And now the thread is dead. -_-
Based on Ax's post, we now know that 1. there (probably) isn't a Firefighter, and 2. we have some other role that can "stop" the Arsonist in some way. Whether that means the role prevents the Arsonist's night kill in some way, or whether it "cures" the Arsonist like the Psychologist/Psycho, I have no idea.
Anybody got any theories? Anybody want to say anything?