Spy

Mechanics

 * You will be able to read all whispers, even if you are dead.
 * When listening to the Mafia talk at night, their names will appear as "Mafia".
 * When roleblocked, jailed, or dead, you will still listen to the Mafia talk, but not see who they visit.
 * The Spy keeps most of his abilities while dead, making him very useful to Town if it has a Medium.

Strategy
Player 1:''Hey! Remember me?'' Player 2:Yes.
 * If the Mafia members call each other by name in their chat, do not rely on these being their actual names, as Mafia often expect a spy to listen.
 * When the Mafia has a Blackmailer you should try to figure out why the Mafia is trying to keep the blackmailed person quiet. Maybe they blamed the Mafia, and you don't have to reveal yourself as spy to point out that someone is blackmailed since you can just say that the person is being quiet and ask them to for example to vote for you if they are blackmailed. Then tell everyone what they said before they were blackmailed.
 * However, keep in mind that if the Mafia predicts that high-priority roles will be too well protected, you could get slaughtered.
 * Pay attention to all whispers, as you will know who sent them, who received them, and what the message is. The smallest details may provide clues to who is mafia. Example:
 * Day ends* Mafia: Kill that guy, I know him.
 * Spies are one of the few roles that retains some of their abilities after death; while you no longer see Mafia visits, you still see what they discuss and can still see whispers. Provided there's a living Medium, you can help the Town in many ways.  If nothing else, even reporting the exact contents of unimportant-seeming whispers or a manufactured Spy test to the Medium can give them a way to prove themselves.
 * Since it can reveal easily, it often makes sense for the Spy to claim Survivor in order to decrease the chance that they'll be targeted by the Mafia; if the town tries to hang you, you can easily prove yourself.  However, claiming Survivor does increase the risk that you'll be killed by a Vigilante (whose attacks won't leave you a chance to prove yourself) or a Jailor (who might refuse to believe you if you go from claiming Survivor to claiming Spy in jail.)
 * Look out for incorrectly spelled words, such as a Mafia member using the wrong there, their or they're, and using the same incorrect usage over and over again. This can lead to you finding a Mafia member, but a downside is that the Mafia can pretend to be people by using the same spellings as them.
 * If someone else claims Spy and their claim does not fit in the role list or they weren't visited by the mafia at all, there's a high chance that they could be a Blackmailer. Write it in your will or call them out on being a Blackmailer when you can before the town trusts him and ends up revealing info to the Mafia.
 * Some information from the Mafia can be trusted more than others.
 * If the Mafia names someone as immune, it's often accurate -- the Mafia needs to share information about that in case their killer changes (or, in the case of a Godfather directing the Mafioso, so the Godfather knows not to target that person again), and has no reason to keep information that would lead to rival killers from the Town. If you're not sure, go back over the last day to see if anyone was killed and who the Mafia visited.  Sometimes the Mafia will use this to try and give themselves cover if the killer was roleblocked or jailed, but this is rare.
 * If the Mafia names a living person's role, it's usually a sign that they have a Consigliere. If they name the role or describe the will of a dead person who was cleaned, it's often the Janitor speaking.  Again, these can often be trusted because this is information the Mafia sometimes has to prioritize sharing among themselves even at the risk of leaking it to you; and again, information that leads to a rival killer should be taken seriously, since the Mafia has plenty of reason to want to expose them as quickly as possible.
 * That said, never trust anything the Mafia says 100%; consider whether it makes sense in the light of the rest of the information available to you (for instance, if they say someone is a Serial Killer or Arsonist, have there been Serial Killer attacks or people claiming they were doused?)
 * An interesting high risk/high reward strategy is to claim Survivor day one as Spy. This will likely keep mafia off your back for a few days, and even if you see them visit you, you can always confirm you are actually spy and write who the mafia has visited. If the actual survivor or amnesiac calls you out in Ranked Practice or Ranked, consistently claim you are survivor until you are put on trial, where you can easily reveal you are spy and ask for protection. Usually, the "survivor trick" keeps the mafia or evil roles thinking you are survivor for multiple days. The problem with this tactic is that the mafia or neutral killing roles may want to check if you are survivor, and attack you. Also, a vigilante or jailor may want to take a shot at you and not only end your life but also waste their executions/make them die of guilt.

Revealing

 * A "spytest" involves asking people to whisper each other and telling them what they said. Only Spies and Blackmailers can do this, so this easily proves your innocence in most cases and is a useful way to keep yourself alive if you're put on trial. However, if people have been blackmailed during the game, this won't suffice as proof.
 * A variation of this strategy can be used if you are dead. If a medium is being suspected of being a Janitor, the Medium can initiate a spytest and repeat the message the following day. If the whisper happens to go to a mafia member, there will likely be a short exchange at night about it, too. This not only confirms a medium, but it has a chance of mafia detection as well.
 * If you are unable to gather a lot of information but still have some information to contribute, a good time to reveal yourself as a Spy is when you know there are a lot of targets as lots of other roles at this point are a higher priority to kill than the Spy. Otherwise, you should reveal yourself when you have some good information to contribute with, for example, if you know who one of the Mafia is.
 * It is possible, but risky, for a Spy to initiate the same strategy of a Mayor game -- revealing yourself through a spy-test at any point, demanding roles from everyone, and using that to guide the town's voting. The problem is that without a Mayor's decisive three votes, the rest of the Town is less likely to listen to you.  However, you do have the advantage that a Doctor can heal you even after you've confirmed yourself.

Mafia Visits

 * Make sure to keep track of who the Mafia visits at night, in most cases the visited target will not be a member of the Mafia. You can use this information to narrow down who could be Mafia. However, a Witch or a Transporter can make a Mafia member visit another (if this happens, Mafia members will often point out that they were visited by the Mafia). If an Amnesiac becomes a Mafia member, they might be among the targets too.
 * If no targets are visited at all, it is very likely that the Godfather or Mafioso was in jail or roleblocked. In modes where the number of Mafia can vary significantly, such as All Any, it can also indicate that the Mafia are all dead.
 * If a target is visited repeatedly but is not blackmailed, the Mafia might have a Consort or Framer.
 * If you see that multiple Mafia members visited a single target during the night, but a different player was killed by the Mafia the next day, the target is most likely now a Disguiser who stole the identity of the target, especially if three or more mafia visit a person and someone else ends up dead and cleaned the next day.
 * If none of the targets die, it is possible that one of the targets was attacked and either immune or healed by a Doctor. This is especially true if a target was visited by multiple Mafia members (the second being a Disguiser, Forger or a Janitor).

Mafia Counter-Strategies

 * "Accidentally" give out a fake name in mafia chat, saying something such as "Hi -player-, we were in last game together" or "-player-, kill him". This tactic is the least likely to work as the Spy might know you are trying to trick them, and visiting one of the targets you frame in chat gives away that you are simply spouting false information.
 * Mislead the Spy in what roles he thinks Mafia has. For instance, if the Mafia lacks a Consigliere, say something like this in chat: "Invest this target." Respond to yourself with an "okay" or something similar to make it seem like two people are talking. The next day, respond to yourself giving a role to the "investigated" target. The Spy will now suspect actual Investigators of being Consigliere.
 * Keep in mind that someone has to visit the target you are investigating, so that Spy knows the target was visited. This works best with Framer, Disguiser, or Janitor, who should have no obvious effect upon visiting (unless the target dies, in which Disguiser/Janitor are potentially revealed).
 * Pretend to be another person by using the same incorrect spellings of words they often say, such as a Townie using the wrong there, their or they're, and you, a Mafia, use the same incorrect spelling in the same context as the Townie. For example, Townie says "I think that their Mafia," using the same spelling, at night, you say "Their going to die tonight." A downside to this is that not many spies pay attention to spelling, so it might all be for nothing.
 * If you are uncertain if you should do your night ability, ask the mafia "Should I do it?" or some other non-specific phrase. That way, you can do your night ability in the right situation and make the Spy be uncertain of the mafia's roles.