Inside Blackrock Mountain, two ancient powers have been feuding for ages: the elemental fire lord Ragnaros, massing his forces in the Molten Core, and the black dragon Nefarian, running his operation from the mountain's upper reaches. The player is drawn into this conflict, taking on five wings of bosses and class challenges to add their exclusive cards to a collection—then facing Heroic Mode to prove who truly rules the mountain. Nefarian's encouragement feels genuine. It probably isn't.