In a dungeon, it can be tough to keep track of different factions, assuming your players plan to do more than just kick in the door, slaughter everything that moves, and loot the corpses.
I know for my Megadungeon project, I've already got lots of different groups, but limited space in my notebook to jot everything down. So I wrote up these little reference sheets to keep things a little easier to manage. Each faction gets space to write down who they are, where they are, who their leaders are (up to 3), what the faction wants, what they need, their rivals, then some extra space for any other notes you need to write about them.
Letter Size or