Well we now know fnaf 3 trailer is out so in the trailer there's some words while watching it like
He will come back, He always does, We have a place for him BUT WAIT HOLD IT!
These sentence are talking about SOMEONE we seen in the fnaf 1&2
so the new ROBOT could be someone in fnaf 1&2 like PUPPET,PHONE GUY,PURPLE MAN AND THE ROBOTS
am not sure if this is true but it sounds TRUE BUT I think it's the PURPLE MAN