In general, I have no problem with mercenary being a convertible class but I would like to see this one little change to him. Passive: On The Job - You cannot be converted while Guarding your target.
I go to guard my target on Night 1, get converted, only to find out they didn’t get the notification that I had stood outside their door. I did not have fun that game.
It’s also really awkward mid-game for this to happen as you have no way to prove you still the merc without using the Guard ability.