I came across an interesting idea that actually sounds rather fun.
https://bdubsanddragons.blogspot.com/20 ... -play.html
What are Patrons?
Chanticleer is an e-friend, tw1tter celebrity, and the DM of a 5e Waterdeep campaign that employed BROSR best practices; including JTK and downtime. He coined the term "Patron" for "characters who would be NPCs whose downtime is controlled by a Player".
I suggest reading the entire post if that sounds intriguing. I don't think I've seen this idea or anything like it suggested before despite it being so seemingly simple.With Limited Approach be aware that Patrons will be MUCH MORE ACTIVE, on the whole, than an NPC. There is no amount of random action rolls you can make for an NPC that is going to compete with a player controlling an NPC with major resources at his disposal.
A Patron Villain could be very dangerous to the PCs, for instance; using everything at his disposal to simply kill as many PCs as he can while they're resting at the inn. Patron Villains will do the sort of "unfair" things a DM would be too scared to do to PCs for fear of losing player loyalty to the campaign. Be wary of this effect when introducing Patrons, most especially villains. Having the villain be remote to the PCs "home base" will help mitigate a sudden assassination of a PC for instance. Or at least give the PCs time to become aware that Dairin the evil swamp Mage might send an assassin to kill them during downtime.
There's definitely the basis for some sort of two-tier game to be made here. A strategy play-by-mail(so to speak) sort of game and a micro-level RPG that's happening during.