This came as I made my special rule for an S-FM, and clementine added more.
Role Name:Undercover Agent
Alignment:Town
Game Size(s):I have no idea, though I think it would work in smaller games better
Abilities:He has the investigative powers of a Sheriff/Investigator (don't know yet, or perhaps host can choose this), but the special thing is that he can use -reveal to announce himself to the town, gaining guaranteed trust, but losing his investigative powers.
Win Condition: See all Mafia and evildoers dead or something similar.
Intended Purpose:It can make an interesting role for town, and you have the dilemma of deciding when to reveal. If you reveal early, you will have little to no information, but you will be a trusted town ally from the start, if you reveal late... well, you will have a lot more information, but you might not even survive until reveal.
Meta-Game Implications: I have no idea what this means
Possible Cons:After early reveal, it can make difficult WIFOM situations for Doctor, to deicde who to heal, the confirmed town or perhaps someone else who might be attacked, and in dome cases the Agent can hog the Doctor for the entier game. Having a Spree-killer in the setup might make it better.
One Sentence Summary:An investigative role that can reveal during the day losing his other night actions, but becoming a trusted town.
P.S. clementine basically made this, I kinda only gave the idea with my setup