You have a group of people. About 15 is probably the minimum to make a really good game. The Gamemaster randomly chooses the roles of each person:

1 doctor

1 detective

3 mafia

10+ citizens

The point of the game is to NOT DIE. Or in the cases of mafia, to make sure at least one person in your group survives and is the winner.



Each character has a role, and each character has different roles during the Daytime and Nighttime Phases.

The Daytime and Nighttime Phases are just phases in the game where different things will happen and certain roles will be carried out. They won't actually happen during the day or night; the Gamemaster will announce the start of
each Phase.

 Each person has one vote per Daytime Phase that the Gamemaster will record. All votes will be publicly posted. They can change their vote anytime they like before the Nighttime Phase. At the end of the Daytime Phase, whoever
has the most votes cast against them will be "Lynched" or killed. Their role will be revealed and they will be ejected from the game.

The Nighttime Phase
is when discussion ceases, and each member messages the Gamemaster to fulfill their respective duties. These will be
explained in the character role explanations.

MAFIA:

Mafia are out to kill, and try to convince everyone they AREN'T mafia. They'll be discussing and acting like they're citizens just like everybody else; trying to "discover who the Mafia is". In other words, for the people who ARE in the Mafia, they are trying to divert the attention AWAY from the mafia members and pin the blame on innocents citizens.

All Mafia members will know who the other Mafia are, though they will not know the roles of the other members.

During the Daytime Phase, Mafia will discuss and chat like I mentioned above. However, they will also discuss in a private chat amongst the other Mafia who to kill during the Nighttime Phase. Their biggest concern is to weed out the Doctor and Detective, or anyone getting too close to discovering the identity of a Mafia member.

During the Nighttime Phase, the Mafia will contact the Gamemaster through a private chat about who they collectively decided to kill. Their victim will be announced at the beginning of the next Daytime Phase.

DOCTOR:

The Doctor is an important role. During the Daytime Phase, the Doctor will discuss and poke and prod and investigate like everyone else. However, they are also trying to convince everyone that they are simply citizens. Though the Doctor is a “good”
role, the Mafia would kill them if they knew their identity. However, their role is also to keep a close eye on the goings-on and make an educated guess as to who they think the Mafia are going to kill during the Nighttime Phase.

During the Nighttime Phase, the Doctor will message the Gamemaster through a private chat and pick a member to SAVE.  This will be a member that they think the Mafia may choose to kill during the Nighttime Phase. If they pick the member that the Mafia were after, the member is saved! If they pick someone who was not being targeted, nothing happens.

DETECTIVE:

The Detective is also an important role. During the Daytime Phase they have the same role as everyone else. Their attention to who may be Mafia is especially important. They too should not reveal their identity since they have much power and the Mafia would snuff them out.

During the Nighttime Phase, the Detective will message the Gamemaster through a private chat and pick one member of the game. The member’s role, will be revealed to the Detective, regardless of what it is. It will not be revealed to the rest of the game; it is the Detective’s role to protect those who they know are innocent, and try to steer the rest of the members
towards lynching out someone who they know is Mafia.

CITIZEN:

The role of the Citizen is the same as everyone else’s during the Daytime Phase. They are trying to convince others that they are innocent, and trying to promote discussion to find out who the Mafia members are.  They have no role during the Nighttime Phase but to wait and hope they don’t get chosen to die.

This game goes on until either all Mafia are dead, or all Innocents (Citizes, Doctor and Detective) are dead. Last group standing wins.

I may set up Res prizes for this game too, in which case
this is how it would work:

Mafia member wins: All Mafia get a prize

Citizen wins: Just that Citizen gets a prize

Doctor wins: Just the Doctor gets a prize

Detective wins: Just the Detective gets a prize

This is due to the fact that it is much harder for Mafia to
win, as their intentions and patterns become clear as the game progresses and
more people are killed.

All in all, the point of the game is to survive using
deception, observation, and strategy. It’s pretty damn cool and games usually
go on for a few days.