The only rule every cultist must follow is that she should worship and show great respect to the great Cthulhu at all times. If a cultist openly shows disrespect of Cthulhu she will be banned from the cult. One way of showing her respect, is at the Ceremonies which are held every now and then in the guild halls. A cultist can be rewarded handsomely if she pleases Cthulhu, and punished if she fails to do so.