This is a odd version of a werewolf game. The rules are pretty simple and will go down like this:
Each player that joins the game will PM three custom roles to the GM. Teams, victory conditions, powers, artifacts, groups like masons etc. can all be made. When the game then starts the narrator will pick between all the roles that have been made and then randomize them between all the players.
What teams, powers, artifacts and victory conditions that will be in the game is mostly up to the players but some roles might be edited by the narrator to being playable.
Otherwise it's going to be like a classical Werewolf game with a nightphase where night actions are usually used and a day phase where people decided a lynch.