A shared campaign establishes a framework that allows a player to take a character from one DM's game to another one within the shared campaign. The roster of potential players can be quite large, virtually ensuring that any session has at least the minimum number of characters needed to play. And if everybody shows up to play at the same time, multiple DMs ensure that everyone can take part.
Shared campaigns often need a champion - someone who takes on the responsibility of organizing and maintaining the group. Kind of like a head DM. In our case, this champion is Topher.
Designing adventures for a shared campaign involves a different set of considerations than designing for a standard group of players. Most importantly, the adventure must be timed to conclude when the session is scheduled to end. You also need to balance combat encounters for a range of levels, since a wide range of characters might be experiencing the adventure at the same time.
Adventures in a shared campaign should typically last one session. Assume roughly 3-4 simple combat encounters or 1-2 complex ones, and three or four scenes involving exploration, investigation, and/or social interaction.
Combat encounters should be placed in one of the four tiers of play. Tier 1 includes levels 1-4, tier 2 is levels 5-10, tier 3 is levels 11-16, and tier 4 is levels 17-20. Within each tier, it's a good idea to use a specific level as a starting point. Assume a party of five 3rd level characters for tier 1, five 8th level characters for tier 2, five 13th level characters for tier 3, and five 18th level characters for tier 4.
Experience Points: We're going to be using Variant XP rules. It's just like regular XP, except you get it from just playing the game instead of from killing monsters or accomplishing story goals.
Treasure: Currently working on coming up with a good system for this.
There is a style of campaign known as "West Marches", named after a setting that one of the first campaigns of that style took place. A West Marches campaign takes place in an area largely dominated by unexplored wilderness. Players in a West Marches campaign choose when they want to play, who they want to group up with, and what they want to explore/do. There isn't a regular plot in a West Marches campaign, the story is about the players making a name for themselves.
West Marches style campaigns give players a lot more agency. The players tell the DM where they want to go and what they want to do there prior to the session, giving the DM enough time to prep. I really like this idea.
Shared Campaigns and West Marches take a lot from each other. It's possible to run a shared West Marches campaign with multiple DMs and everything. I want to take inspiration from West Marches when thinking about this campaign.