I did not invent this game; Dimitry Davidoff did, in 1986, under the name "Mafia". I didn't come up with the werewolf version, either. I am merely adding my own personal flair, along with my own graphics. Please enjoy this game.
Step 1: The Objective
The objective is best described for all players in one word: Survive !
The villagers desperately want to kill the werewolf so that they can live for another day. The werewolf, in turn, wants to kill all the villagers so that it can survive the game.
Step 2: The Characters: the Moderator
It's your job to : Keep track of who the Werewolf and the Seer are
Keep track of who is alive and who is dead.
notify the players when it's nighttime
ask the werewolves who they want to kill
ask the seer who they want to know about and give them a reply of "Werewolf" or "Villager"
Notify the players when it's daytime
Notify the players when it's time for a vote
Notify the players if they killed the werewolf or an innocent villager
Soundtrack : "The Creationist" by Kerli
Step 3: The Characters: the Villager
Description : Everyone in the village, food for the werewolf.
Basic Strategy : Individually, the weakest character in the game, but collectively you can kill the wolf and win the game! Deduce who the Werewolf is and convince the others to kill them.
Tips for Success : Someone's lying, someone's telling the truth, and the rest don't know any more than you do. Learn which is which, and the game is won.
Soundtrack : "Blame it on the Girls" by Mika
Step 4: The Characters: the Werewolf
Basic Strategy : As the werewolf, you have the most power in the game. Every night, you get to pick a Villager to kill and remove from the game. Naturally, the Villagers want to kill you and protect their own lives, the selfish bastards. Your only hope is to deflect their suspicions onto others in the game, tricking them into believing you are one of them.
Tips for Success : Locate and kill the Seer as soon as possible, they are your biggest threat as they can see through your lies with absolute clarity. You can cast suspicion on them by pretending to be the Seer yourself, casting accusations on someone else (this really only works once, as your "vision" will be immediately proven false, and will backfire if used wastefully, instantly making you the most suspicious)
Soundtrack : "In for the Kill" by La Roux
Step 5: The Characters: the Seer
Basic Strategy : As the seer, you get to peek behind the veils of people's lies to see the truth. This power makes you valuable to the Villagers, because you know the absolute truth. However, this makes you the most dangerous player for the werewolf, and so they will likely kill you the moment you make your position clear. it's best to keep your ability hidden as best as possible to avoid suspicion.
Tips for Success : Once in a while, go with the majority and vote with them, especially if the majority is voting for the werewolf, but even if you know the player is innocent. Going with the crowd dissolves suspicion. Outing yourself as the seer should only be done when you find the last werewolf, when you are sure you can lynch them before they can kill you.
Soundtrack : "Little Red" by Cathy Davey
Step 6: Setting Up the Game
for games of seven or less, one werewolf is ideal. for games of 8 or more, two werewolves are ideal. if the number of players exceeds 15, add a third wolf, and add a fourth wolf past 23. i researched the statistics, and these numbers create more balanced games.
Step 7: The Nighttime
say "it is now nighttime, everyone close your eyes and hum a lullaby to yourself until morning."
say "werewolf, open your eyes and choose a victim for tonight's feast"
look for whom the werewolf has chosen, hold your hand over the victim's head to confirm.
once you have confirmed the victim, say "alright, tonight's victim has been chosen. werewolf, close your eyes."
now say "Seer, open your eyes and point to the person whose soul you want to see"
as with the werewolf, look for whom the Seer has chosen to read, and hold your hand over their head to confirm. move away from the person so as to not draw undue attention and announce "werewolf" or "villager" according to what the individual's card is.
In the case of the first night, where the game begins, the mod goes through as stated above.
Step 8: The Daytime
During the day, the Villagers are able to profess their innocence, cast doubt on others' testimony, or accuse one another. Players can say anything, but the dead must stay silent. At the end of the day, there will be a vote on who the village thinks the Werewolf is, and the unlucky fellow will be lynched. If the person who is lynched is the Werewolf, the game will end and the rest of the Villagers will live. However, if the person lynched is innocent, the game continues, and the Werewolf will find a new victim that night.
Say "It is now daytime, everyone open your eyes"
Point to the person the Werewolf picked to eat the night before and say "You were eaten in the night" and remove the person from the circle.
say "Now it is time to deliberate and try to figure out who the Werewolf is. Talk amongst yourselves."
allow the players to talk. when people seem to have made their decisions, call for a vote. use your discretion.
say "now it is time to vote for whom the group thinks the werewolf is."
walk around the circle, stopping behind each person, and hold your hand over their head while saying "everyone who think this person is the werewolf, raise your hand."
count the votes, and keep track of who has the most
when the totals are collected, announce who the group has decided to kill by placing your hand over their head and say "this person has been declared the werewolf and will be lynched."
ask the player to reveal their card.
if it is a Villager card, say "The village has killed an innocent Villager. The Werewolf will come for a new victim tonight."
if it is a Seer card, say "The village has killed the Seer, the one person who knew the truth. The Werewolf will come for a new victim tonight."
if it is a Werewolf card, say "The village has killed a Werewolf, the town is now safe from it's horrible reign. sleep soundly knowing you are safe tonight. The end." if there is more than one Werewolf, the Villagers are, of course, not safe, and the game is obviously not over.
Step 9: Winning the Game
Villagers win: They lynch the werewolf and everyone left alive wins
Werewolves win: The Werewolves are not figured out before their numbers are equal to the villagers left, and they get to eat everyone.
Step 10: Alternate Rules
Cupid : One villager is also the Cupid. At the start of the game, he secretly indicates two other players. These players are now a pair of Lovers. (The moderator taps the Lovers on the shoulder, and has them open their eyes and see each other. So the Lovers know who each other are, and the Cupid knows who they are -- but none of them know (initially) whether the Lovers are human, wolves, or one of each.) Now: if one Lover dies (day or night), the other dies immediately of a broken heart. Furthermore: if the Lovers are the only two people left alive, even if one is a human and one is a wolf, they both win.
Join the Pack : In this, the villagers don't lynch -- they choose someone to test, and the subject is only killed if he is a genuine wolf. And after a successful detection, the villagers get another go; the day only ends after a test comes up innocent. (The first one's free, so there at least two tests per day.) What's the catch? At night, the werewolves pick a villager to convert. Their victim starts playing for the wolf team immediately, although he won't find out who infected him until "werewolves, open your eyes" the next night. I am told that the play dynamics are wildly different, since you're looking for changes in behavior, not hidden conspiracies.