Definitely my favorite expansion. This one calls for all out attacks on your opponents. The dragon rampages about the land, eating up meeples and allowing you to take out your opponent from that valuable field he's holding onto. This princess (which only appears in cities) allows you to remove your opponent's knight from a city. The fairy offers some protection from the dragon and gives you a few points here and there, but your opponent can easily take it away at critical moments. A great expansion adding in lots of new elements that can make or break your game.
A good expansion that adds an element of semi-controlled chaos with the dragon rampaging around the board, knocking meeples off their tiles. The Princess adds a way to get more points (but the best part is the dragon).