Create a subrule to “Doomsday Cult”, called “Cult Attacks”:

As a weekly action, a Cultist can send a private message to the Leader stating that they’re organising an assassination of a Cultist. Upon receiving this message, the Leader should reduce the Stamina of the chosen Cultist by 5, with the reason “Cult activity”.

Create a subrule to “Doomsday Cult”, called “Revenge agains the Cult”:

As a weekly action, a non-Infected Survivor who has previously had their Stamina due to Cult activity can perform a Fitness Check to try to fight back against the Cult. If the check is passed, then the next time the Leader reduces the Stamina of anyone due to Cult activity, he should reduce the Stamina of a random chosen Cultist by 5, with the reason “Cult activity”; the order in which the Staminas are reduced should be chosen at random so as to not give away which target was the Cultist, and which was the Cult’s target.

Create a subrule to “Doomsday Cult”, called “Locating the Cult”:

As a weekly action, a non-Cultist Survivor can send a private message to the Leader, specifying a Survivor who he wants to Investigate; that Survivor becomes an Investigated Survivor for that week. As soon as is reasonable after the start of each week, the Leader must make a post with “[Investigation Results]” in its title, listing all Investigated Survivors for the previous week, along with either “Cultist” or “Non-Cult” for each; one of those notations (chosen at random by the Leader) must be correct, and for each of the others the Leader must make it correct with a 60% chance, and incorrect with a 40% chance.