Compulsive is a role modifier such that the role must use its Night Action each Night unless some external factor prevents the player from doing so. A player with a Compulsive action cannot submit "No Action", and if they fail to submit an action, the player is either modkilled or the action/the action's target is randomized.
The most common role with this modifier is Vigilante.
This modifier is considered Normal on mafiascum.net if the following rules are met: the role PM for a compulsive role must specify that the player with the role, when they confirm, must include an ordered list of all players in the game. If they ever fail to submit an action, their action must be resolved as targeting the first player on that list that is still alive. They are allowed to change the order of the list at any time, e.g. if they think they might accidentally fail to submit a night action. This is done to ensure that compulsive roles can have an action chosen non-randomly for them in the event that they fail to submit.
Use and Power
The Compulsive modifier is generally used to ensure that actions are used when possible. This is usually ascribed to roles that are pivotal to the setup. By making Vigilante Compulsive, the rate of death can be controlled throughout the game, thus allowing the game to be easier to balance. An example of a role that is Compulsive due to its importance to the setup flavor-wise is Dreaming God.
A role's power is usually only changed slightly by making it Compulsive.