In a world, where town mustn't randomly lynch or risk killing civilians, the most critical role for them. If 3/4 civilians die it's the end of the line for town. Arsonists will not know who the terrorists are. Will mafia take each other out? Can the terrorists strategize how to pick town off without losing the battle early? Will mafia be the ones getting bombed after all? Stay tuned! In a set up where stranger things have happened. (as has been tested over and over again)
Detective... you should probably out, to save your civilians.