I think some sort of big burning demon would be great and in Fable 2 when we ar evil we could leave burning footprins!
or even have torn wings and we could fly so we could engage those aiborne mobs and when we are playing as a good one then we would have beautiful feathered bird-like wings like the anngels have this will be not too fableish though. And there could be mobs like the elementals but they would not be elementals just like them, like pure fire or lighing and they would not be called elementals and they would have an antropomorf body but instead their legs they would have there pure lihgtning or fiire and they would surprisingly emerge from fire and they would have their own wrold in another realm but that is not too fableish. And as for the giants adn the like that is a good idea but I think orcs are out. oh and I even drew that antropomorf pure fire thing mob but I don't have any digital camera or scanner. But If I get hold of one I post my little crature