My cousin recommended a fantasy book, Eon. I haven't finished it yet (almost to the end) but it's very interesting and the concept of it all. Of course, I always prefer dragons to not be the back benchers and to the in the frontlines but in this story. Dragons were merely power spirits that gives the owner magical powers. They are not physically visible however only the Dragoneye (the owner) can see but only in rare occasions. There was one where the author described the Rat Dragon. It having pale blue scales but turning to ocean blue on its undersides and broad chest with thick white beard and a pearl tucked under it's chin (it's source of power). Those are the main features I remembered and I came up with this :) Rat Dragon's characteristic is it's compass is north-northwest, it's colour is blue and the Dragoneye is Lord Ido and this dragon is the keeper of ambition