Please welcome the most OP dragon in the entire K&C expansion: Duskbreaker. It costs only four mana and clears everything that your opponents might play before turn four -- that is how powerful this minion is.
Too bad it's specifically designed for Priest class only. Otherwise, it would've been an auto-include in each and every deck that runs dragons. In any case, Dragon Priest archetype will become a huge threat for all aggressive decks that rely on early, cheap minions from now on.