Unlyncher

From SA Mafia Wiki

An Unlyncher is a role with win condition to prevent a specific player's lynch. If his target is lynched, he loses. Usually if the target dies by a different method the Unlyncher won't lose and either be removed from the game, or continue as a Townie or even Survivor. Depending on the mod, they may or may not be told their target's alignment.

They are the "opposite" of Lynchers.