntled. Charisma DC 12.
Success: Local officials talk things out and restore the peace.
Failure: Riots and Rebellion. Strength DC 15 or site is lost.
37. Low morale in border troops. Charisma DC 10 + Strength mod.
Success: Local officials talk things out.
Failure: Troops demand more pay and threaten rebellion. Dexterity DC 15 or site is lost.
38. A warlord emerges. Add location to map. Strength DC 12.
Success: The local garrison bottles them up - for now.
Failure: They defeat the militia and demand tribute. Dexterity DC 15 or roll two Invasion Events.
39. Nomad cavalry. Dexterity DC 10 and Strength DC 10.
Success: They are driven off.
Failure: They defeat the militia and demand tribute. Dexterity DC 15 or roll two Invasion Events.
40s. Invasion Events
This subset of military events represents enemy states conducting an organized and determined invasion. When rolling a random d100 event, ignore all Invasion Events if the borders are well-scouted, there are good diplomatic relations with all neighbors, and there are no unclaimed planar portal locations near your civ. Whenever a site is lost due to one of these events, roll another Invasion Event next short rest until the enemy is defeated or a peace is negotiated.
40-44. Army marches across your borders. Strength DC 15.
Success: Local commanders force them to retreat. No effect.
Failure: Strength DC 12 and Charisma DC 10 or site is lost.
45. Army marches across your borders. Charisma DC 15.
Success: Partisans disrupt their supplies and force them to retreat. No effect.
Failure: Strength DC 12 and Charisma DC 10 or site is lost.
46. Army marches across your borders. Dexterity DC 15.
Success: Their commander is bribed to fake logistical difficulties. No effect.
Failure: Strength DC 12 and Charisma DC 10 or site is lost.
47. Army marches across your borders. Intelligence DC 15.
Success: Your agents assassinate their commander, and the army retreats in confusion. No effect.
Failure: Strength DC 12 and Charisma DC 10 or site is lost.
48. The enemy tries to raise a fifth column. Charisma DC 10.
Success: No effect.
Failure: Your civ immediately gets -2 Strength, which can be restored if the PCs succeed in negotiating with or assassinating the right people. Strength DC 15 or roll two Invasion Events.
49. Enemies approach a partially fortified choke point. Add site to map. Constitution DC 15
Success: The fortification is completed and they are held off.
Failure: Strength DC 13 or -1 Strength and site is lost.
50s. Monster Events
Intervention is usually fighting things.
50-52. The ground stirs; something is burrowing. Add lair location to map. Constitution DC 10.
Success: Locals seal and fence it in - for now.
Failure: Monsters emerge and terrorize the countryside. Strength DC 10 and Charisma DC 10 or site is lost.
53. A preteen has powerful innate magic. Wisdom DC 10.
Success: DC 15 persuasion for a new NPC.
Failure: People start dying. Charisma DC 12 or -1 Dexterity.
54. People report that their loved ones have been replaced by imposters. Wisdom DC 10.
Success: Invasion is stopped early.
Failure: Strength DC 10 and Intelligence DC 10 or site is lost and roll an Invasion Event.
55. A glowing meteorite falls from the sky. Intelligence DC 10.
Success: Materials are harvested. Arcana DC 10 for 2 Capital.
Failure. Local wildlife mutates. Strength DC 12 or site is lost.
56. Giant ants. Constitution DC 12.
Success: They are contained in pens and can be fed and trained. Animal Handling DC 10 for 2 capital.
Failure. Strength DC 10 and Wisdom DC 10 or site is lost.
57-59. A portal to another plane opens. Add a portal location to the map. Wisdom DC 10.
Success: Local priests seal the portal - for now.
Failure: Demons or extraplanar creatures emerge and terrorize the countryside. Strength DC 10 and Charisma DC 10 or site is lost.
60s. City Events
When rolling a random d100 event, ignore these events if the civilization has no large population centers.
60. Angels (civ level +3) appear to cast judgment. Wisdom DC 7.
Success: No effect.
Failure: Intelligence DC 15 and Charisma DC 15 or site is lost.
61. People talk politics in salons. Wisdom DC 10.
Success: Ideas for social improvement. History DC 10 for two Capital.
Failure: Revolution foments. Charisma DC 15 or roll three Political Events.
62. Homeowners install traps in their houses. Intelligence DC 10.
Success: History DC 10 for two Capital.
Failure: A beloved child has been killed by a neighbor's trap. Risk of riots. Wisdom DC 15 or -1 Charisma.
63. Scholars study ancient tomes. Wisdom DC 10.
Success: History DC 10 for two Capital.
Failure: They are compelled by evil magic. Strength DC 10 and Intelligence DC 10 or a new adversary NPC is created that causes an event every short rest for the next year.
64. Arcane college opens. Add location. Intelligence DC 10.
Success: They consider integrating into society. Persuasion DC 15 to gain new arcane-caster NPC. An arcane-caster PC or allied NPC can make a DC 15 Arcana check to make the location the civ's property.
Failure: Their loyalties are elsewhere, and they attract many of your smartest people. Dexterity DC 15, or -2 Intelligence until they are integrated.
65. Sewers overflow. Dexterity DC 10.
Success: Repairs are made.
Failure: Constitution DC 15 or roll three Disease Events.
66. A magician lures all of the vermin away. Wisdom DC 8.
Success: Nature DC 10 for 2 capital. Persuasion DC 15 for a new NPC Ally.
Failure: The city tries to cheat them out of payment, and they lure away all the children. Dexterity DC 15 or -2 Wisdom.
67. Cathedral opens. Add location to map. Wisdom DC 10.
Success: They consider integrating into society. Persuasion DC 15 to gain new divine-caster NPC. A divine-caster PC or allied NPC can make a DC 15 Religion check to make the location the civ's property.
Failure: They denounce your sinful civilization, and call down the wrath of the gods. Strength DC 15 or roll a Monster Event every short rest until they are defeated or negotiated with.
68. Thieves guild opens. Intelligence DC 12.
Success: Pragmatists in your government reach an arrangement. Persuasion DC 15 to gain new NPC.
Failure: Someone needs to hunt them down before they rob everyone. Strength DC 15 or -2 Dex.
69. Houses of ill repute. Wisdom DC 10.
Success: Proper precautions are taken. No effect.
Failure: Intelligence DC 15 or roll three Disease Events.
70s. Mine Events
When rolling a random d100 event, ignore these events if the civilization has no mine sites.
70. Rust monsters. Charisma DC 10.
Success: Druids handle them. No effect.
Failure: Strength DC 10 and Intelligence DC 10 or site is lost.
71. Delving greedily and deeply. Wisdom DC 7.
Success: A rich vein. 1 Capital. Persuasion DC 12 or repeat this event next short rest at +1 DC.
Failure: Demon is unearthed (civ level +3). Strength DC 15 and Charisma DC 15 or site is lost.
72. Delving timidly and shallowly. Intelligence DC 10.
Success: No effect.
Failure: Low productivity. The mine is unprofitable and may be abandoned. Wisdom DC 12 or site is lost.
73. An influx of gold. Dexterity DC 10.
Success: Goods are imported. History DC 10 for two Capital.
Failure: Inflation and economic disruption. Intelligence DC 10 or -1 Wisdom.
74. Connecting to the Underdark. Add location to map. Intelligence DC 10.
Success: The tunnels are sealed and guarded - for now.
Failure: Monsters are unleashed. Strength DC 10 and Charisma DC 15 or site is lost.
75. Dwarf refugees are hired as workers. Wisdom DC 10.
Success: Higher productivity. History DC 10 for 2 Capital.
Failure: They feel underpaid and disrespected, leading to tension. Charisma DC 12 and Dexterity DC 12 or -1 Wisdom.
76. Weapons-grade adamantium is discovered. Wisdom DC 10.
Success. Arcana DC 10 for two Capital.
Failure. Your neighbors feel threatened and require diplomatic assurances. Dexterity DC 15 or roll two Invasion Events.
77-79. Monsters in the mines. Constitution DC 12.
Success: Miners collapse tunnels on them.
Failure. Strength DC 12 and Charisma DC 12 or site is lost.
80s. Port Events
When rolling a random d100 event, ignore these events if the civilization has no port sites. This is a seaport in a normal game and a spaceport in a Spelljammer game.
80. Great white whale. Constitution DC 10.
Success: Chef's tools DC 10 for 2 Capital.
Failure: An NPC becomes obsessed. Charisma DC 15 or they disappear.
81. Ships arrive from a foreign power. Wisdom DC 10.
Success: Peaceful trade. History DC 10 for 2 Capital.
Failure: Hostile encounters. Strength DC 15 or or roll two Invasion Events.
82. Tales of a ghost ship. Add location to map. Wisdom DC 10.
Success: Priests hold it off - for now.
Failure: Ships start disappearing. Intelligence DC 10 and Charisma DC 10 or -2 Dexterity as long as the location is on the map.
83. A new civilization is discovered. Add location to map. Intelligence DC 10.
Success: Anthropologists make peaceful contact. Persuasion DC 10 for 2 capital.
Failure: Hostile encounters. Strength DC 15 or or roll three Port Events.
84. New island appears. Add location to map. Charisma DC 10.
Success: Citizens explore and colonize. Persuasion DC 15 to make it the civ's property, which can be developed into a rural site.
Failure: It becomes a den of thieves and pirates. Strength DC 15 or -2 Wisdom as long as the location is unclaimed.
85-86. Pirates attack shipping. Strength DC 10 and Dexterity DC 10.
Success: Your navy handles them. No effect.
Failure: They rule the waves and threaten the port. Intelligence DC 15 or site is lost.
87-89. Monster. Strength DC 10 and Charisma DC 10.
Success: Harbor patrol handles it. No effect.
Failure: Constitution DC 15 or site is lost.
90s. Rural events
When rolling a random d100 event, ignore these events if the civilization has no rural sites. This is rare, but possible. A rural site is a region on the map that mainly provides food and raw materials.
90. Young adventurers find the location of an ancient site of power. Intelligence DC 10.
Success: The party may buy the map by spending 25xlevel gp.
Failure: A monster is released. Intelligence DC 15 or site is lost.
91. Aerie discovered. Add location to map. Wisdom DC 12.
Success: Peaceful contact. Diplomacy DC 15 to make flying mounts available for hire.
Failure: Flying monsters antagonized. Strength DC 15 and Constitution DC 10 or -1 Dexterity
92. Elf settlers buy land for orchards. Wisdom DC 10
Success: Higher productivity. Nature DC 10 for 2 capital.
Failure: They are isolated, leading to tension. Add location to map. Charisma DC 12 and Constitution DC 12, or -1 Wisdom until they are integrated.
93. Contact with barbarian tribe. Constitution DC 10
Success: Attracted by your lifestyle, they integrate into society. Persuasion DC 15 to gain new NPC.
Failure: They demand tribute. Add location to map. Dexterity DC 15 or roll two Invasion Events.
94. Contact with druid enclave. Add location to map. Wisdom DC 10
Success: They consider integrating into society. Persuasion DC 15 to gain new primal-caster NPC. A primal-caster PC or allied NPC can make a DC 15 Nature check to make the location the civ's property.
Failure: They denounce your destructive civilization. Charisma DC 15 or roll an Environmental Event every short rest until they are defeated or negotiated with.
95. Martial training center opens. Add location to map. Constitution DC 10
Success: They consider integrating into society. Persuasion DC 15 to gain new non-caster NPC. A non-caster PC or allied NPC can make a DC 15 History check to make the location the civ's property.
Failure: They withdraw from civilization, and attract many of your strongest people. Charisma DC 15, or -2 Strength until they are integrated.
96. Farm Animals Mutate. Intelligence DC 10.
Success: Wizards cure them.
Failure: Strength DC 15 or site is lost.
97-98. A forest becomes dark and haunted. Add location to map. Wisdom DC 10.
Success: Local druids contain the monsters - for now.
Failure: Monsters ravage farmland. Strength DC 15, or -2 Constitution while location remains.
99. Prospectors open a new mine. Add location to map. Charisma DC 10.
Success: The location is the civ's property, and can be developed into a site.
Failure: Emboldened by their wealth and a defensible position, they threaten to declare independence. Strength DC 15, Dexterity DC 15, or -2 Wisdom as long as they are independent.
100s+. Development events.
Wealth and progress brings new problems.
100. Land rush. Add a rural property to the map. Intelligence DC 15.
Success: Property rights are managed and expansion is controlled. The property can be developed into a rural site.
Failure: Settlers rush in heedlessly. Wisdom DC 15 or roll three Rural Events, each with +3 to the DC.
101. Alchemical experiments. Wisdom DC 10.
Success: History DC 10 for two Capital.
Failure: Pollution from an alchemy lab has mutated rats into monsters. Strength DC 10 and Charisma DC 10, or -1 Constitution.
102. Boom town. Wisdom DC 10.
Success: Civic projects. History DC 15 for two Capital.
Failure: Vice and corruption. Intelligence DC 15 or -1 Wisdom.
103. A World-Shaking Event (DMG pg. 27, or here) occurs. Roll randomly, or decide. Encourage all players to tell a story about how it ties into their characters' backgrounds and lives.
104. A middleman minority group arrives to trade. Wisdom DC 12.
Success: They are accepted into society. Persuasion DC 15 for an NPC of an exotic species. History DC 15 for two Capital.
Failure: They face discrimination and local officials propose confining them to a ghetto. Dexterity DC 15, or add location to map, and -1 Wisdom and roll a Political Event each short rest until they are integrated.
105. Neighbors become jealous. Charisma DC 12.
Success: Diplomats smooth it over.
Failure: Expensive concessions, or personal assurances from the party, are required to prevent war. Dexterity DC 17 or roll two Invasion Events.
106. A dragon arrives and demands tribute. Dexterity DC 12.
Success: It is paid off at a relatively low cost. Place a dragon lair on the map. -1 Dexterity, which is restored if the dragon is defeated.
Failure: It attacks. Strength DC 15 and Charisma DC 15, or site is lost.
107. An alchemist creates mechanical life. Intelligence DC 12.
Success: Autognome servitors. History DC 10 for 2 Capital.
Failure: Rampaging autognomes. Strength DC 12 or site is lost.
108. A sorcerer is attempting to summon spirits to do labor. Wisdom DC 12.
Success: Spirit servitors. Arcana DC 10 for 2 Capital.
Failure: Vengeful spirits. Charisma DC 12 or site is lost.
109. Magic item thieves. Intelligence DC 15.
Success: The ring is busted. Investigate DC 15 for a random uncommon item.
Failure: Each PC makes a DC 15 Intelligence saving throw or loses a permanent magic item at random. If they go on a mission immediately, the items can be recovered, but the items will be gone forever if the PCs delay.
110. A keystone species has been driven to local extinction. Intelligence DC 10.
Success: Druids readjust the ecosystem.
Failure: Someone needs to capture a replacement and reintroduce it. Strength DC 10 and Charisma DC 15 or roll three Environmental Events.
111-114. Development strains resources. Dex DC 10 + non-rural sites - ( 3 * rural sites).
Success: No effect.
Failure: Int DC 15 + non-rural sites - ( 3 * rural sites), or roll three Environmental Events, each with +5 to the DC.
115. Merchants create a permanent teleportation circle. Intelligence DC 12.
Success: Party spellcasters get the sigil sequence.
Failure: Enemies come through. Strength DC 15 or site is lost.
116+. Diseases of affluence. Constitution DC 10 + Dexterity mod.
Success: No effect.
Failure: Intelligence DC 15 or -1 Strength and -1 Dexterity.
Event Options
As you and your players gain experience with the civ events rolls, you can introduce these gradually, as appropriate:
Be creative with the interaction between map sites and events. Add bonuses for special sites the players build. If they want to do a project to protect against a certain type of event, let them. For example, if they build a fortress, give advantage on all military events near that fortress, and if they set up a druid’s sacred grove or wizard’s college, give advantage on environmental events. These special sites may or may not increase the civilization’s level, depending on how populated and integrated they are.
If a loyal NPC with appropriate skills and power is stationed at the affected location, make the initial saving throw with advantage. If a PC is at that location and has an appropriate skill, the player may spend a hit die to have the civ roll with advantage.
If the party has NPC allies in their headquarters, they can send them to help handle event failures. Convincing the NPC may require role-playing, and/or spending one or more hit dice and succeeding on a skill check. If an NPC with appropriate skills is dispatched to a failure, these saves have advantage.
A critical success is a natural 20, or a roll that beats the DC plus 10. It replaces the Success outcome with something you or the players deem appropriate. For example, a critical success on a monster attack might mean that a local makes friends with the monster or captures it alive, and the party can negotiate with it to become an active ally of the civilization.
A critical failure is a natural 1, or a roll that fails to meet the DC minus 10. It results in the failure event happening and being rolled immediately, with no chance for party intervention.
A critical failure on a secondary failure roll reduces its saving throw by one.
Many events will put an enemy location on the map. Each active enemy location that is in range of one of your civ's sites should roll an extra event about once per year. The party can go on a quest to an enemy site, or they can dispatch NPCs to deal with it. The roll required for an NPC to clear the site is the same as the roll that would be required if the initial event failed, but there is no consequence for failure unless the roll failed by 10 or more.
Splitting the Party
Sometimes, there will be two event failures, and the PCs will disagree on where to go. Or some PCs might care more about pursuing a different opportunity. If they are very focused on role-playing, their characters might insist on doing different things based on their strong personal beliefs.
If only one PC does something different, then that player should play an NPC ally or minion, possibly one that is a couple levels lower than the party, on the party’s main quest. Then their PC’s actions on the other event can be handled privately between sessions. If they were going to an event failure, they roll the secondary save with advantage.
If more than one PC wants to go on each option, then you can run two different game sessions. Each player will control their PC in one session, and an NPC or alternate character in the other. Alternately, the players could decide that it would not be fun to handle a certain mission in-game, even if their characters insist on handling it personally. In that case, you can have them roll a few hit-dice skill checks to determine mission success.
If the players are focused on recruiting and developing allies, they might assemble a ‘B team’ of alternates that they control. This can provide fun variety during a long campaign, especially if this group has a different alignment and goals. If the group decides that the main party’s quest would not be a fun session, they can control the B team instead.
Play Balance Notes
The only play-balance change in this system is that healing potions are much stronger relative to spending hit dice during rests. Players will have a much larger incentive to accumulate as many potions as possible, because their hit dice are much more important. This is somewhat balanced by requiring a hit die to purchase potions, although with higher-level civs it will be easy for them to purchase 4 or 8 at a time, or start mass-producing them. There are a few options for this:
1) Let it happen. Higher-level civs will give the party an extra hp reserve from the potion factory (which has a limited output), and that is part of the fun.
2) Limit healing potions to one per short rest.
3) Healing potions are made with addictive ingredients, and every one consumed after the first, per long rest, requires a Charisma saving throw (DC 10 + total potions consumed) to avoid addiction and adding a character flaw.
4) Roll on the Potion Miscibility chart (DMG pg. 140) for each potion after the first, per long rest.
Some game abilities, like the bard’s Song of Rest or the Chef feat, trigger on spending hit dice to heal. Under this system, the party cannot choose to take multiple short rests per session, so you should let these abilities work once per short rest even if no hit dice were spent to heal.