I really doubt there are 3 mafia and since That guy was added after the initial roles were given he wouldn't be one of the mafia. The only evidence of Onyxmeth being a mafia is the way he's trying to turn everyone on That Guy. I believe there is a greater chance of Onyx being mafia but if he isn't he could be a doctor or cop, if that guy isn't mafia than he would have to be a townsfolk. I'm leaning towards Onyx right now.
VOTE ONYXMETH