Wondering this as well, cannot seem to find any local file that, when removed, affects my rank in a way that would result in it resetting back to 1 upon new files being generated. Makes me think there isn't actually any local file that stores information about your rank, and that it's handled server-side, which would be immensely disappointing. Tried removing my entire "players" folder from Plutonium, and all files from the "demonware" folder in storage, where I read the save data is supposedly held, yet in both cases, I still somehow loaded in at the exact same level I was before. Something isn't right there. If there is a local file that holds data about your multiplayer stats, then nobody seems to know where on God's green Earth it is located.