From SA Mafia Wiki
A Doctor (or Doc) is a common protective role. In general, Doctors are town-aligned, though Mafia-aligned Doctors are occasionally present in games with multiple scum groups or many non-mafia killing roles. During each night, a Doctor may protect one player from being killed. In general, Doctors are not allowed to protect themselves, but may protect any other player as often as they wish. If you have a Doctor role and it is unclear what the limitations (if any) of your action are, ask the moderator of the game.
There are a few roles that put a spin on the traditional Doctor role.
- Weak Doctor: Similar to a normal Doctor in that they protect their target, but they die if they protect a Mafia-aligned player (or, in some cases, any non-town target).
- Firefighter: Firefighters are used to prevent specific types of kill that are linked to one particular scum group or player. The most common use for the role is in tandem with a Serial Killer - while the Firefighter can protect players against the SK, they cannot protect players against the Mafia.
- CPR Doctor: A CPR Doctor is a combination of Doctor and Vigilante. They can save players who are targeted for a kill, but will kill players who are not targeted for a kill.
- White Mage: A doctor that protects their target both the night of the protection AND the subsequent night.