I decided to work on a new campaign in the setting I've been using and tinkering for the last five years. Having fallen in love with Worlds Without Number, I now want to really give it a try running it as a West Marches campaign, which has a large group of players who get together in smaller parties to set out from a main town on smaller exploration adventures and then return with their treasures to share their discoveries. Such a game can easily grow to a size where having more than one GM becomes really useful, and I also want to put the focus on discovering a strange and wondrous setting, and the players cooperating on getting a better understanding of the environment and creatures that they are exploring. This means that a lot more details about the world need to be well established in the past, so that all GMs can reveal pieces of information that the players can actually put together into a bigger picture. Previously, my worldbuilding had been very focused on the large scale, establishing the general environmental, cultural, and magical conditions, and only creating specific stuff for whatever place the characters in my campaigns were currently passing through. For this campaign, the worldbuilding needs to be more about detailing specific villages, prominent local ruins, small factions like single gangs or clans, and various specific NPCs. Mostly I will be just dumping here whatever I just made, as putting it down into actual sentences always helps me a lot with deciding on smaller details. But any ideas about how I could expend the things I post with additional details, or new places I could put down in this world will be hugely welcome. I'm probably going to need large numbers of relatively small size, with just 5 to 10 rooms and three encounters or so each, so even if an idea doesn't quite work with what I have in mind, it could still be a great starting point for an additional size.

The Setting Concept

The setting for the Great River Campaign is the Mahnad River on the continent Kaendor, which is part of a planet covered almost entirely in forests and oceans and dominate by vast wilderness with only a few small places that have any kind of civilization. The setting takes great influences from Dark Sun and Xen'drik and is heavily inspires by Morrowind and Kenshi. So inspect lots of strange and big reptile and insect creatures, alien plant life, bronze armor, jungle ruins, and bargemen going down the river past rice fields in round straw hats. It's all supposed to be a little bit bonkers, but always with a sense of sincerity and wonder. It's meant to be fun, but not funny.

The Mahnad is one of several large rivers that run into the Inner Sea, whose coasts are the center of civilization in Kaendor. But even as a major waterway, the only the lowest 200 miles of the Mahnad are settled to any meaningful extent. Another 100 miles further upstream, one reaches the limits of where the river traders go in their ships, and what for most people is effectively the end of the known world. But the Great River extends much further than that. Only a small fraction of the giant river has ever been mapped, with the rest being a true wilderness where few people have ever tread.

Technologically, the current civilizations of Kaendor are at a quite advanced Bronze Age level, and culturally draw from India and Persia, but also Egypt and Greece. Except that this world is almost completely heavily forested and the populations are too small to form any great kingdoms or empires. Instead, their technology relies heavily on what the people found left behind in the ruins of previous inhuman civilizations that existed around the Inner Sea and beyond across many thousands of years. The last civilization was the Naga, who are still around and control much of the jungles further south, but abandoned their cities on the Inner Sea and the Mahnad several centuries ago when the climate in these more temperate regions became too cold for them. As people emerged from the deeper forest and mountains to explore the abandoned cities, they found enough to work out the basics of working bronze and growing rice, and eventually learned to decipher the ancient tablets and scrolls that held magic much more advanced than that of the early shamans. Most cities and large towns are still build in and around the ancient walls of earlier civilizations. But many more ruins still stand overgrown and undisturbed deeper in the forest, and while the magic of sorcerers and high priests can rival that of the ancients, the creation of new magical artifacts is still as slow and expensive as it always was, making the recovery of items hidden away in ancient vaults and tombs an extremely lucrative undertaking.

The Great River is based on the Mississippi and Yellow River, and while it's actually a good deal smaller than either of those, it's still a massive area. I assume that it would take many years for any PCs to reach the source of just one of the main branches, but should the campaign get to that point, I like to be prepared to have clues for what the players might encounter if they get there long before that. The main bulk of the material I am working on now is just for the Lower River, which makes up about a fifth of the entire total area that could be explored by characters traveling on the river.

The Campaign Concept

While this thread is really about the worldbuilding of the setting, I think the general idea of how the campaign is supposed to work out in practice might help a lot with putting many of the choices and decisions into context.

The game system I am going with is Worlds Without Number, which is primarily based on the 1981 Basic and Expert rules of Dungeons & Dragons, but has been extensively modified and expanded in ways that I've seen many people any myself give the impression of being greatly inspired by 3rd edition. It has both skill points and feats, which work similar but slightly different, and the familiar combat system of Standard Actions, Move Actions, Instant Actions, and Reactions. But it also has much simpler character customization, much fewer modifier to rolls, much smaller attribute modifiers, only three classes, and a much overhauled magic system, which all make still feel very much like an oldschool retro-clone. This is significant in that it makes not just combat much faster, but also allows for creating a character in under five minutes. It's also a system that makes it possible to learn the game as you go without knowing any of the rules in advance.

As a West Marches campaign, the overall premise is that there is no fixed party of player characters. Instead there is a larger number of players who don't all play at the same time, and will form parties for just a single adventure as it fits everyone's time. With the way I am planning the campaign, adventures for more higher level parties to more distant places will get increasingly longer and not get completed in just one day. But for lower level characters, who explore closer to the starting towns, adventures are intended to be completed from start to finish in three or four hours. If there's still unfinished business and unclaimed treasures at a site, some of the characters can go on another adventure to that place, likely with a party of different companions. The idea is that any player can simply join an adventure that has still room fore players, make a character in five minutes, and play for a single game just to see how it is. If it remains at that, there's no issues for the other players or the campaign, as the adventure should have been completed and the party disbanded anyway. It's easy to join a game spontaneously without need for lengthy preparation, and players don't have to commit to any future adventures at a fixed schedule. This is where the ability to easily make new characters on the spot becomes very useful. A party going on an adventure that spans three or four days can consists of both players who play only once or twice a week, and players who like to play twice a week. The players playing more often don't have to wait on the players playing less frequently, since they can play with another character in other adventures in the meantime.

This approach of having multiple characters in different adventures requires a certain approach to the relationship players have with the characters and the campaign as a whole. This is a campaign style in which each PC has to be treated as somewhat interchangeable. This is not a type of game that lends itself to great personal character stories or character relationships. Having a system with limited character customization helps with that, as less time and effort goes into constructing these characters. An expectation of a significant level of lethality and real chance of character death should also contribute to that end, though the actual degree of danger does not have to be that particularly high. It just needs to be clear to the players that the chance is very much not zero.
A certain detachment from the PCs means that engagement and investment in the game has to come from somewhere else. I'm not good with exciting puzzles or challenging tactical combat as the main thing to carry a campaign, so my approach is to put the focus on exploration. My goal is to make the players excited about discovering the world they are moving into, and to provide rewards for studying the civilizations that build the ruins and the creatures that inhabit it by enabling them to get around certain types of common challenges more easily. My hope and gamble is that the characters making these discoveries can fade more into the background, and the discoveries themselves become the center of the campaign. This idea is very much inspired by the way worldbuilding is used in The Elder Scrolls and Dark Souls. But to make that work and be genuinely interesting to players, the worldbuilding has to be really solid and imaginative.

In regard to mechanical incentives, I have decided to stick with the oldschool D&D approach and tie experience primarily to treasure. The party gets 1 XP for every silver piece of treasure that they bring back from an adventure, and the amount of treasure that can be found in any place is between three or four times the XP that would be gained from engaging all the potentially dangerous creatures in that site. These treasures are primarily in vaults and caches, not carried around by creatures. This means that getting the treasure without having to face the guardians, and keeping the amount of random encounters as low as possible, becomes the safest way to gain good amounts of XP with the lowest risk of being killed in the process. While the focus of the campaign is not on getting rich, spreading the treasure out evenly through sites can make it somewhat of a measure of how well the site was explored by the players.
An additional resource in Worlds Without Number is renown. Renown primarily allows characters to get favors of assistance from rulers and populations. These favors could for example take the form of helping construct new outposts deeper in the wilderness, and convince traders to make the extra trip when they are doing their regular rounds to keep those outposts supplied, which shortens the travel time to more distant ruins. Characters automatically get a point of renown each time they are played, but as an additional source players can write play reports of the things they discovered in each game. These reports represent tales that the characters share with other explorers in taverns along the river, gaining both acclaim for themselves, and contributing to the shared knowledge of what lies deeper in the wilderness. These reports can include information that can be very useful to other players on their adventures, expanding the campaign as a whole beyond the active play time, and connecting players to characters of players that haven't played with much. Having read the tales of other characters' adventures might contribute to other players wanting to go on adventures with these people they already heard so much about.